PE5 ST 11-14
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Questions and Answers

Which simple machine has a fulcrum, effort, and load as its main parts?

  • Screw
  • Wedge
  • Lever (correct)
  • Inclined plane

What is the fixed point around which a lever turns called?

  • Axis
  • Load
  • Effort
  • Fulcrum (correct)

Which of the following is an example of a first class lever?

  • Crowbar (correct)
  • Bottle opener
  • Nutcracker
  • Wheelbarrow

In a first class lever, where is the fulcrum located?

<p>Between the load and the effort (A)</p> Signup and view all the answers

Which simple machine is characterized by the load being between the effort and the fulcrum?

<p>Second class lever (A)</p> Signup and view all the answers

Which of the following is an example of a second class lever?

<p>Wheelbarrow (D)</p> Signup and view all the answers

How many classes of levers are described in the text?

<p>Three (D)</p> Signup and view all the answers

Which of the following is a component of all levers?

<p>Fulcrum (B)</p> Signup and view all the answers

What is the primary function of a simple machine?

<p>To simplify work (D)</p> Signup and view all the answers

Which of the following is an example of a simple machine?

<p>Wheelbarrow (D)</p> Signup and view all the answers

What is a complex machine made of?

<p>Two or more simple machines (A)</p> Signup and view all the answers

Which of the listed items is considered a complex machine?

<p>Bicycle (C)</p> Signup and view all the answers

Which tool is specifically mentioned for simplifying the task of removing a bottle cap?

<p>Bottle opener (A)</p> Signup and view all the answers

Which of the following cannot be classified as a simple machine?

<p>Sewing machine (C)</p> Signup and view all the answers

What is the definition of a machine?

<p>Any device which is used to simplify work (C)</p> Signup and view all the answers

In a lever, what is the fixed point around which the lever rotates called?

<p>The fulcrum (C)</p> Signup and view all the answers

Which of the following tools is an example of a wedge?

<p>A chisel (A)</p> Signup and view all the answers

A wheelbarrow belongs to which class of simple machines?

<p>Second class (D)</p> Signup and view all the answers

A bottle opener is what class of lever?

<p>Second class lever (A)</p> Signup and view all the answers

What is the primary purpose of an inclined plane?

<p>To raise or lower objects (B)</p> Signup and view all the answers

Which of the following is an example of an inclined plane?

<p>A ladder (C)</p> Signup and view all the answers

Where might inclined planes be used to simplify work?

<p>Loading cargo onto a truck (B)</p> Signup and view all the answers

What is a wedge primarily used for?

<p>Cutting or splitting materials (A)</p> Signup and view all the answers

Which of these is an example of a wedge?

<p>A pair of scissors (D)</p> Signup and view all the answers

What is a common material used to make wedges?

<p>Wood (A)</p> Signup and view all the answers

What shape characterizes a wedge?

<p>Tapered (D)</p> Signup and view all the answers

Which simple machine is often used for splitting firewood?

<p>A wedge (B)</p> Signup and view all the answers

What is a sloping road an example of?

<p>An inclined plane (C)</p> Signup and view all the answers

Which of the following tools uses a wedge to function?

<p>An axe (A)</p> Signup and view all the answers

Which of the following is a primary use of levers?

<p>To simplify work (C)</p> Signup and view all the answers

Which tool is an example of a lever used for carrying loads?

<p>Wheelbarrow (A)</p> Signup and view all the answers

What type of lever is typically used to remove nails from wood?

<p>Claw hammer (A)</p> Signup and view all the answers

Which of these tools is a type of lever used for cutting?

<p>Scissors (A)</p> Signup and view all the answers

What is the general purpose of using levers?

<p>To simplify work (D)</p> Signup and view all the answers

Which of the following activities involves the use of a lever?

<p>Hammering a nail with a claw hammer (C)</p> Signup and view all the answers

What kind of tool uses leverage to cut hair?

<p>Scissors (B)</p> Signup and view all the answers

What is the main function of using a claw hammer as a lever?

<p>To pull out nails (A)</p> Signup and view all the answers

In what context might someone use a wheelbarrow as a lever?

<p>Carrying a load (B)</p> Signup and view all the answers

Which tool mentioned is specifically designed to make cutting easier by using leverage?

<p>Scissors (B)</p> Signup and view all the answers

How does using a wedge to split a log change the nature of the force required, compared to breaking it by hand?

<p>It requires less force applied over a greater distance. (B)</p> Signup and view all the answers

Considering the activity described, what is the primary advantage of using a mallet or hammer with a wedge?

<p>It increases the force applied to the wedge, making it more effective. (B)</p> Signup and view all the answers

If a wedge becomes stuck while splitting a log, what does the provided text suggest as a solution?

<p>Use a wooden wedge to loosen the stuck wedge. (C)</p> Signup and view all the answers

In what way does the shape of a wedge contribute to its function of splitting or separating materials?

<p>The shape concentrates force at a single point. (A)</p> Signup and view all the answers

How does the activity of using a wedge to split a log demonstrate the concept of work in physics?

<p>It illustrates the conversion of applied force into the work of separating the log. (C)</p> Signup and view all the answers

Which of the following best describes the relationship between simple and complex machines?

<p>Complex machines are made up of two or more simple machines. (A)</p> Signup and view all the answers

How does a machine primarily assist in performing work?

<p>By simplifying a task to require less effort or a different direction of force. (B)</p> Signup and view all the answers

If a task requires a large force to be applied over a short distance, which modification by a simple machine would effectively make the task easier?

<p>Decrease the force and increase the distance. (B)</p> Signup and view all the answers

A student is designing a complex machine. What should they understand about the simple machines they plan to incorporate?

<p>The simple machines' individual functions must harmonize to achieve the desired outcome. (B)</p> Signup and view all the answers

Why might someone choose to use a complex machine over a simple machine for a particular task?

<p>Complex machines can perform more complicated tasks or a sequence of tasks automatically. (D)</p> Signup and view all the answers

Consider a scenario where someone needs to lift a heavy box onto a truck. Which simple machine could be used to make this task easier, and how does it change the requirements of the work?

<p>Inclined plane; increases the distance over which the force is applied. (D)</p> Signup and view all the answers

How does the use of a bottle opener demonstrate the principle of a simple machine?

<p>It reduces the force required by increasing the distance over which the force is applied. (C)</p> Signup and view all the answers

If a lever has the effort applied between the load and the fulcrum, which class of lever is it?

<p>Third class lever (D)</p> Signup and view all the answers

Which of the following tools exemplifies a third class lever?

<p>Tweezers (A)</p> Signup and view all the answers

What distinguishes a second class lever from other lever types?

<p>The load is positioned between the fulcrum and the effort. (D)</p> Signup and view all the answers

Considering the arrangement of components in a lever system, which placement characterizes a third class lever?

<p>Fulcrum-Effort-Load (D)</p> Signup and view all the answers

Which action best illustrates the use of a third class lever?

<p>Sweeping the floor with a broom. (B)</p> Signup and view all the answers

Which tool operates as a second class lever to enhance mechanical advantage?

<p>Wheelbarrow (D)</p> Signup and view all the answers

In the context of levers, what is the distinguishing characteristic of a wheelbarrow?

<p>Load is between the fulcrum and the effort. (D)</p> Signup and view all the answers

Which of the following activities involves a third class lever?

<p>Picking up sugar cubes with tongs (B)</p> Signup and view all the answers

What is the primary mechanical advantage gained by using a wheelbarrow?

<p>Reducing the amount of effort needed to lift a load (D)</p> Signup and view all the answers

In a third class lever, how is the placement of the effort, load, and fulcrum arranged?

<p>The effort is between the fulcrum and the load. (C)</p> Signup and view all the answers

During the cleaning process with a self-made broom (third class lever), what represents the 'load'?

<p>The dirt or debris being swept. (D)</p> Signup and view all the answers

In the context of using the self-made broom, what applies the effort in this third class lever system?

<p>The hands holding and moving the broom. (B)</p> Signup and view all the answers

When using the self-made broom described, what serves as the fulcrum in this third-class lever?

<p>The point where the broom touches the ground and pivots. (D)</p> Signup and view all the answers

Why is the self-made broom described as a third class lever?

<p>Because the effort is between the fulcrum and the load. (C)</p> Signup and view all the answers

When constructing the self-made broom, what is the purpose of tying the coconut leaf veins or dry grass to the stick?

<p>To create the sweeping component of the broom. (C)</p> Signup and view all the answers

What role does the catapult rubber play in the construction of the self-made broom?

