What is meant by amplitude and intensity of sound?

In the context of sound, the amplitude is the size of vibrations, determining how loud a sound is to be. Put it simply, the amplitude is the height of the peaks of a sound wave. Let’s try to understand the concept with the example of the sea. Sometimes when you visit it, the sea looks calm. But sometimes, it gets rough with huge waves. As the waves develop, we can see some parts dipping down lower than the normal surface of the water, and others rising higher than the same. The distance between this dip or the rise of a wave from the calm surface is generally referred to as amplitude. We know for a fact that larger vibrations create louder sounds. 

Intensity describes the amount of energy in a sound. For example, a pistol shot has more intensity and produces more sound compared to a cork being pulled off a bottle.