Uses of Radioactivity

  1. Gamma rays are used to kill bacteria specially in sterilizing medical equipment and in preserving food. (medicine)
  2. Alpha particles are used in smoke alarm for smoke detection. Alpha particles have high ionization effect and therefore they ionize the air molecules in between the two metal plates allowing the current to pass through. When smoke enters between the plates, some of the alpha particles are absorbed causing less ionisation to take place.

This means a smaller than normal current flows so the alarm switches on. (safety and security)

  1. Beta particles are used to monitor the thickness of the paper or metal sheets in manufacturing factory. Some of the radioactivity is absorbed by the foil and some passes through to the detector.

The thicker the foil, the less radioactivity passes through it to the detector. The amount of radioactivity arriving at the detector is monitored by the computer. The thickness of the foil is controlled by the gap between the rollers. (industry)

  1. Carbon-14 is used to find the age of living organism or plants. This method is called radioactive carbon dating. There’s a small amount of radioactive carbon-14 in all living organisms. When they die no new carbon-14 is taken in by the dead organism. The carbon-14 it contained at the time of death decays over a long period of time. By measuring the amount of carbon-14 left in dead organic material the approximate time since it died can be worked out. (archeology)
  2. Uranium -238 which eventually decays into lead is used to find the age of igneous rock. (archeology).
  3. In radiotherapy the high doses of gamma radiation are used to kill the cancer cells. (medicine).
  4. Find leaks or blockages in underground pipes. (construction)