88 terms

# Physical Science Semester 1

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

Science
A method for studying the natural world using investigation; a body of knowledge.
Scientific Theory
An explanation of things or events based on knowledge from investigations. It's a guess, but it can be changed.
Scientific Law
A statement about what happens in nature and seems to be true all the time.
Scientific Method
Using logic to solve a problem.
Steps to Scientific Method
Question, hypothesis, material, procedure, observation, conclusion.
Observation
Using your 5 senses to perceive objects or events.
Hypothesis
An educated and testable statement that can never be proven beyond doubt because you can always learn new information.
Controlled Experiment
Based on a comparison of a control group and experimental group.
Control Group
The group that receives no treatment and is compared to every other group.
Experimental Group
The group that is being tested.
Independent Variable
The thing in an experiment that changes or is being tested.
Dependent Variable
The result of what's being changed.
Constant
The thing in an experiment that remains the same when everything else changes.
Conclusion
Determining whether or not your hypothesis was supported based on an analysis of your data.
Mass
The amount of matter that makes up an object, or how big the object is.
Frame of Reference
A system that measures the position of an object by comparing it to objects in motion.
Motion
The change of an object's position relative to the frame of reference.
Distance
How far an object travels from a starting point.
Displacement
The distance and direction of an object's change in position compared to a starting point.
Vector
An arrow that shows magnitude and direction.
Scalar Measurement
Anything that measures only magnitude. (speed & distance)
Vector Measurement
Any measurement that requires both magnitude and direction. (Velocity, acceleration, displacement, momentum)
Speed
How fast something is moving or the rate at which an object changes position.
Velocity
The speed and direction of a moving object.
Acceleration
The rate of change in velocity.
Force
Any push or pull.
Balanced Force
Occurs when the forces being applied to an object are equal in size but opposite in direction.
Unbalanced Force
Occurs when the forces being applied to an object are not equal and results in the movement of an object.
Net Force
The sum of all forces acting on an object.
Centripetal Force
The force exerted toward the center of a curved path.
Friction
The force that opposes the motion of 2 touching surfaces.
Gravity
The attractive force between 2 objects.
Terminal Velocity
The maximum speed that a falling object will reach.
Newton's 1st Law
An object in motion stays in motion unless an unbalanced force acts on it.
Newton's 2nd Law
Explains the relationship between force, mass, and acceleration. (F=ma)
Newton's 3rd Law
For every action there is an opposite and equal reaction.
Weight
The gravitational force exerted on an object. (How heavy an object is)
Inertia
The tendency of an object to resist a change in motion.
Momentum
Something that is found in all moving objects and makes an object harder to stop.
Fluid
Any liquid or gas.
Air Resistance
A friction-like force that opposes the motion of objects that are moving through the air.
Projectile
Anything that is shot or thrown into the air.
Energy
The ability to cause change or do work.
Kinetic Energy
Energy found in anything that is moving.
Potential Energy
Stored energy due to interactions between objects.
Mechanical Energy
All of the kinetic and potential energy within a system.
Law of Conservation of Energy
States that energy is not created or destroyed, it only changes forms.
Power
The rate at which work is being done.
Work
A force acting through a distance. Caused when an object moves in the direction of the applied force.
Machine
Any device that makes work easier by changing a force.
The number of times a machine multiplies the input force. The more you have, the less effort you need.
Efficiency
The ratio of output work to input work.
Fulcrum
The fixed point that a lever pivots on.
Elastic Potential Energy
Energy stored in objects that stretch or compress.
Chemical Potential Energy
Energy stored in chemical bonds.
Gravitational Potential Energy
Energy stored due to an object's position.
Thermal Energy
The sum of all kinetic and potential energy of the particles that make up an object.
Heat
Thermal energy that is transferred from hot to cold objects.
Temperature
A measure of the average kinetic energy of the particles that make up an object.
Conduction
A transfer of energy due to direct contact.
Convection
A transfer of energy within fluids by the rising and falling of particles.
A transfer of heat by electromagnetic waves through empty space.
Law of Conservation of Momentum
The total momentum of a group of objects remains the same unless an outside force acts on the object. One object can lose momentum, but the other object gains it.
Law of Conservation of Energy
Energy is not created or destroyed, it only changes forms.
Inclined Plane
A simple machine that is a sloping surface that connects high and low elevation.
Wedge
A simple machine that consists of 2 inclined planes that move and do work.
Screw
A simple machine that consists of an inclined plane wrapped around a central bar or cylinder to form a spiral.
Lever
A simple machine that consists of a rigid bar that is free to pivot around a fixed point.
Wheel and Axle
A simple machine that is made up of 2 different sized circular objects that are connected and turn in the same direction.
Pulley
A simple machine that is a rope, belt, or chain wrapped around a grooved wheel.
Mass and Distance
2 things that influence the amount of gravity of an object.
Static Friction
Prevents 2 objects from moving past each other.
Sliding Friction
Opposes motion of 2 objects sliding past each other.
Rolling Friction
Resists motion when an object rolls on a surface.
Power
Represented in watts.
Force
Represented in Newtons.
Work/Energy
Represented in Joules.
Speed
Represented in m/s.
Acceleration
Represented in m/s^2.
Weight
Represented in kilograms.
Distance
Represented in meters
Horsepower
Represented in Horsepower.
Newton
Represented in kgm/s^2.
Types of surfaces in contact & amount of force.
2 things that influence friction.
Metric Conversions
Kilo, Hecta, Deka, Base, Deci, Centi, Milli.
Speeding up, slowing down, changing direction
3 things that cause an object to accelerate.
9.8 m/s^2
Acceleration due to gravity.
Increase force, increase distance, change direction of force
3 ways a simple machine can make work easier.