Page 104 - (DK) Danger! Open with Extreme Caution!

RADIOACTIVE!

Everything we know about radiation has been discovered only in the past 100 years
or so. In large doses, it is one of the most dangerous discoveries ever known, but,
through trial and error, we’ve figured out that small doses of radiation can be utilized
for positive, sometimes life-saving, effects.

What is radioactivity? released from Nucleus
Most atoms have stable nuclei—the number of
neutrons and protons in the nucleus stays the same.
Particle
But others, such as uranium atoms, have unequal
the nucleus
numbers of neutrons and protons. This makes them
unstable and liable to break down. When an unstable
atom decays (breaks down), it releases particles from
its nucleus. This release is called radioactivity.

Powerful particles
There are three main types
Thin copper
of radiation: alpha, beta, and
Thick paper
Thick lead
gamma. Alpha radiation is
Alpha radiation the weakest type, struggling
to pass through a thick sheet of
Beta radiation
paper. Beta radiation is stronger
but meets its match in a thin
sheet of copper. Only a thick
sheet of lead or concrete can
block the most penetrating
Gamma radiation
type of radiation, high-energy
gamma rays.

Discovering radioactivity
French scientist Antoine Henri Becquerel discovered
radioactivity by accident in 1896 when he found that
uranium salts emitted rays capable of penetrating black
paper. Working in Becquerel’s lab, Marie Curie and her
husband, Pierre, duplicated his experiment in 1897 and
named the phenomenon “radioactivity.” The Curies
devoted their lives to understanding radioactivity,
and in 1903, all three scientists shared
the Nobel Prize for physics.

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