Radium watch hands, close-up view

A demonstration of radioluminescence caused by very small quantity of radium salt mixed with a fluorescent material (probably copper activated zinc sulfide) in radium watch hands.

The fluorescent material has degraded considerably but faint radioluminescence can still be seen in total darkness once the eyes have accustomed to it, and is visible as scintillations when viewed through 20x loupe. The scintillations are caused by alpha particles (helium nuclei - 2 protons and 2 neutrons) bombarding the fluorescent material.

The image intensifier was used to amplify the image so it could be taken with a camera.

Category:

Science & Technology

Tags:

• radium
• watch
• hands
• radioactive
• decay
• ionizing
• radiation
• spinthariscope
• glow
• in
• the
• dark
• alpha
• particles