What is the difference between a longitudinal and a transverse wave?

Waves that go up and down in a curvy shape like you would draw on a piece of paper are called transverse waves. Scientifically, these are when the particles move in a direction that is perpendicular (90) from the direction that the wave is moving (and the direction that energy is being transferred). An example of a transverse wave is an electromagnetic wave.Longitudinal waves are different because the particles are moving forwards and backwards parallel to the direction of the wave (and the direction that energy is being transferred), like when you push a pulse along a slinky. There are areas when the wave is compressed and all the particles are closed together, and areas when it is more spread out (called an rarefaction).