Physical Science Test 3 Terms

Density

measure of the compactness of matter

Liquid Pressure

not effected by shape, width, or length

weight

Mass is not _____

Buoyancy

upward force exerted by a fluid and opposing weight; (object feels like it weighs less in fluid, less by the weight of displaced fluid)

Displacement Rule

completely submerged object always displaces a volume of liquid equal to its own volume

Archimedes’ Rule

immersed body is buoyed up by a force equal to the weight of the fluid it displaces; object will be pushed by a force equal to its own weight

Principle of Flotation

a floating object displaces a weight of fluid equal to its own weight

Pressure

_____ in gas is the amount of force the gas applies; pressure increases by added gas

Boyle’s Law

relationship between pressure and ideal gases

Atmospheric Pressure

pressure (from weight of air) exerted against bodies within the atmosphere

Barometer

device used to measure atmospheric pressure

Pascal’s Principle

change in pressure at one point in an enclosed fluid, will be transmitted to the whole fluid

Temperature

a measure of the hotness or coldness of substances

Thermometer

a device used to measure temperature

Fahrenheit

abs zero -460 °F; freezing 32 °F; boiling 212 °F

Celsius

abs zero -273 °C; freezing 0 °C; boiling 100 °C

Kelvin

abs zero 0 K; freezing 273 K; boiling 373 K

Thermal Energy

total mechanical energy (kinetic and potential) of the particles that make up matter

Heat

flow of thermal energy due to a temperature difference; naturally flows from high temp to low temp

Calorie

amount of heat needed to raise the temperature of 1 g of water by 1 °C

kilocalorie

1,000 calories; a Calorie

First Law of Thermodynamics

heat flow into or from a system is equal to the change in internal energy

Second Law of Thermodynamics

heat never spontaneously flows from a cold substance to a hot substance

Third Law of Thermodynamics

as temperature decreases, entropy approaches a constant value

Entropy

measure of the disorder in a system; naturally increases

Thermal Expansion

increase in volume due to increase in temperature ; conduction, convention, radiation

Conduction

transfer of heat by direct contact

Convection

transfer of heat by fluid motion

Radiation

transfer of heat by light

Insulator

material that resists heat flow

Conductor

material with little resistance to heat flow

Wave

disturbance or vibration propagated from point to point in a medium or in space

Amplitude

the distance from the midpoint to a maximum (crest or tough) on a wave

Wavelength

the distance from one point on a wave to the repetition of that point (crest to crest; trough to trough)

Frequency

number of cycles per unit of time, typically per second

Period

time required for one full cycle, typically in seconds

Wave Speed

how fast a wave through a medium

Longitudinal Wave

a wave that vibrates in the same direction the wave is moving

Transverse Wave

a wave that vibrates perpendicular to the direction the wave is moving

Doppler Effect

the change in frequency of a wave as measured by an observer, due to the relative motion of the source

Shock Wave

the cone-shaped wave created by an object moving at supersonic speed through a fluid

Sonic Boom

the loud sound resulting from the incidence of a shock Wave

Electromagnetic spectrum

the range of electromagnetic waves extending in frequency from radio waves to gamma rays

Opaque

the term applied to materials through which light cannot pass

Reflection

the return of light into the medium from which it came

Refraction

the bending of light when it passes from one medium to another

Convex/converging/positive lenses

cause light to come together at a point

Concave/diverging/negative lenses

cause light to spread away from a point

Diffraction

bending of light due to interaction with an edge

Dispersion

process of separation of light into colors arranged by frequency

Polarization

alignment of light by vibration direction

Electricity

the movement of electrons

Electric current

flow of electric charge transporting energy from one place to another

Voltage

the potential energy present in each electric charge

Resistance

how well a material resists electric charge

Ohm’s Law

the relationship between current, voltage, and resistance

Magnetism

attraction or repulsion between objects having magnetic fields

Magnetic domains

clustered regions of (magnetically) aligned atoms

Generator

device that turns mechanical energy into electrical energy

motor

device that turns electrical energy into mechanical energy

Faraday’s Law

if the magnetic field in a closed loop (of wire) changes in any way, a voltage is induced in a loop