Studied by 9 people
bro this took so long
Fluid
Any substance that flows
Slurry
A mixture of water and solids
Matter
Anything that has mass and volume
Mass
A measure of how much matter there is in a substance
Volume
A measure of how much space a substance takes up
Particle Theory of Matter
All matter is made up of tiny particles.
All particles are in constant motion.
All particles of one substance are identical.
Temperature affects the speed at which particles move.
In liquids and solids, the particles are close together and have strong forces of attraction between them.
In a gas, there are spaces between the particles.
Thermal Expansion
An increase in the volume of a substance in response to an increase in its temperature
Viscosity
The resistance of a fluid to flow
Friction
A force that works to slow down motion as a result of surfaces rubbing against each other
Flow Rate
A measure of the speed at which a fluid flows from one point to another
Density
The amount of mass contained in a given volume. It describes how closely packed together the particles are in a substance
Density Rules
• If the density of a substance is greater than the density of the fluid, the substance will sink
• If the density of a substance is less than the density of the fluid, the substance will float.
• If the density of a substance is the very same as the density of a fluid, the substance will "hover" in place.
Density and Temperature
A substance can have different densities based on its temperature. For example, warm water floats on cold water.
Calculating Density
Density = Mass / Volume
Force
A push or a pull that acts on an object
Buoyancy
The tendency of an object in a fluid to rise or sink due to density differences with its surroundings
Buoyant Force
The upward force exerted by a fluid
Buoyancy and Gravity
An object will rise in a fluid when:
the density of the object is less than the density of the fluid
the buoyant force on the object is greater than the force of gravity on the object
An object will sink in a fluid when:
the density of the object is greater than the density of the fluid
the buoyant force on the object is less than the force of gravity on the object.
An object will float in a fluid when:
the density of the object is equal to the density of the fluid
the buoyant force on the object is equal to the force of gravity on the object
Archimedes’ Principle
The buoyant force on an object is equal to the weight of the fluid displaced by the object.
Plimsoll Line
Shows how heavily a ship can be safely loaded in different water conditions
Pressure
The amount of force applied to a given area
Changes in Pressure
Air pressure changes with altitude. The higher you go, the more air pressure you will experience. You may feel a pop sound when you change altitude quickly, because the air pressure in your ear has to adjust.
Pressure and Fluid Flow
If a fluid is allowed to move, it will always go from an area of higher pressure to an area of lower pressure.
Pressure and Temperature
When the temperature of a fluid is increased inside a container, the pressure increases. This only happens when the fluid is at a constant volume.
Compression
A decrease in volume caused by a force
Compressibility
The property of being able to be compressed
Incompressible
Something that can not be compressed
Fluid System
A group of parts, including at least one fluid, that interact with each other and function together as a whole. Examples: Circulatory system, respiratory system, and movement of sea stars.
Pascal’s Law
When force is applied to an enclosed fluid, the increase in pressure is transmitted equally to all parts of the fluid
Keeping in the Pressure
If you cut a hole on the side of a bottle and pushed down on the cork, the increased pressure would force the water out through the hole. For a fluid system to function properly, the entire system must be completely sealed.
Hydraulic Systems
Systems that use a liquid under pressure to transmit a force and do work
Liquids Cannot be Compressed
Since fluids cannot be compressed, when pressure is applied to a liquid in a pipe or tube in a hydraulic system, the force can be transmitted for a distance
Example: Hose connected to a water tap
Multiplying the Force
Hydraulic systems can multiply the force exerted by a liquid.
Hoist
Uses two pistons of different sizes to create pressure to lift a vehicle
Piston
A disk that moves inside a cylinder
Pneumatic System
A system that usees gas under pressure to transmit a force. For a gas to work in these systems, it must first be compressed.
Air Under Pressure
When a diver ascends to quickly, the sudden change in pressure causes the nitrogen gas in their air tanks to bubble out of the blood and tissues. One treatment for this is to put the body in a hyperbaric chamber, which increases the pressure surrounding the diver’s body. The increased pressure causes the gas bubbles to redissolve into the blood and tissues.
Pump
A device that moves a fluid through or into something, like the heart
Bicycle Pump
A pump that has a piston which moves up and down in a cylinder. When the piston is pulled up, air fills the cylinder. When it is pushed down, a force is applied to the air in the cylinder, therefore compressing it and increasing its pressure.
The Archimedes Screw Pump
Some pumps raise water from a lower elevation to a higher elevation, while other pumps can force air into tires or oil through a car’s engine. There are many different types of pumps, but they all work in a similar way, by creating areas of high and low pressure.
Valvs
Devices that control the flow of fluids
Oil Spills on Water
Oil is the most common pollutant of water, which over 3 million tonnes of oil polluting Earth’s water systems annually. When oil is added to water, it floats on top, as it is less dense than water. This property makes it much easier to clean up oil, as it is easier to pick it up from the surface than at the bottom. However, on large bodies of water, waves can cause the oil to mix temporarily with the water.
The Impact on the Environment
The damage caused by oil spills depends on many factors, like oil type, location, and the size of the spill.
Oil coats the plants living on nearby shorelines
This blocks the sunlight and prevents gas exchange, causing the plants to die
Oil breaks into smaller particles and is ingested by zooplankton and small fish
The ingested oil becomes part of the marine food chain
Oil coats the feathers and fur of birds and mammals
The oil reduces the insulating ability of the feathers or fur. The animals die of hypothermia.
The animal is much less buoyant in the water.
Oiled feathers make it difficult for birds to fly, find food, or avoid predators.
When the animals try to clean themselves they ingest the oil, which causes kidney damage and digestion problems.
Clean-up Methods
Booms: Large, floating barriers that act like a fence to contain the oil
Skimmers: Machines like vacuum cleaners that pull up the oil from the surface of the water. The water must be calm in order for skimmers to be effective.
Sorbents: Large, spongey materials that absorb the oil. When a sorbet gets too soaked in oil, it becomes denser than the water and sinks.
Dispersants: Chemicals like detergents which break the layer of oil into smaller pieces, but the oil remains in the water, so it may continue to be harmful to marine life.
Burning: This can remove over 90% of the spill, if it is more than 3mm thick and has happened recently. This is ineffective if the winds are strong.
Bioremediation: Uses bacteria and fungi to break down oil. Nitrates or fertilizers are added to the spill to provide nutrients for quicker growth of the bacteria and fungi.
Oil Spills on Land
Most marine oil pollution comes from oil spills that occurred on land. The environmental impact of a spill on land is much easier to clean up since it doesn’t spread as quickly. Barriers are placed around the spill to contain the oil, sorbents are used to soak up the oil, and the top layers of contaminated soil are excavated and removed.
Oil is not the Only Problem
If you see an oil slick floating on the surface, that water is contaminated. Many fluids don’t provide visible clues when they are spilled into water, like perchloroethylene (a dry-cleaning fluid) which when spilled into water sinks to the bottom. Materials like these are much harder to clean up than those that float. We must be aware of what we dump on land, because fluid spills have both an economic and environmental impact. The average cost of cleaning up a fluid spill is between $20-$200 per litre spilled. Accidental spills and natural sources account for nearly 30 percent of the pollution entering our water. Over half of the pollution is a result of our day-to-day use of fluids.
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