<p>It secures the stick to the sweeping material. (D)</p> Signup and view all the answers

What type of materials are recommended for creating the sweeping component of the self-made broom?

<p>Coconut leaf veins or dry grass. (D)</p> Signup and view all the answers

How does the length of the stick used in making the broom primarily affect its function?

<p>It affects the reach and ease of applying effort. (C)</p> Signup and view all the answers

What is the main advantage of using levers like the self-made broom for tasks such as cleaning?

<p>They increase the distance over which the force is applied, easing the task. (C)</p> Signup and view all the answers

If a lever requires a large effort to move a small load, what can be inferred about the distance between the effort and the fulcrum compared to the distance between the load and the fulcrum?

<p>The distance from the effort to the fulcrum is shorter than the distance from the load to the fulcrum. (C)</p> Signup and view all the answers

How does increasing the length of the handle on a wheelbarrow (where the effort is applied) affect the force needed to lift a load?

<p>It increases turning force at the fulcrum and makes lifting easier. (D)</p> Signup and view all the answers

A person uses a crowbar to lift a heavy rock. If they move the fulcrum closer to the rock, what effect will this have on the amount of force they need to apply to the crowbar?

<p>It will require less force. (D)</p> Signup and view all the answers

Why might a chef choose a longer handled spoon over a shorter handled one when stirring a thick, heavy mixture?

<p>A longer handle reduces the force needed to stir the mixture. (B)</p> Signup and view all the answers

When using a pair of scissors, what adjustment could improve their effectiveness for cutting thick materials?

<p>Moving the pivot point (fulcrum) closer to the blades. (B)</p> Signup and view all the answers

Which of the following scenarios demonstrates the most efficient use of a first class lever to lift a heavy object?

<p>Placing the fulcrum closer to the load. (C)</p> Signup and view all the answers

How does the placement of the fulcrum in a lever affect the trade-off between effort and distance?

<p>A fulcrum closer to the load reduces the required effort but increases the distance the effort must move. (C)</p> Signup and view all the answers

In a second class lever, given a fixed distance between where the effort is applied and where the fulcrum is located, what change would decrease the amount of effort needed to lift a load?

<p>Move the load closer to the fulcrum. (A)</p> Signup and view all the answers

What is the best way to reduce the force needed to open a bottle with a bottle opener (a type of lever)?

<p>Ensure the bottle opener's fulcrum is as close as possible to the bottle cap's edge. (C)</p> Signup and view all the answers

How does the design of a claw hammer, specifically the curvature and length of the claw, enhance its function as a lever for removing nails?

<p>It maximizes the distance between the effort and the fulcrum, reducing the force needed. (B)</p> Signup and view all the answers

What distinguishes simple machines from complex machines?

<p>Simple machines consist of a single mechanism, while complex machines combine multiple simple machines. (D)</p> Signup and view all the answers

Considering the definition provided, which action best exemplifies using a machine to simplify work?

<p>Using a crowbar to lift a heavy stone. (A)</p> Signup and view all the answers

Which of the following tools combines multiple simple machines to perform its function?

<p>A bicycle used for transportation. (B)</p> Signup and view all the answers

If a task requires you to move a heavy object, and all you have available is a simple machine, how would you use a wheelbarrow in such a scenario?

<p>To reduce the amount of force required to move the object by distributing the weight. (B)</p> Signup and view all the answers

How does the use of a bottle opener demonstrate the concept of 'simplifying work'?

<p>By reducing the amount of energy needed to remove the bottle cap, compared to using bare hands. (C)</p> Signup and view all the answers

Why are devices such as spades, hammers, and wheelbarrows categorized together as simple machines?

<p>They each reduce the amount of work needed to accomplish a task with a single action. (A)</p> Signup and view all the answers

In what fundamental way do simple machines 'simplify work' compared to performing tasks without them?

<p>By multiplying the force applied, changing its direction, or increasing the distance over which it is applied, to make the task easier. (D)</p> Signup and view all the answers

A specific task requires separating two tightly fitted wooden boards. Which tool is BEST suited for this, and how should it be applied?

<p>A wedge, by hammering it between the boards to force them apart. (D)</p> Signup and view all the answers

If the angle of a wedge is increased (making it wider), how does this affect the force needed to split a log, assuming the same material and depth of penetration?

<p>It increases the force needed because the wider angle requires more material to be displaced. (B)</p> Signup and view all the answers

Why is it generally easier to split wood with an axe (which combines a wedge and lever action) compared to splitting it with a blunt object of similar weight?

<p>The axe's sharp edge concentrates force, and its shape spreads this force to split the wood, while a blunt object disperses the force. (A)</p> Signup and view all the answers

Consider a scenario where a wedge is used to lift a heavy object slightly. What adjustments could be made to the wedge to reduce the effort needed to lift the object?

<p>Use a smoother material for the wedge to reduce friction. (D)</p> Signup and view all the answers

A person is using a wedge to level a heavy table by inserting it under one of the legs. After hammering the wedge in, they find the table is slightly too high. What adjustment should they make?

<p>Replace the wedge with a thinner one or remove the current one partially. (D)</p> Signup and view all the answers

Which of the following scenarios best illustrates the use of a first class lever?

<p>A seesaw in a playground with one person on each end. (D)</p> Signup and view all the answers

How does the positioning of the load relative to the fulcrum and effort in a second class lever provide a mechanical advantage?

<p>It reduces the effort needed by increasing the distance over which the effort is applied. (A)</p> Signup and view all the answers

Which of the following tasks would be most efficiently performed using a second class lever?

<p>Moving a large pile of soil in a wheelbarrow. (C)</p> Signup and view all the answers

If a lever setup has the fulcrum at one end, the load in the middle, and the effort applied to the other end, which class of lever is being used, and what is its primary effect?

<p>Second class lever; reduces the amount of force needed to lift the load. (A)</p> Signup and view all the answers

How does increasing the length of the handles on a pair of scissors affect their performance as a first class lever?

<p>It decreases the force required to cut, making it easier to cut through thicker materials. (A)</p> Signup and view all the answers

In a first class lever system, how would moving the fulcrum closer to the load affect the amount of effort required to lift that load?

<p>It would decrease the amount of effort required. (B)</p> Signup and view all the answers

What is the main factor that determines the class of a lever?

<p>The relative positions of the fulcrum, load, and effort. (A)</p> Signup and view all the answers

Which modification to a bottle opener (a second class lever) would most likely decrease the amount of effort needed to open a bottle?

<p>Increasing the length of the handle. (C)</p> Signup and view all the answers

Why is it generally easier to use a crowbar to lift a heavy object when a small rock is placed under the crowbar near the object?

<p>The rock serves as a fulcrum, changing the lever system to reduce the effort needed. (A)</p> Signup and view all the answers

How does using a lever, such as a wheelbarrow, change the way work is done?

<p>It changes the direction or magnitude of the force needed to perform the task. (B)</p> Signup and view all the answers

Which scenario best illustrates how levers reduce the force needed to perform a task?

<p>Using a crowbar to lift a heavy stone. (B)</p> Signup and view all the answers

Why might a pair of scissors be considered a complex lever system?

<p>Because each blade acts as a lever, and they work together to amplify the cutting force. (A)</p> Signup and view all the answers

Considering different classes of levers, how does the placement of the fulcrum affect the effort required?

<p>The closer the fulcrum is to the load, the less effort is required, but only in first and second class levers. (B)</p> Signup and view all the answers

How could the effectiveness of a claw hammer be improved when removing a deeply embedded nail?

<p>By using a longer hammer handle. (D)</p> Signup and view all the answers

A person is using a shovel to scoop sand. How does this activity demonstrate the use of a lever?

<p>The shovel acts as a lever, with the fulcrum, effort, and load arranged to enhance lifting. (A)</p> Signup and view all the answers

If a lever system requires significantly more effort than the weight of the load being moved, what could be a possible disadvantage of using this lever?

<p>The lever is increasing the distance over which the effort must be applied. (C)</p> Signup and view all the answers

In what scenario would using a third class lever be most advantageous despite it requiring more effort force?

<p>When needing to precisely control the movement or increase the speed of the load. (C)</p> Signup and view all the answers

When using a bottle opener, how does moving the fulcrum closer to the bottle cap affect the force needed to open the bottle?

<p>It increases the force needed because it reduces the lever arm. (D)</p> Signup and view all the answers

If a lever makes a task 'easier,' what is always fundamentally true about the energy required to complete the task?

