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  • Created by: helen
  • Created on: 27-06-11 16:41
Preview of Radioactivity

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Everything around us is made up of atoms.
An atom consists of protons, neutrons and electrons. The protons and neutrons are found in the nucleus of the atom (the very small centre) and the electrons orbi
around the nucleus.
Particle Relative charge Location
Proton +1 Nucleus
Neutron 0 Nucleus
Electron 1 Orbiting the nucleus
The number of proton there are in the nucleus of an atom tells us what element it is (or what number on the periodic table it is) eg an atom containing only 1 prot
is always Hydrogen and an atom containing 6 protons is always Carbon.
Sometimes atoms have more energy than they need in their nucleus and so they try to get rid of some of it. It an atom has more energy than it needs in its nucleu
is unstable. Unstable atoms can also be called radioactive.
When an unstable atom gets rid of this excess energy it does it by emitting (giving out) radiation. A radiation can be either a particle or a wave. The process of
emitting radiation is called radioactive decay. Radioactivity is often referred to as nuclear physics as it relates to changes that occur in the nucleus of the atom.
We can try to predict whether an atom is stable or not by looking at the number of protons and neutrons there are in the atom. For small atoms, if the number of
protons = the number of neutrons then it is stable, if the number of protons and neutrons are different then it is most likely to be unstable.
Different versions of atoms that have the same number of protons (ie are the same element) but have different number of neutrons are called isotopes. Unstable
isotopes are called radioactive isotopes or radioisotopes.

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There are three main types of nuclear radiation, these are alpha, beta and gamma.…read more

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If smoke Can be used as a tracer either in the body or in water pipes etc. A small amount
particles get I the way, the circuit of gamma source is introduced into the vessels and a gamma detector is placed
is broken and sets off an alarm. over them. If a normal level of gamma is detected then the vessels are free
flowing. If very high level is detected then there is a blockage or leak at that
point.…read more

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Some isotopes tend to emit radiation very quickly and this means that they have a short half life. Some isotopes emit their radiation very slowly this means that t
have a long half life.…read more

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When rocks are formed, they contain a known % of radioactive uranium. The half life of this radioactive uranium is about 4500million years. Uranium eventuall
decays to lead. So if we compare the amount of lead to the amount of uranium we can find out how much uranium has decayed and calculate roughly how old th
rock is.
Eg in a very small sample there are 30 atoms of lead and 30 atoms of radioactive Uranium.…read more


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