75 terms

# Physical Science Mid-Year: Amir

#### Terms in this set (...)

Steps in the Scientific Method
-Gather information
-Form a hypothesis
Test hypothesis
Hypothesis
An educated guess
Theory
Hypothesis backed up by evidence
Experiment
Scientific method used to test hypothesis
Variable
Something that can be changed
Independent Variable
Variable that you can change
Dependent Variable
Variable that changes based on the Independent Variable
Control Group
People that fix/control the variable
Constant
Having two of the same things
Bias
Favoring one thing over another, not valid
Standard
Agreed upon unit of measurement
SI
International System, system of measurement used around the world
Volume
Amount of space an object takes up
Density
Amount of matter in an object
Mass
How much matter that makes up an object
Length
How long something is
Scientific Law
Something that is a fact about science
Model
A visual representing the experiment that is smaller
Acceleration
Change in speed and direction
Positive Acceleration
Increasing velocity
Negative Acceleration
Decreasing velocity
Gravity
Attractive force between any two bodies
Rate
Rate of change, quantity of change
Acceleration due to gravity
9.8 m/s 2
3 ways of accelerating
Speeding up, slowing down, or changing direction
Distance
How far something goes
Displacement
How far something goes and what direction it came from the starting point
Instantaneous Speed
How fast you are going at any moment in time
Average Speed
Speed over the full time of travel
Velocity
Has speed and direction, it is a vector quantity
Force
A push or pull
Newton's First Law 'Law of Inertia'
If an object is in motion, it stays in motion. If an object is at rest, it stays in rest.
Inertia
Tendency of an object to move or to stay still
Weight
The force of gravity
Balanced Forces
Equal forces acting on each other
Static equilibrium
Something that is not changing
Unbalanced Forces
Unbalanced forces acting in opposite directions
Newton's Second Law 'Force Law'
An object moves in the direction of an unbalanced force
Static Friction
When two objects are in contact with each other but they are not moving
Sliding Friction
when an object slides on the surface
Rolling Friction
When an object rolls on the surface
Terminal Velocity
When you stop accelerating and the forces are balanced by air resistance
Air Resistance
An opposing force of motion caused by air
Newton's Third Law 'Action Reaction'
Whenever a force applies a force, another force applies a force to it
Projectile Motion
When you throw something, it goes in a rainbow/arch motion.
Centripetal Force
Anything that is moving in a circular motion
Momentum
Mass x Volume
Conservation of Momentum
Momentum cannot be lost or gained but it could be transferred
Joule
SI unit for energy
Energy
Ability to cause change
Calorie
1 Calorie= 4184 joules
Potential Energy
Stored energy
Kinetic Energy
Energy of motion
Elastic Potential Energy
Energy stored in things that stretch
Chemical Potential Energy
Energy stored in chemical bonds between atoms
Gravitational Potential Energy
Energy stored in things that are moving
Mechanical Energy
Kinetic Energy + Potential Energy
Law of Conservation of Energy
Energy may change from one form to another but the total amount of energy never changes
Nuclear Fusion
Two nuclei are fused together. Takes place in the sun
Nuclear Fission
Two nuclei are broken apart
How to do work
-an object has to move
-the direction of movement must be in the direction of the applied force
Power
Work divided by time
Inclined Plane
Sloping surface used to raise objects
Wedge
An inclined plane with one or two sloping slides
Screw
Inclined plane wrapped in a spiral around a cylindrical post
Lever
Bar that is free to pivot about a fixed point
Pulley
Grooved wheel with a rope running along the groove
Wheel and axle
Two wheels of different sizes that rotate together
Compound Machine
A machine with two or more items that make work easier
Resistance Force
The force in which the effort force must overcome to do work
Effort Force
A force that moves an object over a distance by overcoming the resistance force
Efficiency
The amount of energy used for work