Particle - Antiparticle Annihilation

Bring a particle of matter next to a particle of antimatter and they will annihilate each other. Their mass will be converted completely into electromagnetic radiation.


A used, single use flash camera. You can often get these for free from your local photo processor.

Make sure there is a battery in the camera.

A box with a piece of white paper.


Remove the back from the camera.

Notice that inside the back there is a toothed wheel. Rotating the wheel to the right produces clicking noises and cocks the camera so that when you hit the shutter release it goes click.

Practice cocking and firing the camera.

In the front of the camera there is a button used to charge the flash unit. Hold down the button until the flash is charged.

Cock the camera. When you press the shutter release button, the flash should fire.

Warning!, do not remove the front of the camera, there are wires inside the front which carry several hundred volts. If you touch these wires you could get a nasty shock.

To Do and Notice

Hide the camera inside your shirt.

Hold up the index finger of your right hand and say "If I have a proton on the tip of this finger."

Then hold up the index finger of your left hand and say "and an anti-proton on this finger. And then bring them together."


As you bring the matter and antimatter together in front of the paper, surreptitiously press the button on the flash camera with ypour right thumb causing a bright flash of light.

Notice how the audience is startled.

What's Going On?

When a particle of matter such as a proton, meets a particle of antimatter, an anti-proton, the two annihilate each other and turn into energy, a flash of light.

Going Further

Flash units for Single Lens Refex cameras will produce more light and a more spectacular effect. These often have a button or connector plug that allows them to be manually triggered. If you can find one of these units use it in place of the smaller flash unit from the disposable camera.

Scientific Explorations with Paul Doherty

© 2000

21 Nov 2000