FTCE Science K-6 (energy, waves)

wave

a disturbance that moves through space and time.

carry energy from one place to another, but waves do not carry matter from one place to another

electromagnetic waves

vibrations of electric and magnetic fields.(radio waves, light)

medium

material that carries a mechanical wave

period

the time it takes to complete one full wave cycle and is measured in seconds.

wavelength

is the length of one complete wave cycle and is measured in distance units. (ex. distance from the top of one wave crest to the top of the next wave crest)

frequency of a wave

number of full cycles that happen each second.

A high frequency wave has a short period since it vibrates very rapidly, and a low frequency wave has a long period since it vibrates more slowly.

wave speed

how fast the wave energy moves from one place to another

the speed of all electromagnetic waves in a vacuum is the same as the speed of light.

Mechanical waves travel much more slowly, and at many different speeds.

transverse wave,

the direction of the vibration is perpendicular to the direction the energy travels, that is, the vibration is up and down or side to side when the wave travels forward

crests

peaks of transverse waves

troughs

lowest points of transverse waves

amplitude

maximum distance particles of the medium move away from their normal (non-vibrating) positions.

the more energy, the greater the amplitude.

longitudinal wave

direction of vibration is parallel to the direction the energy travels

sound wave

longitudinal compression waves, meaning the wave energy creates areas of high and low pressure, or high and low density.

need a medium, or a material that carries the wave

intensity

related to the amount of energy transported by the wave and is measured in decibels (dB).

loudness

human perception of the intensity

threshold of hearing

A sound of 0 dB, softest sound a human can hear.

threshold of pain

A sound at 120 dB

pitch

how high or low the notes sound

High-frequency sounds are heard as a high pitch while low-frequency sounds are heard as a low pitch.

Doppler effect

In the Doppler effect, when observer or object approach, wavelength is shorter, while frequency and pitch are higher. When they move apart, wavelength is longer, while frequency and pitch are lower.

Light

a form of electromagnetic radiation

dual nature

light, a particle nature and a wave nature

higher frequency light

has more energy

shorter wavelength

higher frequency

longer wavelength

lower frequency

energy

ability to create heat or do work

Kinetic energy

energy of motion

Potential energy

stored energy

mechanical energy

the sum of an object's potential and kinetic energy in a mechanical system

Fossil fuels

formed from the remains of long-dead plants, which had captured the sun's energy through photosynthesis when they were alive

non-renewable resources

Burning fossil fuels also causes air pollution

Turbines

transform energy into kinetic energy

generator

turns rotating kinetic energy into electrical energy.