180 likes | 323 Views
Waves. Indian Ocean 2004. Indonesia 2005. Waves. Waves are everywhere in nature – sound waves, visible light waves, earthquakes, water waves, microwaves…. What do you know about waves?. Longitudinal Waves.
E N D
Waves Indian Ocean 2004 Indonesia 2005
Waves Waves are everywhere in nature – sound waves, visible light waves, earthquakes, water waves, microwaves… What do you know about waves?
Longitudinal Waves In this type of wave, particles vibrate back and forwards along the direction the wave is travelling.
Transverse Waves This type of wave moves perpendicular to the motion of the particle
Standing Waves Maybe you've noticed or maybe you haven't. Sometimes when you vibrate a string, or cord, or chain, or cable it's possible to get it to vibrate in a manner such that you're generating a wave, but the wave doesn't propagate. It just sits there vibrating up and down in place. These are called standing waves. These specialized waves have places where the medium does not vibrate at all, called nodes, and other places where the medium vibrates the most, called antinodes. Standing waves have a changing numbers of nodes and antinodes.
Properties of Waves • What is meant by the axis of a wave? The axis is the line running through the middle of the wave pattern.
What is meant by the crest of the wave? The crest is the top part of the wave
…and the trough? The trough is the bottom part of the wave.
What is the amplitude of the wave? The amplitude is the distance from the axis to the crest
Definition of Wavelength? The wavelength is the distance after which the wave pattern repeats itself – the distance between two identical points on the wave
Frequency • The frequency of the wave is the number • of waves each second. • It is measured in hertz (Hz) which just • means “per second”.
Period • The period of a wave is the time taken • for one complete wave to pass a point. • It is measured in seconds (s).
Frequency • The link between the frequency and • period of a wave
Period • Rearrange to find period • T= n • n=cycles f
Draw a Wave • Position/Amplitude = 6cm • Period = 2s • Position/Amplitude = 5cm • Period = 6s • Position/Amplitude = 12cm • Period = 10s • Position/Amplitude = 4cm • Period = 8s