Characteristics and Nature of Wave

Sound is a result of vibration. The vibration is produced by a source, travels in the medium as a wave and is ultimately sensed through the ear - drum. Sound travels like a wave. A medium is a must for mechanical waves like sound to travel.

In contrast, we can receive electromagnetic waves from distant stars and artificial satellites in space as electromagnetic waves need no medium to travel. A wave involves a periodic motion, movement that repeats itself. It also transports energy.

What happens if you throw a stone in a pool of water? You will see a disturbance of a circular shape moving from the point of fall of the stone outwards. The disturbance is made up of a raised ring in water which seems to travel outward. Soon there is another similar circular feature originating at the same centre and moving outward. This goes on for quite some time. Even though there appears to be a movement of material, actually it is only the position of the disturbance that is changing. This is a wave and is made up of the raised part (crest) and low part (trough).

So, crest and trough are essential components of a wave. A wave transfers energy from one point to the other without the medium particles moving from one point to the other.

Understanding the nature of sound requires observations. We observe a flute player continuously shifting fingers over holes to produce different notes while playing a tune. Similarly a sitar player also keeps pressing the string at different points touching different frets. When you strike an empty glass with a spoon and when you strike one filled with water, different notes are produced.

The science of sound helps us in understanding the reasons behind such things. Besides, the understanding of sound has enabled scientists to devise gadgets which are very useful. These include hearing aids, sound instruments like speakers, sound recording and sound amplifying devices.