<p>The total energy expended remains the same, but the force required is reduced. (D)</p> Signup and view all the answers

In the context of the self-made broom described, how does the placement of the effort between the fulcrum and the load affect the force required for sweeping?

<p>It increases the required effort due to the effort being closer to the fulcrum than the load. (A)</p> Signup and view all the answers

When constructing the self-made broom, how would using a shorter stick affect the experience of sweeping?

<p>It would decrease the range of motion and require more bending over, increasing strain. (B)</p> Signup and view all the answers

While using the self-made broom, if the user applies more force closer to the fulcrum instead of further away, what is the likely outcome?

<p>The sweeping becomes less effective, as more force is required to move the load. (C)</p> Signup and view all the answers

How could the self-made broom be modified to decrease the amount of effort required to sweep, while still functioning as a third class lever?

<p>Move the point where the sweeping component (coconut leaf veins/grass) is attached closer to the effort. (C)</p> Signup and view all the answers

How does the flexibility of the coconut leaf veins or dry grass used in the self-made broom affect its performance in sweeping?

<p>Greater flexibility allows the broom to conform to uneven surfaces, improving contact and sweeping efficiency. (B)</p> Signup and view all the answers

If the catapult rubber on the self-made broom becomes loose, what is the most likely effect on the broom's function as a third class lever?

<p>The broom may become less stable and harder to control, reducing sweeping efficiency. (D)</p> Signup and view all the answers

Imagine the stick used for the self-made broom is replaced with a much heavier metal rod of the same length. How would this change primarily affect the user's experience?

<p>It would increase the effort required to use the broom, leading to faster fatigue. (D)</p> Signup and view all the answers

A student wants to make a more durable version of the described broom. Which of the following modifications would LEAST affect its classification as a third class lever?

<p>Attaching the sweeping head more securely to the stick. (D)</p> Signup and view all the answers

If a different material that is much stiffer than the coconut leaf veins is used for sweeping on the self-made broom, what is the most likely outcome?

<p>The broom will become less effective on uneven surfaces due to reduced contact. (A)</p> Signup and view all the answers

A person finds it difficult to sweep with the self-made broom because the angle between the stick and sweeping head is too acute, causing the head to drag. How can they easily modify the broom to address this issue?

<p>Adjust the angle at which the sweeping head is attached to the stick to make it more obtuse. (B)</p> Signup and view all the answers

There are seven types of simple machines.

<p>False (B)</p> Signup and view all the answers

A lever rotates around a fixed point called a fulcrum.

<p>True (A)</p> Signup and view all the answers

The three main parts of a lever are the fulcrum, effort, and power.

<p>False (B)</p> Signup and view all the answers

Wheelbarrows are examples of levers.

<p>True (A)</p> Signup and view all the answers

In a first class lever, the load is between the fulcrum and the effort.

<p>False (B)</p> Signup and view all the answers

Scissors are an example of a first class lever.

<p>True (A)</p> Signup and view all the answers

In a second class lever, the effort is between the load and the fulcrum.

<p>False (B)</p> Signup and view all the answers

In a third class lever, the load is positioned between the fulcrum and the effort.

<p>False (B)</p> Signup and view all the answers

A broom used for cleaning can act as a third class lever.

<p>True (A)</p> Signup and view all the answers

The effort in a third class lever is always greater than the load.

<p>True (A)</p> Signup and view all the answers

Coconut leaf veins can be used in constructing a third class lever model.

<p>True (A)</p> Signup and view all the answers

A catapult rubber is used to secure the load in a third-class lever model.

<p>False (B)</p> Signup and view all the answers

The fulcrum is positioned between the effort and the load in a third class lever.

<p>False (B)</p> Signup and view all the answers

Third class levers always provide a mechanical advantage greater than 1.

<p>False (B)</p> Signup and view all the answers

A 2.5 m stick is required to demonstrate a third class lever.

<p>False (B)</p> Signup and view all the answers

Dry grass cannot be used to construct a third class lever model.

<p>False (B)</p> Signup and view all the answers

An inclined plane is always perfectly horizontal.

<p>False (B)</p> Signup and view all the answers

Inclined planes can only be used to raise objects.

<p>False (B)</p> Signup and view all the answers

A ladder is an example of an inclined plane.

<p>True (A)</p> Signup and view all the answers

Sloping roads are not considered inclined planes.

<p>False (B)</p> Signup and view all the answers

Inclined planes are sometimes used for loading heavy cargo onto trucks.

<p>True (A)</p> Signup and view all the answers

A wedge has one thick end and one thin, tapering end.

<p>True (A)</p> Signup and view all the answers

An axe is an example of a wheel.

<p>False (B)</p> Signup and view all the answers

Wedges are used to simplify the process of splitting timber.

<p>True (A)</p> Signup and view all the answers

A knife doesn't act as a wedge.

<p>False (B)</p> Signup and view all the answers

A chisel is an example of a lever.

<p>False (B)</p> Signup and view all the answers

In a lever, the fulcrum is always located between the load and the effect.

<p>False (B)</p> Signup and view all the answers

A wheelbarrow is an example of a second class lever.

<p>True (A)</p> Signup and view all the answers

A seesaw demonstrates a third-class lever.

<p>False (B)</p> Signup and view all the answers

A bottle opener is an example of a first class lever.

<p>False (B)</p> Signup and view all the answers

A wooden spoon is used to loosen tools stuck in wood.

<p>False (B)</p> Signup and view all the answers

A hammer is not needed when using a wedge to split wood.

<p>False (B)</p> Signup and view all the answers

The fulcrum is at the center of a first class lever.

<p>True (A)</p> Signup and view all the answers

The effort is at the center of a third class lever.

<p>False (B)</p> Signup and view all the answers

Wedges don't simplify work; they make it harder.

<p>False (B)</p> Signup and view all the answers

Splitting timber is one use of a wedge.

<p>True (A)</p> Signup and view all the answers

An iron spaceship can be used as a wedge.

<p>False (B)</p> Signup and view all the answers

Chopping firewood never requires the use of a wedge.

<p>False (B)</p> Signup and view all the answers

A load is at the centre in the first class lever

<p>False (B)</p> Signup and view all the answers

In a third class lever, the fulcrum is between the load and the effort.

<p>False (B)</p> Signup and view all the answers

Tongs are examples of third class levers.

<p>True (A)</p> Signup and view all the answers

A fishing rod is a second class lever.

<p>False (B)</p> Signup and view all the answers

The wheel of a wheelbarrow acts as the fulcrum.

<p>True (A)</p> Signup and view all the answers

Shovels are third class levers.

<p>True (A)</p> Signup and view all the answers

Second class levers always amplify force but reduce distance.

<p>True (A)</p> Signup and view all the answers

Brooms are examples of second class levers.

<p>False (B)</p> Signup and view all the answers

Effort and load are two main parts of a lever whereas resistance is not.

<p>True (A)</p> Signup and view all the answers

In a first class lever, the effort is between the load and the fulcrum.

<p>False (B)</p> Signup and view all the answers

Crowbars are examples of first class levers.

<p>True (A)</p> Signup and view all the answers

In the second class lever, the load is between the effort and the fulcrum.

<p>True (A)</p> Signup and view all the answers

Wedges are only made of wood.

<p>False (B)</p> Signup and view all the answers

A wedge is used to loosen tools that get stuck.

<p>True (A)</p> Signup and view all the answers

A hammer is not needed when using a wedge.

<p>False (B)</p> Signup and view all the answers

In a third class lever, the effort is located between the fulcrum and the load.

<p>True (A)</p> Signup and view all the answers

A catapult rubber is not one of the materials needed to make a third class lever.

<p>False (B)</p> Signup and view all the answers

The broom in Figure 5 is an example of a first class lever.

<p>False (B)</p> Signup and view all the answers

In the broom example, the load is at the top, where the sweeping occurs.

<p>True (A)</p> Signup and view all the answers

The fulcrum in the broom example is the hand closer to the sweeping end.

<p>False (B)</p> Signup and view all the answers

Load, Effort and Fulcrum can be abbreviated LFE.

<p>False (B)</p> Signup and view all the answers

A 3.0 m stick is required to make the third class lever.

<p>False (B)</p> Signup and view all the answers

A pair of scissors is an example of a third class lever.

<p>False (B)</p> Signup and view all the answers

Third class levers always increase the force applied.

<p>False (B)</p> Signup and view all the answers

The effort in the broom example, is where you place your hand to use the broom.

<p>True (A)</p> Signup and view all the answers

Levers are designed to complicate work.

