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What is Radioactivity?

Chemistry | 7-14 yrs | Reading Pod

Definition of Radioactivity

Whenever we talk of radioactivity or radiation, the first thought that fleets across our mind is X-Ray machines and with that the famous scientists Marie Curie and husband Pierre Curie who were awarded the Nobel Prize for their research on radiation.

But radioactivity encompasses more than just x-ray machines and the care to be taken when we are exposed to the rays that are often considered more harmful than good.

Radioactivity is the radiation that is released from an unstable atomic nucleus. Atoms of uranium and plutonium are naturally radioactive atoms.


It is the decomposition of unstable atomic nuclei and thus the energy that is released is called radioactive decay.

The Discovery of Radioactivity

Radioactivity was first discovered in 1896 by the French scientist Henri Becquerel.


The radiation emitted could be in the form of alpha, beta or gamma particles. The alpha particles are positively charged particles, beta particles are negatively charged.

Where it is found?

Radioactive materials are found in nature in soil, water and even vegetation. The sun is a natural source of radiation and x- ray machines are man- made sources that emit a form of energy called radiation.

Uses and Dangers of Radioactivity

  • Alpha particles can cause harm if inhaled or if they enter our body through a wound or a cut in the skin. These particles however can be shielded by a sheet of paper. They can cause damage the lungs, skin and increase the risk of cancer.
  • Beta particles cannot be shielded by paper, they can however be stopped by thicker materials like wood. These too like alpha particles can cause serious hazards and damage bones if inhaled or ingested. As dangerous and frightening as these rays sound, they do have their uses.
  • They are used in laboratories, hospitals and various industries for the purpose of sterilizing.
  • Man – made radiation is seen through our nuclear weapons and x- ray machines.