Radioactivity

Radioactivity is the process by which an unstable atomic nucleus loses energy by radiation. This process was discovered in 1896 by Henri Becquerel. A material that spontaneously emits this kind of radiation, which includes the emission of energetic alpha particles, beta particles, and gamma rays, is considered radioactive.

Discovery

Radioactivity was discovered in 1896 by French scientist Henri Becquerel, while working on phosphorescent materials. These materials glow in the dark after exposure to light, and he suspected that the glow produced in cathode ray tubes by X-rays might be associated with phosphorescence. He wrapped a photographic plate in black paper and placed various phosphorescent salts on it. All results were negative until he used uranium salts. The uranium salts caused a blackening of the plate in spite of the plate being wrapped in black paper. These radiations were given the name "Becquerel Rays".

Types of Decay

There are three main types of radioactive decay: alpha decay, beta decay, and gamma decay, classified by the type of radiation emitted.

Alpha Decay

In Alpha decay, the radioactive atom emits an alpha particle. An alpha particle is defined as a positively charged particle of a helium nucleus.

Beta Decay

In Beta decay, the radioactive atom emits a beta particle. A beta particle can either be an electron or a positron.

Gamma Decay

In Gamma decay, the radioactive atom emits gamma rays. Gamma rays are high energy photons.

Health Effects

Exposure to Radioactivity can cause damage to living tissue, and can lead to mutations, radiation sickness, cancer, and death.

See Also

• Nuclear physics
• Nuclear power
• Nuclear weapon
• Radiation therapy
• Radiation protection

References

Radioactivity Resources
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