Unit 3: Forces, Fluids & Density Flashcards
Particle Theory of Matter
- Theory that explains the behaviour of solids, liquids, and gases.
- It states that all matter is made up of tiny moving particles that attract each other and have spaces between them.
- Adding heat makes particles move faster decreasing density resulting in a state of matter change.
Solid
Particles are close together and in a fixed place; denser than liquids.
Liquid
Particles are close together but can slide around and over each other; denser than gases.
Gas
Particles are far apart and move rapidly.
Fluid
Any matter that has no fixed shape, can flow, and takes the shape of its container; any substance in a gas or liquid state
Viscosity
A liquid’s internal resistance or friction that keeps it from flowing
Weight
Measure of the force of gravity on an object; measured in newtons (N)
Mass
Measurement of the amount of matter that is in an object; often measured in grams
Density
Mass per unit of volume; measure by dividing the mass of a substance by its volume; the amount of matter or number of particles in a given volume; g/mL or g/cm3
D = M/V
Volume
The amount of space taken up by an object; liquids measured by mL and solids measured by cm3
Force
Push or pull that tends to cause an object to move or change its motion; measured in Newtons (N)
Buoyant Force
Upward force that a liquid exerts on an object, opposite to the pull of gravity on an object in a liquid; an important property of fluids; the property that causes a ship to float in water
Gravitational Force
Force trying to pull an object down to the center of the Earth = 9.8m/s2 on Earth
Pressure
A measure of the amount force applied to a particular area; measure in pascals (Pa) = N/m2
Compression
Results when a force pushes on an object
Hydraulic Device
Devices that use water or some other liquid in motion under pressure to do useful work
Hydraulic Fluid
The liquid part put into a hydraulic system
Hydraulic System
System that uses liquids in a confined space to transfer forces; operates according to Pascal’s Law
Pneumatic Devices
Devices that use air or other gases in a confined space or transmit forces
Pneumatic Systems
Confined, pressurized systems that use air or other gases to transmit forces
Variables
Things that can be changed in a scientific experiment
Fair Test
Experiment in which only one variable is changed at a time
Balanced Forces
Opposite and equal forces acting on an object; for an object to remain suspended in water, the downward force of gravity must be balanced by and equal upward force
Newton (N)
The unit used in science for measuring gravitational force, weight, and pressure.
Personal Flotation Device (PFD)
A safety device designed to keep a person afloat in water
Archimedes’ Principle
Buoyant force acting on an object equals the weight, or gravitational force, of the fluid displaced by the object
Swim Bladder
A specialized organ in many fish, containing a mixture of air and water; this organ allows the fish to control it’s swimming depth
Ballast Tank
Tanks in submarines that enable the submarine to dive and resurface; ballast tanks depend on a feature similar to a swim bladder in fish
Water Displacement Method
Method of measuring volume which involves placing an object in a container of water and measuring the amount of water moved (displaced); alternatively, placing an object into a container full of water and measuring the volume of the overflow