Understanding viscosity and fluids

• All fluids exhibit viscosity, which is the internal friction that resists flow.

Investigating Viscosity

• The Particle Theory of Matter explains matter by describing it as a model, explaining the different states, and explaining what happens when matter changes states.
• Solids have particles close together in a fixed arrangement.
• Liquids have particles close together but able to slide around.
• Gases have particles far apart and moving rapidly.
• The Particle Theory can describe fluids and their behaviours.
• Fluids are any matter that has no fixed shape and take the shape of their container.
• It is important to consider safety when working with fluids as some are unsafe.
• Hazardous Household Product Symbols (HHPS) indicate the level and type of danger, using triangles for "caution" and octagons for "danger."
• Workplace Hazardous Materials Information System (WHMIS) safety symbols are seen in all Canadian workplaces and are important to understand for handling dangerous materials safely.
• Viscosity is a liquid’s internal resistance or friction that keeps it from flowing.
• The greater the friction between particles in a fluid, the higher the viscosity.
• Fluids with high viscosity do not flow as easily as those with low viscosity.
• Viscosity can be determined using a bubble test (timing how long an air bubble takes to rise) or a ramp method (timing how long a fluid takes to flow down a ramp).
• The longer it takes for a bubble to travel or a fluid to flow down a ramp, the higher its viscosity.
• Intermolecular forces and particle shape affect a fluid's viscosity.
• Stronger attractions between particles lead to higher viscosity.
• Small particles and certain shapes allow particles to move past each other easily, resulting in lower viscosity.

The Effect of Temperature on Viscosity

• Temperature can significantly affect fluid viscosity.
• As temperature increases, viscosity decreases because particles move with more energy.
• As temperature decreases, viscosity increases because particles move with less energy.
• Motor oils are assigned a viscosity number by the Society of Automotive Engineers (SAE).
• In colder weather, use oils with lower viscosity and in warmer weather, use oils with higher viscosity.
• Viscosity modifiers in motor oil change the oil's characteristics and improve fuel economy and performance.
• All matter is made of tiny particles that are constantly vibrating.
• Adding heat makes particles move faster and vibrate more.

Density

• Not only do different fluids have different viscosities but also different densities.
• Density is the amount of matter or number of particles in a given volume.

Weight, Mass, and Volume

• Weight is the measure of the force of gravity on an object.
• Mass is the quantity of matter in an object
• Volume is the amount of space an object occupies.
• Mass is measured in grams (g), with the base unit being the kilogram (kg).
• Water has a density of exactly 1 g per mL.
• The density of a substance is the ratio of its mass to its volume (D=m/V).
• The units for the density of liquids and gases are usually given in g/mL or g/cm³.
• Density is the mass per unit of volume.
• A graph of mass vs. volume shows that a substance with a higher density has a steeper slope.
• Density observations are taken at the same temperature.

Experimenting with Density

• It is still possible to determine the density of a substance, even if the amount of matter changes.
• Viscosity can be influenced by volume.
• Archimedes discovered the concept of density.
• The volume of water displaced by an object equals the volume of the object.
• Density is another important property of fluids.
• One can estimate volume by displacement, using a measuring cup and enough water to cover the fat being measured.

Density and the Particle Theory of Matter

• Temperature affects the density of a fluid.
• The Particle Theory of Matter can help us understand that if a given sample of a substance stays at a constant temperature, the energy of particles stays the same.
• When energy is added to a substance and according to the particle theory, the particles begin to vibrate and when you observe a solid change to a liquid, and eventually to a gas, the particles vibrate and move more rapidly increasing both pressure and volume while decreasing density.
• When the particles move more rapidly, the increase can cause two things to happen. First, the volume increases because the particles need more room to move. The number of particles does not change, meaning that the density decreases.
• Water is an exception from the increase because unless the water is colder than 4 degrees celsius, warm water has a lower density than cold water.

Floating and Density

• Explaination of healing waters in mineral rich lakes and the legend of manitou beach
• Plimsoll Line explanation of cargo ships line and tropical vs fresh water.

What Floats on What?

• Less dense liquids and solids floated on denser liquids.

Buoyant Force and Gravitational Force

• Buoyant, then, is the force that acts against gravity. The force trying to pull an object down in a fluid is gravity.

The Bathyscaph

• The bathycaph, created for exploration to great depths is a model for understanding balanced and unbalanced forces.

Personal Flotation Devices

• Life jackets are bulky but can keep an unconscious person floating on his or her back. Personal flotation devices are more comfortable, but they are only designed to keep a person afloat. And it is important to know if it is right for you!
• A PFD is designed to keep you afloat in water, and is less bulky than a life jacket. Both life jackets and PFDs must be the right size to be effective. If either one is too small, there is not enough upward force exerted to keep a swimmer afloat.

Floating and Destiny

• An explanation that water at a certian level of density and salinity can help an object float

Rules of Buoyancy

• Determine if an object will sink, rise, or stay at the same position in the fluid. depending on if the gravitational force is equal to or less than the bouyant force.

Buoyancy

• Keyconcepts: Forces Buoyant force First nations designs Conoe and kayak technology
• The buoyant force is exerted by a liquid, pushing an object up against the force of gravity. The buoyant force is affected by the type of liquid, and can be calculated by subtracting the weight of the object in the liquid from the weight of the object in air.
• Living and non-living things are able to control their depth in water by altering their weight.
• From observations over many generations, First Nations, Inuit, and Métis boat designers built up place-based knowledge that enabled them to create a variety of boat designs to suit different purposes.
• Modern canoe and kayak technologies depend on designs unchanged from those of traditional craft.

Boat Building

• Steel is much denser than water, yet steel boats are able to float.
• Types of boats have been used by people for thousands of years and have developed over centures of everyday use.
• Canoe buildng process

Boat design

• What builders need to consider and evaluate when building a boat

More on canoe and kayak design

• What are the different canoe and kayak designs and what purpose do they serve.

Floating and Density

• A re-telling of a legend manitou beach, and the plimsoll line and how to tell if a boat is too full

Forces fluids and Density

• Unit 3 forces fluids and density

Unit 3 continued

• Discussion on buoyancy and forces

Air-Bag Systems As Protection

• How does the Particle Theory explain the fact that gases are compressible and liquids are not? Pneumatic systems use air.
• Moisture in the air can freeze. Air does not become viscous in cold temperatures.
• Air does not need long warm up times in cold temperatures. Air is not flammable Pneumatics exhaust air into the environment
• Most cannot work under water. They tend to require cleaning maintenance. They may give off potentially harmful exhaust

How does Pressure work?

• Unit Summary key concepts are particle theory, fluid, and viscosity
• Summary - The Particle Theory explains differences among states of matter, why fluids flow, and how temperature affects different materials
• A fluid is a gas or liquid that flows and takes on the shape of its container
• The viscosity of a fluid is measured by how fast the fluid flows. Viscosity increases as temperature decreases

Further Pressure and Fluids

• Unit summary of wieght and mass ,volume and density
• Weight is the measure of the force of gravity on an object, while mass is the amount of matter in the object. The unit for weight is the newton and the unit for mass is the kilogram.
• The volume of an object is how much space it takes up, and can either be measured directly using measuring tools, or measured by displacement of water. - A Fluid Is A gas or liquid thst flows sbd takes On THE shspe of is contsiner
• Water's density at 4°C is defined as 1 g/mL. Water is a special fluid and acts as the universal solvent. Water is the only pure substance that is more dense in liquid form than it is in solid form.