Radioactive Materials • Elements that emit radiation all the time are called radioactive • Radioactive elements that are found in the world around us emit background radiation • Background radiation comes from rocks, food, outer space etc
Radioactive Materials • If you are contaminated then you are carrying a source of radiation on your person • Irradiation means to fire radioactive particles at food, medical instruments to sterilize them. • There are three types of radiation Alpha, Beta and Gamma
Radioactive Materials • Ionising radiation damages living cells • When ionising radiation strikes living cells these may be killed or may become cancerous • Ionized molecules react more quickly
Radioactive Materials • alpha radiation is most likely to cause damage • gamma radiation is least likely to cause damage • Alpha stopped by paper • Beta stopped by Aluminium • Gamma stopped by lead
Radioactive Materials • ionising radiation can be used to:treat cancer • sterilise surgical instruments • sterilise food • You need to explain why?
Radioactive Materials • recall that radiation dose in measured in sieverts is a measure of the damage done to your body • Apply the ALARA principle to radiation • Apply the precautionary principle to radiation • Suggest ways to reduce risk
Radioactive Materials • Explain the difference between perceived risk and actual risk • Account for the difference between perceived risk and actual risk • The rate of radioactive decay cannot be changed • The nucleus of the atom is unstable ( has too much energy ) so gives out particles
Radioactive Materials • Half life what does it mean? • Calculate the activity after a number of half lives • The activity of a radioactive source get less with age,
Radioactive Materials • Power stations • Fuel Uranium, process fission • Chain reaction controlled by Control Rods • Radioactive waste • Lots of energy from a small amount of Uranium • Learn how a nuclear bomb works
Radioactive Materials • Why produce electricity • Easy to transport around • Can be used in many different ways • It is a secondary source of energu • Renewable sources of energy geothermal wind power etc • Fossil fuel power stations produce CO2
Radioactive Materials • Advantages and disadvantages of different types of power stations • Can things be made totally safe?