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What is Radioactivity?

Sometimes the nucleus of an atom is unstable.
A change will occur in the nucleus to make it more stable.
The change is called a decay. When a nucleus decays
it will emit (give out) some particles or waves. Emitting
or waves from the nucleus is called radioactivity.
Radioactive decay
is a random process which gives out heat.

The particles or waves that are emitted (see below) are called
radiation. The same word radiation is also used for some
electromagnetic waves which have not come from radioactive decay.

What are the Three Types of Radioactivity?

There are three types of radioactivity, called alpha, beta
and gamma. A radioactive nucleus will emit either an
alpha particle or a beta particle or a gamma ray. After an
alpha particle or a beta particle has been emitted from a
nucleus, the atomic number of the atom will have changed.
The atom will have changed into a different element.
An alpha or beta emitter might also emit gamma radiation.

s Radioactivity Good or Bad?

Radioactivity can be both harmful and useful.

For example, the rate of decay (called the half-life) can be used
to find out how old things are. The energy released from
a nucleus during fission can be used to generate electricity.

Radioactivity can cause damage to living cells leading to cancer.

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