Telecommunication. Sound Waves.
• Sound energy travels in the form of waves. • Sound can travel through solids , liquids and gases by vibrating the particles in the three types of materials.
Telecommunication. Sound Waves.
• The particles in the three materials vibrate in the same direction as the wave motion. • This wave is called a Longitudinal Wave
Sound waves cannot travel in a vacuum.
Telecommunications. Sound Waves.
• These waves then vibrate our ear drums which then activate small bones in our inner ear. • A diagram of the ear is shown.
Telecommunication. The Ear.
bones
Ear drum Outer ear
Telecommunication. The difference between sound and light waves.
• Sound waves travel very much slower than light waves. • This can be seen by observing a thunder and lightning storm. • The light reaches us quickly but the sound from the thunder comes later.
Telecommunication The speed of sound.
• The speed of sound can be measured by by using two microphones and an electronic timer. • When the sound reaches the first mic, the timer starts.When the sound reaches the second mic, the timer stops. • If we know the distance between the two mics (say one metre) and the time , we can work out the speed.This is shown on the next slide.
TELECOMMUNICATION. THE SPEED OF SOUND.
Time = 0.003s
Mic 1
Mic 2 Distance = 1 metre
Sound here
Telecommunication. Calculation of The Speed of Sound
• The Speed of Sound can be calculated as shown below. • Speed = distance time = 1/0.003 = 330 m / s
Telecommunication. The difference between sound and light waves.
• Light is a transverse wave.The particles move at right angles to the wave as shown.