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Questions and Answers
Explain why a spark from a firework will not hurt you as much as a cup of hot tea?
Explain why a spark from a firework will not hurt you as much as a cup of hot tea?
A spark from a firework does not contain much heat energy even though it may be very hot. A cup of tea, even though it may not be very hot, can still burn your tongue because it contains a lot of heat energy.
What is heat? What are units of heat energy called?
What is heat? What are units of heat energy called?
Heat is the transfer of energy from a higher temperature object to a lower temperature object. Units of heat energy are called joules (J) or kilojoules (kJ).
What is temperature? How is temperature measured?
What is temperature? How is temperature measured?
Temperature is a measure of how hot or cold something is, measured in degrees Celsius (°C) with a thermometer.
Describe how the movement of its particles changes as the temperature of a substance changes.
Describe how the movement of its particles changes as the temperature of a substance changes.
What is absolute zero?
What is absolute zero?
What is the Kelvin scale?
What is the Kelvin scale?
What happens to the movement of particles in a liquid when it is heated?
What happens to the movement of particles in a liquid when it is heated?
What name is given to the change of state from:
What name is given to the change of state from:
Where does the heat energy come from to melt an ice cube which is left on a kitchen work surface?
Where does the heat energy come from to melt an ice cube which is left on a kitchen work surface?
Which materials make the best conductors of heat?
Which materials make the best conductors of heat?
What is an insulator? Name three insulators.
What is an insulator? Name three insulators.
Explain how heat is conducted along a metal bar.
Explain how heat is conducted along a metal bar.
Suggest why the base of a saucepan is made of metal?
Suggest why the base of a saucepan is made of metal?
Suggest why the handle of a saucepan is made of plastic?
Suggest why the handle of a saucepan is made of plastic?
Suggest why polar bears have a thick coat of fur.
Suggest why polar bears have a thick coat of fur.
Suggest why birds fluff out their feathers in winter.
Suggest why birds fluff out their feathers in winter.
Why can liquids and gases carry heat?
Why can liquids and gases carry heat?
Explain how a heater warms all the air in a room?
Explain how a heater warms all the air in a room?
Why do you think it takes a long time to heat a room with a high ceiling?
Why do you think it takes a long time to heat a room with a high ceiling?
Why do you think convection cannot happen in solids?
Why do you think convection cannot happen in solids?
When we cook food under a grill, heat must travel downwards from the heating element in the grill to the food. This heat cannot be carried by convection because convection carries hot air upwards. The heat cannot be conducted to the food because air is a bad conductor of heat. So, there must be another way of moving heat to the food - this is by radiation. The heat travels as tiny electromagnetic waves called infrared waves. The hotter an object is, the more infrared radiation it emits. No particles are involved, unlike in the processes of conduction and convection, so radiation can even work through the vacuum of space. This is why we can still feel the heat of the Sun, although it is 150 million km away from the Earth.
When we cook food under a grill, heat must travel downwards from the heating element in the grill to the food. This heat cannot be carried by convection because convection carries hot air upwards. The heat cannot be conducted to the food because air is a bad conductor of heat. So, there must be another way of moving heat to the food - this is by radiation. The heat travels as tiny electromagnetic waves called infrared waves. The hotter an object is, the more infrared radiation it emits. No particles are involved, unlike in the processes of conduction and convection, so radiation can even work through the vacuum of space. This is why we can still feel the heat of the Sun, although it is 150 million km away from the Earth.
Some surfaces are better at emitting (giving off) thermal radiation than others. Good emitters of radiation are also good absorbers. White or silvery surfaces are poor absorbers because they reflect most of the radiation. That is why in hot, sunny countries houses are often painted white to keep them cool inside.
Some surfaces are better at emitting (giving off) thermal radiation than others. Good emitters of radiation are also good absorbers. White or silvery surfaces are poor absorbers because they reflect most of the radiation. That is why in hot, sunny countries houses are often painted white to keep them cool inside.
Why is a dark surface a better emitter of thermal radiation than a shiny surface?
Why is a dark surface a better emitter of thermal radiation than a shiny surface?
Why are houses in hot countries often painted white to keep them cool inside?
Why are houses in hot countries often painted white to keep them cool inside?
Why is the inside of a white car cooler than the inside of a black car on a hot summer's day?
Why is the inside of a white car cooler than the inside of a black car on a hot summer's day?
Why does aluminum foil help keep food warm?
Why does aluminum foil help keep food warm?
Why do central heating radiators work better if they are painted black?
Why do central heating radiators work better if they are painted black?
Why is a vacuum flask commonly called a Thermos flask?
Why is a vacuum flask commonly called a Thermos flask?
Explain why a vacuum flask can keep drinks cold as well as hot.
Explain why a vacuum flask can keep drinks cold as well as hot.
What is the function of the silver lining in a vacuum flask?
What is the function of the silver lining in a vacuum flask?
Describe what is happening:
Describe what is happening:
What is needed to make this happen?
What is needed to make this happen?
Suggest where this energy might come from?
Suggest where this energy might come from?
Give an example of where evaporation takes place in the home.
Give an example of where evaporation takes place in the home.
Why does a spark from a firework not hurt very much if it lands on your hand?
Why does a spark from a firework not hurt very much if it lands on your hand?
Heat energy is measured in...
Heat energy is measured in...
Which of these does the kinetic theory NOT explain?
Which of these does the kinetic theory NOT explain?
