Waves

What is a wave?

A wave is a vibration. We can also say that a wave is an undulation, a rising and falling movement.

Lets look at the features of a wave:

Definition of terms:

Crest- the peak of a wave.

Trough (Tra.a.a.f)- the bottom of a wave i.e the depression.

Amplitide- the height of a wave/vibration, measured in metres (m). For sound waves, this determines the loudness.

Frequency- the number of vibrations per second. For sound waves, this determines the Pitch of the sound i.e. more waves= higher pitch. So how many waves/vibrations are above?

Frequency is measured in Hertz i.e. Hz ( also kiloHertz: kHz, MegaHert: mHz)

1 Hz = 1 Vibration per second

Remember: kilo means 1000, mega means 1 000 000

Application:

Look at the picture above. How many waves does the radio receive per second from this Radio Station?

Longitudinal and transverse waves

1. Longitudinal waves- vibrate from side-to-side. The vibration is in the same direction as energy passes from one end of the wave to another.

2. Transverse wave

Transverse waves vibrate perpendicular (at 90⁰) to the direction of energy transfer. In simple terms, they vibrate up and down.

Examples:

1. Longitudinal waves

-Sound waves

-Sound waves need a material to travel through- they need vibrating particles.

2. Transverse waves

Electromagnetic waves. This includes: Light, microwaves, radiowaves, infra-red waves, gamma rays.