<p>False (B)</p> Signup and view all the answers

A wheelbarrow is an example of a lever used for carrying loads.

<p>True (A)</p> Signup and view all the answers

A claw hammer is used for pushing nails into wood.

<p>False (B)</p> Signup and view all the answers

Scissors are a type of lever used for cutting.

<p>True (A)</p> Signup and view all the answers

A knife is a type of lever.

<p>False (B)</p> Signup and view all the answers

A bottle opener is considered a type of lever.

<p>True (A)</p> Signup and view all the answers

A spanner is used for scooping sand.

<p>False (B)</p> Signup and view all the answers

A shovel is used for digging the land.

<p>True (A)</p> Signup and view all the answers

A machete is used for cutting firewood.

<p>True (A)</p> Signup and view all the answers

A fishing hook is a type of lever.

<p>False (B)</p> Signup and view all the answers

A bottle opener exemplifies a device designed to complicate work, necessitating the application of greater force than would be required without it.

<p>False (B)</p> Signup and view all the answers

A complex machine consists of one or more simple machines working together.

<p>True (A)</p> Signup and view all the answers

A pair of scissors, a seesaw, and a pulley system are classified as complex machines due to their intricate designs and numerous moving components.

<p>False (B)</p> Signup and view all the answers

Machines are exclusively electrical devices designed to automate tasks, and exclude manually operated tools.

<p>False (B)</p> Signup and view all the answers

The primary distinction between simple and complex machines lies solely in their size, with simple machines being smaller and less powerful.

<p>False (B)</p> Signup and view all the answers

A wheelbarrow exemplifies a second class lever where the effort is situated between the load and the fulcrum.

<p>False (B)</p> Signup and view all the answers

In a first class lever, the effort is positioned between the fulcrum and the load.

<p>False (B)</p> Signup and view all the answers

Using your bare hand to try and open a bottle is an example of using a complex machine.

<p>False (B)</p> Signup and view all the answers

Spades and shovels are examples of third class levers.

<p>False (B)</p> Signup and view all the answers

Spades, hammers and wheelbarrows are examples of complex machines.

<p>False (B)</p> Signup and view all the answers

Levers, inclined planes, gears, pulleys, screws, and wedges are the six simple machines.

<p>False (B)</p> Signup and view all the answers

The primary purpose of a fulcrum in a lever system is to minimize the amount of effort required to move a load.

<p>False (B)</p> Signup and view all the answers

A claw hammer is an example of a first class lever.

<p>True (A)</p> Signup and view all the answers

Bottle openers operate as second class levers due to the fulcrum being located between the effort and the load.

<p>False (B)</p> Signup and view all the answers

The mechanical advantage of a lever is solely determined by the material from which it is constructed.

<p>False (B)</p> Signup and view all the answers

In all lever systems, increasing the distance between the effort and the fulcrum always decreases the amount of force required to move the load.

<p>False (B)</p> Signup and view all the answers

An inclined plane is most effective when used perpendicular to the object being moved.

<p>False (B)</p> Signup and view all the answers

A pulley is an example of an inclined plane used for raising or lowering objects.

<p>False (B)</p> Signup and view all the answers

A wedge works by applying force to a small area to create a splitting effect.

<p>True (A)</p> Signup and view all the answers

If a carpenter's plane were modified to have a completely flat, non-sloping surface, it would still function effectively as an inclined plane.

<p>False (B)</p> Signup and view all the answers

Using a staircase instead of a ladder to reach the second floor of a building reduces the amount of work needed to overcome gravity.

<p>False (B)</p> Signup and view all the answers

In a second class lever, the fulcrum is always positioned between the load and the effort.

<p>False (B)</p> Signup and view all the answers

A wheelbarrow exemplifies a second class lever due to the effort being applied between the load and the fulcrum.

<p>False (B)</p> Signup and view all the answers

Third class levers have the load positioned between the effort and the fulcrum.

<p>False (B)</p> Signup and view all the answers

Tongs exemplify a third class lever because the effort is applied between the load and the fulcrum.

<p>True (A)</p> Signup and view all the answers

The primary mechanical advantage of a third class lever is to increase the force applied to a load at the expense of distance.

<p>False (B)</p> Signup and view all the answers

A fishing rod is an example of a second class lever because the fulcrum is at one end, the load (fish) is at the other, and the effort is applied in the middle.

<p>False (B)</p> Signup and view all the answers

Tweezers operate as a third class lever, requiring a smaller force input compared to the resistance force exerted on a small object.

<p>False (B)</p> Signup and view all the answers

In both second and third class levers, the position of the fulcrum remains constant, while the load and effort positions can be interchanged.

<p>False (B)</p> Signup and view all the answers

Brooms are designed as third class levers, where the effort is applied nearest to the fulcrum in order to maximize the sweeping force.

<p>False (B)</p> Signup and view all the answers

Second class levers, like wheelbarrows, always provide a mechanical advantage where the effort required is less than the weight of the load.

<p>True (A)</p> Signup and view all the answers

In a third-class lever, the fulcrum is always positioned between the load and the effort.

<p>False (B)</p> Signup and view all the answers

When using a broom as a third-class lever, the force applied by your hands represents the effort.

<p>True (A)</p> Signup and view all the answers

The length of the stick in the provided activity directly affects the amount of effort needed to move a load.

<p>True (A)</p> Signup and view all the answers

Using thicker wire in the broom-making activity will decrease the stability of the lever system.

<p>False (B)</p> Signup and view all the answers

In the broom activity, the point where the broom touches the ground represents the effort.

<p>False (B)</p> Signup and view all the answers

Replacing the catapult rubber with a rigid metal bar would improve the broom's functionality as a third-class lever.

<p>False (B)</p> Signup and view all the answers

If the load is moved closer to the fulcrum in a third-class lever, the required effort to move the load increases.

<p>False (B)</p> Signup and view all the answers

Third-class levers are designed to multiply the force applied, making it easier to move heavy objects.

<p>False (B)</p> Signup and view all the answers

The only purpose of a third-class lever is to clean the environment.

<p>False (B)</p> Signup and view all the answers

Changing the material of the stick from wood to a lighter plastic will change the class of the lever.

<p>False (B)</p> Signup and view all the answers

What happened to the pieces of paper when they were first put into the pot of water?

<p>They remained at the bottom of the pot. (C)</p> Signup and view all the answers

What happens to water molecules when water is heated?

<p>They gain heat energy and move more rapidly. (D)</p> Signup and view all the answers

What is the name of the heat transfer process demonstrated in the experiment?

<p>Convection (D)</p> Signup and view all the answers

During the experiment, which of the following was used to measure the temperature of the water?

<p>A thermometer (A)</p> Signup and view all the answers

What visible change in the pot indicated that the water was being heated effectively?

<p>The pieces of paper started moving. (C)</p> Signup and view all the answers

What is the purpose of a scientific experiment?

<p>To explore and understand natural phenomena (C)</p> Signup and view all the answers

What is the first step in the expansion and contraction of solid materials experiment?

<p>Pass the metal ball through the metal ring. (D)</p> Signup and view all the answers

What should you observe before heating the metal ball in the experiment?

<p>The metal ball goes exactly through the ring. (B)</p> Signup and view all the answers

What is needed to provide heat in the expansion experiment?

<p>A source of heat (C)</p> Signup and view all the answers

What is the expected outcome when the heated metal ball is passed through the ring?

<p>The ball does not pass through the ring. (A)</p> Signup and view all the answers

What is the best way to cool the metal ball quickly after heating it?

<p>Run it under cold water. (D)</p> Signup and view all the answers

What safety precaution is important when conducting the expansion of solid materials experiment?

<p>All of the above. (D)</p> Signup and view all the answers

What material is used in Experiment 4 to demonstrate heat transfer?

<p>Iron bar (B)</p> Signup and view all the answers

What happens to the wax in Experiment 4 when heat is applied to the iron bar?

<p>It melts (A)</p> Signup and view all the answers

What is the source of heat mentioned for Experiment 4?

<p>A Bunsen burner (D)</p> Signup and view all the answers

What kind of heat transfer is demonstrated by Experiment 4?

<p>Conduction (B)</p> Signup and view all the answers

What is placed under the iron bar in Experiment 4?

<p>A piece of wood (A)</p> Signup and view all the answers

What is the purpose of Experiment 5?

<p>To observe how heat travels through water (D)</p> Signup and view all the answers

Which material is heated in Experiment 5?

<p>Water (D)</p> Signup and view all the answers

What item is used to measure temperature in Experiment 5?

