A particle occupies a well-defined position in space, which cannot be simultaneously occupied by another particle. If there is more than one particle in a given region of space, then their sum is equal to the number of individual particles. The sum can neither be more nor less. On the other hand, a wave is spread out in space. Two or more waves can co-exist in the same region. When two waves are present together, the resultant wave can be larger or smaller than the individual waves.
| Wave | Particle |
|---|---|
| Wave is delocalised (spread out) in space | Particle is localised in space |
| Two or more waves can exist in the same region of space | Two particles cannot simultaneously occupy the same position in space |
| When two waves are present together, the resultant wave can be larger or smaller than the individual waves. In other words, two waves may interfere | If there are two or more particles in any region of space then their sum is equal to the number of individual particles. In other words, two particles do not interfere |
Is electron really a particle or wave?
Upto the year 1924, electron was exclusively regarded as a particle. However, in 1924, de-Broglie suggested that an electron behaves both as a material particle and as a wave. Just like light, some experimental facts can be explained by assuming electrons as tiny particles while some other facts can be explained only on the basis of wave character of the electrons. Thus, the electron behaves as a particle as well as a wave.
The electrons are so small that they cannot be seen even with the help of a powerful microscope. But there is no doubt regarding their existence, rather they are the essential constituents of all forms of matter. Thus, they can be imagined to look like very tiny dots executing wave like motion and moving with speed 3 x 108 m/sec.