4.9 What is a Wave Lesson

• ​disturbance - something that moves another thing out of place

• energy - the power to do work

• medium - matter in which something is carried

• ​crest - the top part of something

• microwave - an energy wave that is shorter than a radiowave

• signal - a radio wave sent or received

• visible - able to be seen

• wavelength - the distance between one crest of a wave and the next

​Visible light is the light we can see.
A rainbow breaks up white light into the colors of light it is made of.

ROY G. BIV - Red Orange Yellow Green Blue Indigo Violet

​amplitude - the distance from a place of rest to the crest of a wave

decibel - a unit used to measure sound

Sound - vibrations that travel through the air or another medium and can be heard when they reach a person's or animal's ear.

​Sound can be dangerous - If we listen to sounds above 85 decibels over time it can damage our ears.
Sounds above 120dB can cause immediate damage.
Protecting your ears - turn volumes down and if in a noisy place wear ear protection.

​Sound travels as a longitudinal wave.

Sound is made by vibrations.

A speaker moves back and forth to make sound.

Frequency is how many waves pass a point in 1 second. It is measured in Hertz.