Waves

A wave transfers energy from one point to another.

There are 2 types of waves: TRANSVERSE & LONGITUDINAL.

Light, Radio and Water waves are transverse. Sound waves are longitudinal.

In transverse waves the particles move at 90° to the wave direction and in longitudinal waves the particles move in the same direction of the wave.

Diffraction

Diffraction is the bending of waves around obstacles.

Longer wavelengths diffract more than shorter wavelengths.

More Diffraction from smaller gaps.

Sound

Sound levels are measured in decibels (dB).

Regular exposure to noise levels above 85-90 dB can cause damage to hearing.

90 dB and above are examples of noise pollution.

Ultrasound

Ultrasounds are sounds above the range of human hearing (20 Hz - 20,000 Hz)

An ultrasound scanner can be used to examine the inside of a patient. A signal is sent out and then reflected back to the scanner.

Reflection

Law of reflection: The angle that the incoming ray makes with a flat mirror is always the same as the angle it is reflected at.

The normal is an imaginary line that we draw at 90° to the object.