Volume – louder and softer
Sound vibrations travel as waves. Like waves in water, the waves get smaller the further they travel (unless something acts to boost them), so the closer we are to the source of a sound, the louder it is. As we move away from the source, the sound vibrations get smaller – and smaller means softer – so the volume of sound that reaches our ears diminishes.
Pitch – higher and lower
The frequency of the vibration determines the pitch of the sound – how high or low it sounds. Frequency is the rate at which a regular event occurs. In the case of sound, this relates to the number of repeating cycles of a sound wave passing a point per second.