Microwaves Waves of water Light waves Sound waves

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– – Microwaves Waves of water Light waves Sound waves Hopefully not this one…

– – Microwaves Waves of water Light waves Sound waves Hopefully not this one…

 • A wave is a disturbance or movement that transfers energy through space

• A wave is a disturbance or movement that transfers energy through space or through matter – Ex: sound waves transfer energy through air

 • Energy is the capacity to apply force over a distance • A

• Energy is the capacity to apply force over a distance • A force is a PUSH or a PULL on an object

Let’s look at a wave of water: • The rest position (equilibrium position) is

Let’s look at a wave of water: • The rest position (equilibrium position) is shown by a line. • The highest point is called the crest • The lowest point is called the trough

 • The wavelength is measured from crest to crest or trough to trough.

• The wavelength is measured from crest to crest or trough to trough. • Wavelength is a distance and it is measured in metres.

 • Amplitude is the height of a crest or depth of a trough

• Amplitude is the height of a crest or depth of a trough measured from the rest position. • Ex: A big wave with a high crest and low trough has a large amplitude.

 • The rise and fall of each wave is called an oscillation or

• The rise and fall of each wave is called an oscillation or a vibration. • Frequency is the number of repetitive oscillations that happen in a given time. • It is usually measured in Hertz (Hz) or cycles per second.

 • A water wave moves energy (not matter or water). • Energy is

• A water wave moves energy (not matter or water). • Energy is carried forward by the water wave. • If you are sitting on an inner-tube in the lake, the wave passes underneath you. • The water does not move forward.

 • The matter that waves travel through is called a medium. • Ex:

• The matter that waves travel through is called a medium. • Ex: sound waves travel through air – Air is the medium • Ex: ocean waves travel through water - Water is the medium

 • 1) Transverse Waves – Matter in the medium moves up and down

• 1) Transverse Waves – Matter in the medium moves up and down perpendicular to the direction that the wave travels (ex: waving a rope) • 2) Compression Waves – Matter in the medium moves back and forth along the same direction that the wave travels (ex: sound waves)

Compression

Compression

Did you know? ? • Not all waves need a medium…light waves in space

Did you know? ? • Not all waves need a medium…light waves in space can travel through the emptiness of space (there is no matter at all!) • But sound waves DO need a medium to travel through which means there is no sound in space!