In this and in the following chapter, we will study waves. Waves are a very
important and essential part of our lives. We use them to communicate and see
the world around us. Sound and light are examples of waves. When you speak, you
disturb the air inside your mouth and this disturbance moves through the air to the ear of your friend. Air particles in your mouth do not travel themselves to the ear of your friend, rather, the disturbance is the thing that travels form one point to another. Another example of waves is the waves produced when you throw a stone on
a water surface. The water particles move up and down but do not travel across the surface of the water. It is the disturbance produced by the stone that travels across the water surface,often, over very long distances. The study of waves is simply the study of the motion of these disturbances.
One way of moving information from one location to another
is by moving physical objects, for example a letter, between the two locations.
Alternatively, information or energy can be transferred between the two
locations by waves. No physical objects are moved between the two locations,
but the medium between the two locations is disturbed and forced to vibrate.