What happens when one end of a metal bar is heated?
What happens when one end of a metal bar is heated?
What is the name of the continuous circulating stream of water set up inside a kettle when it is heated?
What is the name of the continuous circulating stream of water set up inside a kettle when it is heated?
You can still burn your tongue on a cup of tea even though it may not be very hot.
You can still burn your tongue on a cup of tea even though it may not be very hot.
Heat is measured with a thermometer.
Heat is measured with a thermometer.
When water changes state from ice to a liquid, the total mass of the water never changes.
When water changes state from ice to a liquid, the total mass of the water never changes.
A short metal spoon is better for stirring hot soup than a long metal spoon.
A short metal spoon is better for stirring hot soup than a long metal spoon.
Describe what happens to particles in a solid when it melts.
Describe what happens to particles in a solid when it melts.
Describe what happens to particles in a liquid when it evaporates.
Describe what happens to particles in a liquid when it evaporates.
What happens to ice at 0°C?
What happens to ice at 0°C?
What happens to water at 100°C?
What happens to water at 100°C?
Explain why the temperature of boiling water does not change, no matter how much it is heated.
Explain why the temperature of boiling water does not change, no matter how much it is heated.
Ice is a ______. When it is heated, it ______ and becomes water. Water is a ______ which boils at 100°C. At this temperature, it turns into a ______ called steam. When steam cools it ______ and turns back into water. At 0°C water ______ and turns back into ice. These are examples of changes of ______.
Ice is a ______. When it is heated, it ______ and becomes water. Water is a ______ which boils at 100°C. At this temperature, it turns into a ______ called steam. When steam cools it ______ and turns back into water. At 0°C water ______ and turns back into ice. These are examples of changes of ______.
Suggest why
a) the base of a saucepan is made of metal.
b) the handle of a saucepan is made of plastic.
c) polar bears have a thick coat of fur.
d) birds fluff out their feathers in winter.
Suggest why a) the base of a saucepan is made of metal. b) the handle of a saucepan is made of plastic. c) polar bears have a thick coat of fur. d) birds fluff out their feathers in winter.
Why in hot countries, houses are often painted white?
Why in hot countries, houses are often painted white?
On a hot summer's day, the inside of a white car is cooler than the inside of a black car. Why?
On a hot summer's day, the inside of a white car is cooler than the inside of a black car. Why?
Aluminium foil helps keep food warm. Why?
Aluminium foil helps keep food warm. Why?
Central heating radiators work better if they are painted black. Why?
Central heating radiators work better if they are painted black. Why?
Describe what is happening in the kinetic theory model of an evaporating liquid.
Describe what is happening in the kinetic theory model of an evaporating liquid.
What happens to particles in a solid when it melts?
What happens to particles in a solid when it melts?
What happens to a liquid when it evaporates?
What happens to a liquid when it evaporates?
Flashcards
Chapter 1
Chapter 1
The first part of a book or document.
Touch
Touch
The sense of feeling.
Object
Object
A physical thing.
Heat
Heat
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Tongue
Tongue
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Study Notes
Heating and Cooling
- Heat is the amount of energy in an object.
- Temperature measures how hot or cold something is. Measured in degrees Celsius (°C).
- Heat energy transfers from hotter to colder objects.
- Particles in matter are constantly moving.
- Higher temperature = faster particle movement
- Absolute zero is the temperature at which particles stop moving, -273°C.
- Kelvin scale starts at absolute zero and has degrees the same size as degrees on the Celsius scale.
- Solids have particles vibrating in place, liquids have particles able to move around, gases have particles free to move in any direction.
- Changes in state (melting, evaporation, condensation, freezing): heat changes particle movement and arrangement.
Transfer of Heat
- Conduction: Heat travels through solids (e.g., stirring hot soup with a metal spoon). Metals are good conductors, non-metals (e.g., glass, plastic) are poor conductors (insulators). Air is a good insulator.
- Convection: Heat travels through liquids and gases. Hot material rises, cool material sinks, creating a circulating current (e.g., heating a room with a heater).
- Radiation: Heat travels as waves (e.g., cooking food under a grill). Dark surfaces absorb radiation better, shiny surfaces reflect it better.
Comparing Emitters and Absorbers
- Dark surfaces are better emitters and absorbers of heat.
- Shiny surfaces are poor emitters and absorbers of heat.
Vacuum Flask (Thermos Flask)
- Vacuum flask design minimizes heat transfer to preserve temperature (hot or cold).
- Features include a vacuum between walls, silver lining, and a stopper. These reduce heat loss through conduction, convection, and radiation.
Changes of State
- Melting: solid changes to liquid.
- Evaporation: liquid changes to gas.
- Condensation: gas changes to liquid.
- Freezing: liquid changes to solid.
- Mass is conserved during changes in state (matter is neither created nor destroyed).
Kinetic Theory
- The kinetic theory describes the behavior of particles in different states of matter.
- The theory is important in understanding how temperatures and heat cause matter to change
Investigation - Heating Ice Example
- The graph shows how temperature changes with the addition of heat to ice, demonstrating the energy needed to convert between phases.
- Different stages of heating ice show that the temperature remains constant as it melts (or boils) because the supplied energy goes into changing state rather than increasing the temperature.
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Description
Explore the fundamental concepts of heating and cooling in this quiz. Understand how heat energy transfers between objects and the behavior of particles in different states of matter. Test your knowledge on conduction, convection, and temperature scales.