<p>Thermometer (B)</p> Signup and view all the answers

What is added to the pot in Experiment 5 besides water?

<p>Small pieces of paper (A)</p> Signup and view all the answers

What is the expected observation in Experiment 4?

<p>The wax melts (A)</p> Signup and view all the answers

What happens to the balloon when the bottle is placed in hot water?

<p>It expands. (D)</p> Signup and view all the answers

What is the effect of heating air in a closed container?

<p>The air expands. (B)</p> Signup and view all the answers

What material is tied to the top of the plastic bottle in the experiment?

<p>A balloon. (A)</p> Signup and view all the answers

What is used to tie the balloon on top of the plastic bottle?

<p>A thread (C)</p> Signup and view all the answers

What is the first step of the experiment?

<p>Tie the balloon to the bottle. (D)</p> Signup and view all the answers

What is heated in the pot during the experiment?

<p>Water (D)</p> Signup and view all the answers

What happens to the volume of air when it is heated?

<p>It increases. (D)</p> Signup and view all the answers

What is the correct order of actions for the experiment?

<p>Fill balloon, then hot water, then cold water. (D)</p> Signup and view all the answers

What happens to the size of a metal ball when it is heated?

<p>It expands and increases in size. (C)</p> Signup and view all the answers

After heating a metal ball and then letting it cool, what happens to its size?

<p>It goes back to its original size, contracting. (A)</p> Signup and view all the answers

What is the correct observation when a heated metal ball cannot pass through a ring?

<p>The metal ball has expanded. (B)</p> Signup and view all the answers

What should happen to the metal ball for it to pass through the metal ring after it's been heated?

<p>It should be cooled down. (A)</p> Signup and view all the answers

What materials are needed to observe the expansion of water when heated?

<p>Coloured water, bottle, and heat source. (D)</p> Signup and view all the answers

What is the first step in the procedure to observe the expansion and contraction of liquids?

<p>Fill the glass bottle with colored water. (A)</p> Signup and view all the answers

What happens to water when it is cooled?

<p>It contracts. (C)</p> Signup and view all the answers

What is the purpose of using colored water in the experiment?

<p>To see the water expand and contract more clearly. (C)</p> Signup and view all the answers

What can be used as a source of heat in the experiment?

<p>A Bunsen burner. (C)</p> Signup and view all the answers

What role does the vacuum play in a thermos flask to minimize heat transfer?

<p>It prevents heat transfer by conduction and convection. (B)</p> Signup and view all the answers

Why is the inner chamber of a thermos flask covered with silver?

<p>To reduce heat loss through radiation. (C)</p> Signup and view all the answers

Why are the walls of the outer part of a thermos flask made of glass?

<p>To reduce heat loss by conduction. (C)</p> Signup and view all the answers

In measuring body temperature using a thermometer, what part of the thermometer indicates the temperature reading?

<p>The number at the upper limit of the mark of the internal line of the thermometer. (C)</p> Signup and view all the answers

What is the primary function of the rubber support at the bottom of a thermos flask?

<p>To provide stability and prevent breakage. (D)</p> Signup and view all the answers

In the described experiment, what evidence suggests that water molecules are not initially free to move?

<p>The pieces of paper remain at the bottom of the pot. (B)</p> Signup and view all the answers

What causes water molecules to move more rapidly during the experiment?

<p>Putting the pot on the stove. (C)</p> Signup and view all the answers

Which process is demonstrated when heat is transferred through the movement of water molecules?

<p>Convection (C)</p> Signup and view all the answers

What happens to the temperature of the water as heat energy is gained?

<p>The temperature increases. (B)</p> Signup and view all the answers

What role do the pieces of paper play in this experiment?

<p>They indicate the movement of water molecules. (D)</p> Signup and view all the answers

How does the experiment demonstrate that water molecules gain heat energy?

<p>By moving more rapidly when heated. (C)</p> Signup and view all the answers

What would likely happen if oil was used instead of water in the same experiment?

<p>Convection currents would form differently due to oil's different thermal properties. (D)</p> Signup and view all the answers

If the experiment was conducted using a metal pot instead of a glass pot, how would the results likely differ?

<p>The water would heat up more quickly due to better heat conduction of metal. (B)</p> Signup and view all the answers

How does increasing the volume of water in the pot likely affect the outcome of the experiment?

<p>The rate of convection would decrease, as more energy is needed to heat a larger volume. (A)</p> Signup and view all the answers

During Experiment 1, if the metal ball does not pass through the ring at room temperature, what is the most likely reason?

<p>The ball is too large or the ring is too small. (D)</p> Signup and view all the answers

In Experiment 1, predict what would happen if, after heating the metal ball, you cooled the ring instead of trying to pass the heated ball through it.

<p>The ball would pass through the ring more easily due to the ring's contraction. (B)</p> Signup and view all the answers

What property of solids is Experiment 1 designed to demonstrate?

<p>Solids expand when heated and contract when cooled. (C)</p> Signup and view all the answers

Besides the materials listed, what additional safety precaution should be considered when performing Experiment 1?

<p>Wearing safety goggles to protect from potential flame or heat-related hazards. (C)</p> Signup and view all the answers

Imagine instead of a metal ball and ring, gas is trapped inside a container with a piston. How would heating the container affect the piston's position, assuming the gas can expand freely?

<p>The piston would move up, increasing the volume. (B)</p> Signup and view all the answers

How would the results of Experiment 1 change if the metal ball and ring were made of different metals with significantly different coefficients of thermal expansion?

<p>The metal with a higher coefficient of expansion would expand more for the same temperature change. (B)</p> Signup and view all the answers

Applying the principles of Experiment 1, why are small gaps left between sections of railway tracks and bridge expansion joints?

<p>To allow for the tracks and bridges to expand in hot weather without causing buckling or deformation. (A)</p> Signup and view all the answers

In the 'Heat transfer through air' experiment, what crucial step allows for observing the heat transfer process?

<p>Leaving the wet cloth in the sun. (C)</p> Signup and view all the answers

What is the primary visible outcome that indicates heat transfer has occurred in the 'Heat transfer through air' experiment?

<p>The cloth dries. (D)</p> Signup and view all the answers

According to the 'Heat transfer through air' experiment, how does heat from the sun reach the wet cloth?

<p>Radiation through the air. (D)</p> Signup and view all the answers

In the 'Reducing heat loss' experiment, why is it important to examine the materials of both the outer and inner parts of the thermos flask?

<p>To understand how the flask minimizes heat transfer. (B)</p> Signup and view all the answers

What property of the screw top/stopper material of a thermos flask is most important for minimizing heat loss?

<p>Its ability to insulate. (A)</p> Signup and view all the answers

In the 'Heat transfer through air' experiment, if the wet cloth was placed in a dark, enclosed room instead of the sun, how would the results differ, and why?

<p>It would dry much slower due to the absence of direct radiation. (C)</p> Signup and view all the answers

Considering the principles demonstrated in the thermos flask experiment, which modification would LEAST improve a thermos' ability to prevent heat loss?

<p>Making the outer container from a thicker, more conductive metal. (D)</p> Signup and view all the answers

If the 'Heat transfer through air' experiment were conducted on a windy day versus a still day, how might the results differ, and what principle would this illustrate?

<p>Drying would be faster on a windy day, illustrating the principle of convection. (C)</p> Signup and view all the answers

In the context of the 'Reducing heat loss' experiment, what is the purpose of the vacuum between the inner and outer walls of a thermos flask?

<p>To prevent heat transfer through conduction and convection. (C)</p> Signup and view all the answers

Based on both experiments, how do radiation, conduction, and convection relate to the transfer and retention of heat?

<p>Radiation primarily transfers heat through air, while conduction and convection are minimized in devices designed to retain heat. (B)</p> Signup and view all the answers

What material typically makes up the outer part of a thermos flask?

<p>Plastic or metal (D)</p> Signup and view all the answers

Which property is most important for the material used to make the screw stopper or lid of a thermos flask?

<p>Poor conductor of heat (C)</p> Signup and view all the answers

Why is a vacuum created between the inner and outer parts of a thermos flask?

<p>To prevent heat transfer (A)</p> Signup and view all the answers

What is the primary reason for coating the glass wall of the inner chamber with reflective silver?

<p>To reflect heat radiation (B)</p> Signup and view all the answers

In a thermos flask, which component minimizes heat transfer by conduction and convection simultaneously?

<p>The vacuum between the walls (C)</p> Signup and view all the answers

If a thermos flask were made without a vacuum between its walls, what would be the most likely consequence?

