Waves

If I said waves, what appears in your mind? The ocean? Probally, but I am talking about other waves too. There is a whole world of waves, and they all fall under two catagories, transversal waves and longitudinal waves. And you can break those waves up into two other catagories, mechanical waves, waves that require a medium to travel through, and electromagnetic waves do not need a medium to travel through.Transversal waves move at right angles to the direction in which all waves travel. And longitudinal waves move prallel to the direction in which the waves travel.

The Anatomy of a Transversal Wave
Transversal waves comes from the word transverse, which means across. In a transversal waves, the particles of the waves move across traveling in the direction in which the wave travels. The rest point of a transversal wave is point when the medium is not moving or is still. The amplitude of a transversal wave is determined by how high or low the wave is from its rest point. The crest of a wave is the highest part of a wave. The trough of a wave is the lowest part of a wave. From the rest point to the crest is a positive amplitude. From the rest point to the trough is a negative amplitude. From crest to crest or trough to trough measures a wavelength. The greater the energy disturbance is, the greater the frequency of the wave is.
If you had a rope, and some one were to be holding one end of the rope and you held the other, that rope would be in its rest point. If you grasped the rope in one hand and you flicked is once per second, your partner wouldn't be able to hold the rope still. Why? Because the energy you inflicted on the rope, travels down the rope and enters your partner. Even if you flick your hand the slightest amount, your partner still wont be able to keep their hand still.

The Anatomy of a Longitudinal Wave
A longitudinal wave is a wave which moves the medium parallel to the direction in which the wave travels. The best example of a longitudinal wave is a slinky. If you hold onto one end of the slinky, and push and pull with the other end of the slinky, you can see "pulses" traveling down the slinky. The "pulses" are compressions. Compressions mean what they sound like. Compressions are parts where the coils are closed together, or are compressed. The parts of the slinky that is spread out are called rarefractions. One wave length on a longitudinal wave is measured from the end of one compression, to the beginning of another.
If you took a slinky and placed it on the floor with you partner holding one end of the toy, and you pulled back and pushed foward, you can see the coils compress and rarefract. But unlike the rope scenerio, your partner will be able to hold the slinky still. Why? Because only some of the energy will get transfered into your partner. Some will turn into heat energy. And some will reflect back. Its like if you threw a bouncy ball at the wall. You throw it with a certain amount of energy, but when it comes back its weaker, thats because some of the energy dissapated from the object.