Not quite something, not quite anything either, the particle is so small that it is sometimes said that it doesn’t even have a size.

It also has wave properties. The wave is not tangible like the sound waves or the sea waves, it represents it’s probability of presence in the space. This paradoxical behaviour is known as the wave-particle duality.

Fig. 1  – Particles interaction

Fig. 2  – The wandering particle is free to move in all directions.

It’s not possible to determine jointly and accurately the momentum (speed) and the position of the particle. It is subject to uncertainty:

With time, Δx increases, the uncertainty increases, its wave function propagates according to 

The particle can’t be represented. It is generally studied through its interactions rather than by itself.

Fig. 3  – Angular dependence of wave phenomena


     Some particle collisions give rise to a particle of light: the photon. The particle thus created doesn’t pre-exist the collision. It is created from scratch by the energy of the collision. The energy of the incident particles becomes matter.


In the following images the camera acts as the detector.
Thanks to its sensitivity to photons (particles of light), it reveals the collisions between a wandering particle (the photographer) and his photographic subject.





Many of the particle that are created disintegrate very quickly. The particles that are detected are those that are stable long enough to leave a mark in the detectors.








The waves add up and then






separate without deformation.