<p>Decreased temperature retention (A)</p> Signup and view all the answers

Which statement best describes the combined effect of the vacuum and the reflective silver coating in a thermos flask?

<p>They minimize all forms of heat transfer. (D)</p> Signup and view all the answers

How would replacing the plastic lid of a thermos flask with a metal lid likely affect its performance?

<p>Decrease its ability to maintain temperature due to conduction. (A)</p> Signup and view all the answers

What would be the most noticeable change if the reflective coating on the inner glass wall of a thermos flask was removed?

<p>The flask would lose heat more quickly. (A)</p> Signup and view all the answers

A manufacturer is trying to reduce production costs of a thermos. Which of these modifications would most significantly reduce the thermos' ability to maintain temperature?

<p>Removing the reflective coating from the inner glass wall. (B)</p> Signup and view all the answers

When a metal ball is heated, it contracts.

<p>False (B)</p> Signup and view all the answers

When the metal ball was cooled, it was able to pass through the ring because it contracted and decreased in size.

<p>True (A)</p> Signup and view all the answers

The aim of the second experiment is to observe the contraction of water when it is heated and the expansion of water when it is cooled.

<p>False (B)</p> Signup and view all the answers

A Bunsen burner can be used as a source of heat in the experiment.

<p>True (A)</p> Signup and view all the answers

The metal ball experiment demonstrates thermal expansion and contraction.

<p>True (A)</p> Signup and view all the answers

Normal water is used to fill the glass bottle in the second experiment.

<p>False (B)</p> Signup and view all the answers

Before heating the metal ball, it could pass through the ring.

<p>True (A)</p> Signup and view all the answers

In the experiment, the wet cloth dries due to heat transfer through the air.

<p>True (A)</p> Signup and view all the answers

The process of heat transfer from the sun to the cloth is called convection.

<p>False (B)</p> Signup and view all the answers

A thermometer is required to observe the heat transfer through air.

<p>False (B)</p> Signup and view all the answers

A thermos flask is designed to prevent heat transfer.

<p>True (A)</p> Signup and view all the answers

The outer part of a thermos flask is irrelevant to its ability to prevent heat loss.

<p>False (B)</p> Signup and view all the answers

When water is heated, it expands.

<p>True (A)</p> Signup and view all the answers

When water is cooled, it contracts.

<p>True (A)</p> Signup and view all the answers

In the experiment, the water level in the glass tube decreases when the bottle is heated.

<p>False (B)</p> Signup and view all the answers

The experiment in the text aims to observe the expansion and contraction of liquids.

<p>True (A)</p> Signup and view all the answers

Normal water is used in the water bath during the expansion and contraction experiment.

<p>True (A)</p> Signup and view all the answers

A plastic bottle is best to use when observing the expansion and contraction of water.

<p>False (B)</p> Signup and view all the answers

Air does not expand or contract.

<p>False (B)</p> Signup and view all the answers

Coloured water is used to make the water level more visible in the glass tube.

<p>True (A)</p> Signup and view all the answers

A thread and matchbox are materials needed to see expansion and contraction of water.

<p>False (B)</p> Signup and view all the answers

The aim of Experiment 4 is to examine heat transfer through an iron bar.

<p>True (A)</p> Signup and view all the answers

Wood is used to directly heat the wax in Experiment 4.

<p>False (B)</p> Signup and view all the answers

A thermometer is a required material for Experiment 4.

<p>False (B)</p> Signup and view all the answers

In Experiment 4, the wax melts because heat travels through the iron bar.

<p>True (A)</p> Signup and view all the answers

Experiment 4 demonstrates that heat transfer in solids occurs via convection.

<p>False (B)</p> Signup and view all the answers

Experiment 5 aims to observe how heat travels through oil.

<p>False (B)</p> Signup and view all the answers

Small pieces of paper are used in Experiment 5.

<p>True (A)</p> Signup and view all the answers

A spirit lamp can be used as the heat source in both Experiment 4 and Experiment 5.

<p>True (A)</p> Signup and view all the answers

The experiment about heat transfer through liquids uses an iron bar.

<p>False (B)</p> Signup and view all the answers

Conduction is the method of heat transfer observed in Experiment 5

<p>False (B)</p> Signup and view all the answers

In the experiment, a balloon is tied to the bottom of a plastic bottle.

<p>False (B)</p> Signup and view all the answers

The pot should be placed on the table before turning on the stove.

<p>False (B)</p> Signup and view all the answers

Placing the bottle in hot water causes the balloon to expand.

<p>True (A)</p> Signup and view all the answers

Dipping the bottle in warm water makes the balloon bigger.

<p>False (B)</p> Signup and view all the answers

When air is cooled, it expands.

<p>False (B)</p> Signup and view all the answers

This experiment demonstrates the expansion and contraction of liquids.

<p>False (B)</p> Signup and view all the answers

The volume of air decreases when it is heated.

<p>False (B)</p> Signup and view all the answers

A thread is used to tie the balloon to the plastic bottle.

<p>True (A)</p> Signup and view all the answers

The balloon contracts when the bottle is placed in the sunshine.

<p>False (B)</p> Signup and view all the answers

Expansion refers to an increase in the temperature of a material.

<p>False (B)</p> Signup and view all the answers

Flashcards

Simple Machines

Devices used to make work easier.

Machine

Any device that reduces the effort needed to perform a task.

Simple Machines

Machines with few parts that perform a single task.

Complex machine

Machines made of two or more simple machines.

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Lever

A tool that pivots around a fixed point (fulcrum) to multiply force.

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Inclined plane

A flat surface set at an angle used to help raise or lower objects.

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Wedge

A triangular object that is used to separate or split objects.

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What are simple machines?

Simple machines are basic mechanical devices that multiply force or change its direction.

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How many types of simple machines are there?

There are six: levers, inclined planes, wedges, wheels and axles, pulleys, and screws.

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What is a lever?

A rigid bar that pivots around a fixed point (fulcrum) to multiply force.

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What is a fulcrum?

The fixed point around which a lever rotates.

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What is effort in a lever?

The force applied to a lever.

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What is load in a lever?

The object being moved or lifted by a lever.

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First class lever

The fulcrum is located between the load and the effort.

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Examples of first class levers

Examples include scissors, crowbars and beam balances.

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Second class lever

The load is between the fulcrum and the effort.

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Fulcrum

The point around which a lever pivots or turns.

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Effort

The force applied to a lever to move a load.

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Load

The object being moved or lifted by a lever.

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Third Class Lever

Effort is between the fulcrum and the load.

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Wheelbarrow

A wheelbarrow allows you to carry heavy items with less effort.

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Claw Hammer

A claw hammer uses leverage to remove nails from wood.

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Scissors

Scissors use two levers to cut materials.

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Examples of Inclined Planes

Examples of inclined planes include ladders, sloping roads, and hills.

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Uses of Inclined Planes

Simple machines that simplifies lifting and lowering objects.

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Axes as Wedges

An axe is used for splitting wood apart

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Examples of Wedges

The sharpened edge of a knife and chisels

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Purpose of a Wedge

A simple machine used to split or separate objects.

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Roads as Inclined Planes

A sloping road is an example of an inclined plane.

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Ladders as Inclined plane

Ladders are examples of inclined plane.

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Inclined Planes for Loading

Inclined planes can simplify loading cargo onto trucks.

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What are machines?

Devices used to simplify tasks.

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What is a machine?

A device that simplifies work.

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What is a Simple Machine?

Machines with few parts that perform a single task.

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What is a Complex Machine?

Machines made of two or more simple machines.

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Examples of Simple Machines

Spades, hammers, wheelbarrows, openers, scissors, seesaws, pulleys, beam balances, crowbars, and spanners.

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Examples of Complex Machines

Sewing machines and bicycles are complex machines.

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Function of a Bottle Opener

A bottle opener helps remove bottle caps effortlessly.

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Load Position (2nd Class)

The placement of the load is between the fulcrum and the effort.

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Effort Position (3rd Class)

The effort is applied between the load and the fulcrum.

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Tongs and Tweezers

Tools that have handles that meet and are of third class levers.

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Broom

A tool used for sweeping.

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Fishing rod

Equipment used for catching fish.

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Shovel

A tool with a wide scoop.

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What is a Wedge?

A triangular tool used to split or separate objects by applying force along its length.

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Wooden Wedge

A triangular-shaped tool, often made of wood or iron, used for splitting materials.

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Wedge Use

Using a wedge involves inserting it into a material and applying force (e.g., with a hammer).

