Physical science

ninth grade physical science terms

Law

A description of a truth.

Phenomena

Anything observable or measurable.

Theory

A model that explains something, may or may not prove true.

Hypothesis

An educated guess of what could happen in an experiment.

Historical science

Not testable, unobservable, based off of a guess.

Operational

Able to be tested over and over and observed.

Ion

An atom or molecule with a different number of electrons and protons.

Atom

The smallest unit of matter.

Matter

Anything with mass that takes up space (plasma, liquid, gas, and solid).

Kinetic molecular theory

The belief that all types of matter are in constant motion.

Subatomic parts of an atom

Protons, neutrons, and electrons - atoms are neutral when the number of electrons equals the number of protons.

Liquid

Completely mobile properties, definite volume, shape determined by container, low compressibility, varies in viscosity, waves can go through the surface, fluid.

Solid

Particles are close together, fixed, definite volume/shape, dense, low compressibility.

Gases

Particles are far apart and move at high speeds, highly compressible, volume/shape determined by container, fluid.

Condensation

Gas to liquid - dew on grass.

Vaporization

Liquid into gas - boiling water.

Sublimation

Solid to gas - dry ice.

Deposition

Gas to solid - frost.

Physical change

Only alters the appearance, temporary/reusable, no energy change, mass unaltered.

Chemical change

Physical and molecular change, new substance, permanent and irreversible, mass is altered.

Accuracy

An assessment of measurement error, how far we are from the actual assessment.

Precision

An assessment of the exactness of a measurement, how close we are to the actual measurement.

Quantitative

Numerical measurements.

Qualitative

Descriptive measurements.

SI (System International)

A system that uses metric units.

Measuring limits

Factors that can affect the accuracy and precision of measurements.

Significant digits

Establishes the amount of precision of digits used in a measurement or calculation.

Scientific notation

A tool used to shorten longer numbers.

Density

The amount of mass of a substance (M = P x V).

Volume

Measuring the space enclosed in an object (V = L x W x H).

Scalar

A dimension that has a single piece of information.

Vector

A dimension that has two pieces of information - scalar and direction.

Motion

Change in position over time.

Mechanics

The modern study of motion.

Dynamics

What causes things to move.

Kinematics

How things move.

Speed

Distance over time it took to cover the distance - scalar.

DeltaT

End minus beginning.

Displacement

Distance between the start and end of an experiment, vector, positive or negative.

Distance

Total length traveled, always positive, scalar.

Velocity

Rate of completing a distance, vector.

Force

Push or pull on a system, vector represented by an arrow pointing any direction.

Friction

Contact force that works against the movement of systems moving past one another.

Kinetic friction

Friction between sliding objects.

Rolling friction

Friction between rolling and stationary objects.

Fluid friction

Drag of liquid on an object in the fluid.

Static friction

Friction between stationary objects.

Newton's first law

Whatever is in motion stays in motion and whatever is at rest stays at rest unless an outside force acts on it.

Newton's second law

Accelerated motion - F = M x A.

Newton's third law

For every action, there is an equal and opposite reaction.

Free fall

When objects fall due to gravity alone with no other forces acting on them.

Contact forces

Forces that cause systems to touch each other.

Compression

Things being pushed together (contact).

Tension

Things being pulled apart (contact).

Shear

Things distort or move parallel to each other (contact).

Torsion

Objects being twisted (contact).

Field forces

Forces that objects that don't touch, weaken with distance.

Gravitational

Affects everything, including light (field).

Magnetic

Affects iron, magnets, and moving charges (field).

Electric

Affects electrical charges (field).

Energy

Ability to do work, measured in joules.

Work

Force acting on an object through a distance, also measured

potential energy

Energy stored in a system

Kinetic energy

Energy of motion

Mechanical energy

Energy resulting from the motion of matter

Thermal energy

Energy of heat, all particles have motion and produces heat that flows through systems

Acoustic energy

energy of sound, particles occilate in a specific direction through matter

magnetic energy

a field force that attracts or repels magnetic objects

Radient energy

can be radiated by matter and transmitted through a vacuum, most common type is light

electrical energy

based on the charges of the particles in an atom. like charges repel, opposites attract

nuclear energy

given from the changing of the nucleus

Chemical energy

the energy stored between the bonds of atoms and molecules when bonded together

mass energy

theoretic energy that can turn energy to mass using E=m.c2

Elastic collisions

two objects collide and become deformed, heat given off and kinetic energy lost, not real on earth‒closest is two hockey pucks colliding

partially eleastic collision

two objects collide and get deformed, heat given and ke lost‒ baseballl hitting a baseball bat

ineleastic

two objects stock together after collision, both are deformed permanently‒icecream on pavement

1st law of thermodynamics (conseveration of energy law)

states that energy is not lost or gained, just transformed from one kind to another

power

Rate of doing work

mechanical advantage

measure of the reduction in effort to do a certain amount of work using a simple machine

distance princible

in order to gain mechanical advantage you need to sacrifice distance

Work

Force x displacement

ideal mechanical advantage (IMA)

ignorig the effects of friction on our simple machine

actual mechanical advantage (AMA)

calculating with the effects of friction

types of simple machines

pulleys, wheels and axels, inclinde planes..

Lever

ridgid bar resting on a pivot point

Power

Measured in watts

fluid mechaincs

study of how fluid flow and how forces and energy are transmitted through fluids

specific gravity (realative density)

measure of an objects density when compared to waters density, unitless

coanda effect

fluids flowing close to a curved surface follow the shap of the surface rather than a straight path

affects fluid pressure

depth of the liquid and how much pressure exerted by the fluid, density of the fluid, atmospheric gases gravity holds the gases more tightly the closer you get to the earths surface

bernoulli's principle

pressure in a stream of fluid is reduced as the speed of the flow is increased and vise versa

pascal's principle

changes pressure on the surface of a confined fluid are exertrd equally throughout the fluid at all points

archemidies princible

states that an immersed object is lifted by a force equal to weight of the displaced fluid

boyle's law

states that as volume decreases in a container pressure of the gas will increase and as the volume increase pressure decreases

charles's law

states that as temperature of a gas increases so does the pressure of the gas and as the temperature decreases so does the pressure

kinetic molecular theory

atoms, ions, molecules, and subatomic particlesa are always in motion

internal energy

sum of all kinetic energies and potetial energies between the particles

fiducial points

standard or measuring scale; must be fixed, percisley measurable and easliy reproduced

farenheit scale

fiducial points are between 32-212

celsius scale

fiducial points are between 0-100