# Waves Basics

There are two types of wave motion, transverse where the oscillation direction is at 90 degrees to the travel, and longitudinal where the oscillation and travel directions are along the same straight line. Light is transverse, sound is longitudinal. Earthquake waves can be both.
Have a look at this animation. Compare the two different types of oscillations and also their speeds.

This is a really great little site that you can play around with waves on. ..

For basic wave theory from Absorb Physics,  I think this one is brilliant. Click here and get involved.  Can you get the exercises right?

For a slightly higher level treatment, check out this  animation fromWikipedia

All waves obey two simple equations.

Speed of wave = frequency x wavelength

Make sure that the units match on both sides

where frequency is the number of complete waves made every second and wavelength is the crest-to crest distance

Speed = distance travelled / time taken

Earthquakes can be incredibly devastating. The 2005 ‘quake in northern Pakistan killed over 80,000 people injured another 100,000 and made over 3 million people homeless.

More detailed science to follow. The water ripples in the picture above  overlap each other. Watch this space.