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Wedge Activity

A task or activity used to show how a wedge makes work easier.

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Wedge Simple Machine

A device that multiplies force when forced into a material.

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Broom as Third Class Lever

A broom is a third class lever because the effort is between the fulcrum and the load

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Broom Creation Materials

Coconut leaf veins or dry grass are tied to a stick to make a broom

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Catapult Rubber's Role

A catapult rubber fixes a stick to coconut leaf veins to form a broom

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Effort in Brooming

The force you apply to the broom

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Load in Brooming

The part of the broom touching the floor

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Fulcrum in Brooming

The hand at the top of the broom/stick

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Uses of Levers

Tools that reduce effort needed to perform tasks.

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Application of levers

Opening soda bottles.

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Levers use

Lifting things.

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Spanner

Tightening bolts.

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Simple Machine Examples

Spades, hammers, wheelbarrows, openers, etc.

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Complex Machine Examples

Sewing machines and bicycles.

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Bottle Opener Function

Used to simplify work.

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How wedges simplify work

Wedges make work easier by concentrating force at a narrow point.

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Wedge in chopping wood

A simple machine (wedge) is used to loosen a tool that is stuck during chopping of firewood.

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Wedge to split timber

A simple machine (wedge) used for splitting timber or a log.

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What is the Fulcrum?

The fixed point around which a lever rotates.

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How many simple machines?

Six: levers, inclined planes, wedges, wheels and axles, pulleys, and screws.

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What is Effort?

The force applied to a lever.

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What is Load?

The object being moved or lifted by a lever.

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Examples of second class levers

Wheelbarrows and bottle openers.

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Lever Function

Levers make tasks easier by multiplying force or changing direction.

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Wheelbarrow Use

A wheelbarrow reduces the effort needed to carry heavy loads by using a wheel and lever system.

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Scissors as Levers

Scissors employ two levers to cut materials. The pivot point multiplies your cutting force.

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Bottle Opener Lever

A bottle opener leverages force to easily remove a bottle cap.

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Third class lever definition

The effort is applied between the fulcrum and the load.

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Broom's Fulcrum?

The hand at the top of the broom/stick.

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Broom's Load?

The part of the broom touching the floor.

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Broom's Effort?

The force you apply to the broom.

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Third Class Lever Identification

Where are the load, effort and fulcrum located?

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Broom construction step 1

Tie the coconut leaf veins or dry grass using two pieces of wood and wire

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Broom construction step 2

Insert the stick into the coconut leaf veins

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Broom construction step 3

Use the catapult rubber to fix the stick into the coconut leaf veins or dry grass to form a broom.

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Broom construction step 4

Clean the environment using the broom you have made

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What is a Third Class Lever?

The effort is between the fulcrum and the load.

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Examples of Third Class Levers

Brooms, fishing rods, and tweezers are third class levers

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What is a broom?

A tool used for sweeping floors

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Broom Effort

The force applied when sweeping

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Broom Fulcrum

The hand at the top of the broom

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Wedge definition

A piece of wood or iron with one end thick and the other tapering to a thin edge

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Wedge and Axe

The iron part of the axe.

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Axe Function

Simple machine to simplify splitting of timber or firewood.

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How Wedge Works

Placing it between the materials.

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Ladder Use

Ladder simplifies moving to higher/lower levels.

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Using a Wedge

Apply the wedge by placing it into the chopped part of the log and hitting it with a hammer or mallet to split the wood.

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Axe as a Wedge

Chopping logs with an axe uses the principle of a wedge to apply force.

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What is a wooden wedge?

A triangular-shaped tool used for splitting or separating materials.

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Wedge main use

To split open a wooden log more easily using a wedge.

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Fulcrum is?

The fixed point around which a lever pivots.

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Types of simple machines

Simple machines are basic mechanical devices that multiply force or change its direction. There are six types.

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Wheelbarrow as Lever

A simple machine where the load is between the fulcrum and effort.

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Tweezers

A tool used for picking up small objects.

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Tongs

A tool used with the principle of third class lever.

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Bottle Opener Example

Opening a soda bottle using a bottle opener.

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Spanner for Bolts

Changing a bolt nut with a spanner.

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Wooden spoon

A lever that can be constructed easily in our environment

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Broom Making Material

Coconut leaf veins or dry grass tied to a stick

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Catapult Rubber (Broom)

Used to secure the stick to the sweeping part of the broom.

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Broom Lever Advantage

Sweeping is made easier because less force is needed to more the same load.

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Lever Usage Purpose

To minimize the amount of force applied to the broom for a given task

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Homemade Broom Step 1

First, secure the sweeper to the broomstick

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Homemade Broom Step 2

Second, maneuver the broom to clean the surrounding area

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Bottle Opener

A bottle opener helps remove bottle caps.

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Inclined Plane Use

A tilted surface used to raise or lower objects.

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Wedge Function

Simplifies work by separating materials.

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Effort (Lever)

The force applied to a lever to move a load.

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Load (Lever)

The object being moved or lifted by a lever.

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Classes of levers

There are three classes

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What is the load?

The object being moved or lifted by a lever.

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Role of catapult rubber

Fixes the stick to coconut leaf veins to form a broom

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Broom in third class levers

Common brooms represent third class levers

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Examples: Third Class

Tools such as tongs, brooms, fishing rods, tweezers and shovels.

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Broom (Lever)

Applies force to sweep away dirt.

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Tweezers (Lever)

Grips and manipulates objects.

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Fishing Rod (Lever)

Catches fish by applying force along the rod.

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Shovel (Lever)

A tool to pick up large amounts of substance

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Tongs (Lever)

Used to grab things at a distance.

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Wheelbarrow: lever

How does the location of the load relates to the fulcrum and the effort?

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Lever Defined

A simple machine consisting of a rigid bar that pivots around a fixed point (fulcrum).

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What is an inclined plane?

A flat, sloping surface used to raise or lower objects.

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Wheelbarrow Lever Class

A lever with the load in the middle.

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What is a 'load'?

The object or weight being moved or lifted by a lever.

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Example of 2nd class lever?

A bottle opener and a wheelbarrow.

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What is an Axe?

A simple machine used to simplify splitting of timber or firewood.

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What defines a 3rd class lever?

A lever where the effort is between the fulcrum and load.

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Broom: What is the Fulcrum?

The hand at the top of the broom.

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Broom: What is the Effort?

The force you apply when sweeping.

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Broom: What is the Load?

The part of the broom touching the floor.

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Broom: What do I need?

Load, Effort, Fulcrum.

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Broom & Third class lever?

Force applied between fulcrum and load.

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What is catapult rubber's role?

Fixes stick to coconut leaf veins.

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What is a broom used for?

Sweeping floors.

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What is broom construction step 4?

To clean the environment using the broom

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What is broom construction step 2?

Insert the stick into the coconut leaf veins

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Function of Inclined Planes

Ladders, sloping roads, and ramps facilitate easier lifting and lowering of objects.

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Expansion

The process where materials increase in volume when heated.

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Contraction

The process where materials decrease in volume when cooled.

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Experiment 1 Aim

To observe how a metal ball's size changes when heated or cooled.

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Materials for Experiment 1

A metal ring, metal ball, heat source (Bunsen burner), clamp, and stand.

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Step 1: Metal Ball and Ring

Pass a metal ball through a ring at room temperature.

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Step 2: Heat the ball

Heat the metal ball.

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Step 3: Test fit after heating

Try to pass the heated ball through the metal ring again.

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Thermal Expansion

When a metal ball is heated, its size increases.

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Thermal Contraction

When a metal ball is cooled, its size decreases.

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Metal Response to Temperature

Metals change size with temperature changes; they expand when heated and contract when cooled.

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Liquid Expansion

Liquids, like water, increase in volume when heated.

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Liquid Contraction

Liquids decrease in volume when cooled.

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Metal Ball Experiment

An experiment to see what happens to a metal ball when heated.

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Water Expansion Experiment

An experiment demonstrating volume changes in water when heated and cooled.

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Air Expansion

When heated, air expands, increasing in volume.

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Air Contraction

When cooled, air contracts, decreasing in volume.

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Heating and Cooling Effect

Heating causes expansion; cooling causes contraction.

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Balloon in Hot Water

In hot water, the air inside the balloon expands, inflating the balloon.

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Balloon in Cold Water

In cold water, the air inside the balloon contracts, causing it to deflate.

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Gas Expansion vs. Solids/Liquids

Gases expand more than solids or liquids because their molecules are more free to move.

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Volume Change with Temperature

The volume increases when heated, causing expansion. The volume decreases when cooled, causing contraction.

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Expansion Experiment

Tie a balloon to a bottle, heat the bottle, and the balloon will inflate.

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Conduction

The process where heat transfers through a material without the material itself moving.

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Heat Transfer in Solids

Heat transfer through a solid involving direct contact.

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Iron

An example of a material through which heat transfers easily.

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Melting

A change of state from solid to liquid due to increased heat.

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Heat Source

A source of energy that provides heat.

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Experiment

A demonstration to prove a scientific concept.

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Heat transfer in liquids

The process where heat travels through a liquid.

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Pot

A container used to hold liquids for heating or cooking.

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Thermometer

Used to measure the temperature of liquids.

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Water Molecules

When heated, water molecules gain energy and move more freely.

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Heat Transfer in Water

The transfer of heat energy within a fluid like water.

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Heated Liquid Molecules

Molecules in liquids gain the energy to move more freely when heated. This is convection.

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Convection Explanation

The movement of heat through fluids due to density differences.

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Thermos Flask

A device that prevents heat loss using a vacuum and reflective surfaces.

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Silvered Surface (Thermos)

Reduces heat loss by reflecting heat back into the container

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Vacuum (Thermos)

Minimizes heat transfer by conduction and convection.

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Thermos Heat Prevention

Process that uses heat transfer to maintain temperature

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Solid Materials

Materials that maintain their shape and volume.

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Metal Ball

The metal object that can be heated in the experiment.

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Metal Ring

A circular metal object through which the ball may or may not pass.

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Clamp and Stand

A device used for supporting equipment during the experiment.

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Molecular Motion

The random motion of molecules in a substance.

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Energy

The capacity to do work or cause change.

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Heat Energy

Energy possessed by a substance due to the movement of its molecules.

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Gain Heat Energy

To gain heat energy means to absorb heat.

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Heat Transfer

The movement of heat from one place to another.

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Water Molecules & Heat

Molecules in water gaining heat energy and moving more rapidly.

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Convection in Liquids

The movement of molecules due to heat transfer in liquids.

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Water Molecules at Rest

Molecules of water are not free to move when heat isn't applied.

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Radiation

Heat transfer through air via radiation.

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Evaporation by Radiation

The drying of wet cloth in sunlight.

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External Parts

An outer layer providing protection.

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Stopper Material

A usually non-metallic material that reduces heat loss.

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Outer Container

The outermost part of the thermos flask vessel.

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Heat Loss

The process of losing heat to the surroundings

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Inner Chamber

The inner part of the thermos flask.

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Heat Transfer by Radiation

Heat transfer by electromagnetic waves, no medium needed.

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Thermos Flask Inner Chamber Colour?

Reflective silver to minimise heat transfer via radiation.

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Thermos Flask Outer Part Material?

Plastic or Metal

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Thermos Flask Stopper Material?

Poor conductors of heat (e.g., wood or plastic).

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Vacuum in a Thermos Flask?

A space with minimal air, reducing heat transfer by conduction and convection.

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Function of Thermos Flask

To keep liquids hot (or cold) for an extended time by minimizing heat transfer.

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How Thermos Minimizes Heat Loss?

By reducing conduction, convection, and radiation.

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What is a Thermos Flask?

A container designed to keep liquids hot or cold for extended periods.

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Thermos: Poor Conductor Part?

The screw stopper or lid.

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Thermos Flask: Plastic/Metal Use?

To reduce heat loss or gain by conduction.

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Thermos Flask: Silver Coating Use?

To reduce heat loss or gain by radiation.

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Metal Expansion

When heated, metals increase in size.

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Metal Contraction

When cooled, metals decrease in size.

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Drying Clothes

Heat from the sun dries wet cloth. Heat is moved through the air to dry it.

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Thermos Outer Container

The outer shell of the thermos.

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Thermos Stopper

The component that seals the thermos flask.

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Water Expansion/Contraction

Water rises when heated and falls when cooled.

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Experiment Aim: Air Expansion/Contraction

To observe how air increases in volume with heat and decreases when cooled.

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Experiment Aim: Water

To observe how water changes when heated or cooled.

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Colored Water Purpose

Colored water makes level changes easier to see.

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Heating Air

Air expands when heated.

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Cooling Air

Air contracts when cooled.

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Water Bath Purpose

Water is placed in a water bath to control the temperature change evenly.

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Expansion and Contraction of Materials

Materials that change in size when heated or cooled.

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Gas Expansion vs. Other States

Gases expand more noticeably than solids or liquids when heated.

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Gas Contraction vs. Other States

Gases contract more noticeably than solids or liquids when cooled.

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Balloon Experiment

The expansion and contraction of air can be observed using a balloon on a bottle placed in hot and cold water.

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Heating and Molecular Motion

Heat causes an increase in the volume of air molecules.

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Cooling and Molecular Motion

Cooling causes a decrease in the volume of air molecules

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Thermal Conductor

A material that allows heat to flow through it easily.

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Why Wax Melts?

Wax melts because heat increases its molecules' movement, weakening the bonds.

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Aim of Liquid Heating Experiment

To observe how heat moves through water.

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Heat Travels

The movement of heat from one place to another.

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Experiment 4 Title

Heat transfer through solid materials.

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Study Notes

  • Devices that simplify work are called simple machines.
  • A machine is any device used to simplify work.

Types of Machines

  • Simple and complex machines exist.
  • Simple machines include spades, hammers, seesaws, wheelbarrows, openers, scissors, pulleys, crowbars, beam balances, and spanners.
  • Complex machines consist of two or more simple machines.
  • Sewing machines and bicycles are examples of complex machines.

Types of Simple Machines

  • Six include levers, inclined planes, wedges, wheels and axles, pulleys, and screws.

Lever Defined

  • A lever turns or rotates around a fixed point, either a fulcrum or pivot.
  • Lever's main parts include fulcrum/pivot, effort, and load.
  • Crowbars, spades, claw hammers, wheelbarrows, bottle openers, scissor pairs, spanners, and shovels are examples of levers.

Lever Classes

  • Three lever classes exist.

First Class Lever

  • The fulcrum is positioned between the load and the effort.
  • Examples of first class levers are crowbars, scissors, beam balances and claw hammers.

Second Class Lever

  • The load is positioned between the effort and the fulcrum.
  • Wheelbarrows and bottle openers exemplify second class levers.
  • A wheelbarrow is a second class lever because the location of the load is in between the effort and the fulcrum.

Third Class Lever

  • The effort lies between the load and the fulcrum.
  • Tongs, brooms, fishing rods, tweezers, and shovels are third class levers.
  • An upright broom is considered a third class lever because the effort is between the fulcrum and the load during use.

Uses of Levers

  • Levers simplify work.
  • Wheelbarrows facilitate load carrying.
  • Claw hammers assist in nail removal.
  • Scissors are for hair or clothes cutting.

Inclined Plane Defined

  • An inclined plane is a wooden plank or iron bar tilted with one end higher than the other, creating a slope.
  • They are used to raise or lower objects from elevated places.
  • Ladders, ramps, sloping roads, hills, chisels, carpenter's planes, and ploughs exemplify inclined planes.
  • Inclined planes are used for loading/unloading cargo or cattle from trucks.

Wedge Defined

  • A wedge is a piece of wood or iron, thin on one end and thick on the other.
  • The iron part of an axe exemplifies wedges.
  • Wedges split timber/firewood.
  • A knife's sharpened edge and chisels are also wedges.
  • Wedges loosen stuck tools when chopping firewood or splitting logs.

Vocabulary Enhanced

  • Balloon: a small bag made of very thin rubber that expands when filled with air or gas
  • Contraction: the process of shrinking in size
  • Cork: a substance used as a bottle stopper
  • Expansion: an act of increasing or making something increase in size
  • Metal ball: a sphere made of metal
  • Metal ring: a metal object with a round shape like a bangle
  • Vacuum: a space that is completely empty
  • Beam balance: a simple machine in which the fulcrum is between the load and the effort
  • Lever: a simple machine that is divided into three major parts: the load, fulcrum and effort
  • Simple machine: basic machines which are levers, inclined planes, wedges, wheels and axles, pulleys and screws
  • Wedge: a piece of wood or iron that tapers to a thin edge

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Description

Explore simple machines: levers, inclined planes, and wedges. Learn about the three classes of levers and their applications. Discover how these machines simplify work using everyday examples like bottle openers and hammers.

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