Cancer Patient

Objectives:

  • To be able to describe uses of alpha, beta and gamma
  • To be able to explain what half life is and how it is used in carbon dating
  • To know where background radiation comes from

Timing: 2-3 lessons

Last year you looked at radioactive substances, based around a smoke alarm. Now you are going to look at how radioactive substances are used to treat cancer. You will also look at how radioactive substances are used in the nuclear industry in the "Electricity" section.

Make sure you know what alpha and beta particles are and what gamma radiation is. Which part of an atom does the radiation come from?

Find out how these three types of radiation are used in smoke detectors, tracers in industry and medicine. Use

www.howstuffworks.com

Next you need to find out what happens to nuclei when they spit out alpha and beta particles. Think about what alpha and beta particles are and therefore think about what will happen to the mass and atomic numbers of the decayed nuclei. You should be able to balance and construct simple radioactive decay equations.

Radioactive substances decay - what does this mean? How is radioactivity measured? Now you need to find out what is meant by half life and be able to calculate the half life of a substance from a graph. The following site may help: http://www.colorado.edu/physics/2000/index.pl.

Now use this information to describe how carbon-dating works and how the decay of uranium to lead can be used to determine the age of rocks. The following sites may help:

Your teacher may get you to carry out a couple of practical activities to show how the amount of a radioactive substance changes with time. The first one involves chopping a lump of plastericine in half lots of times and weighing it. The second involves chucking lots of titchy cubes of wood which quite nicely shows you the random nature of radioactive decay but you will lose the will to live before you get to the end!

Remember from last year that we are exposed to background radiation all the time. Go back to

http://www.epa.gov/radtown/enter-radtown.htm or http://www.hpa.org.uk/radiation/understand/at_a_glance/index.htm to remind yourself where it all comes from.

It's not in the exam but you can read about how radioactive substances are used in the treatment of cancer at: http://www.cancerhelp.org.uk/help/default.asp?page=166 or http://www.insidestory.iop.org/insidestory_flash1.html.

You could do the following worksheets:

  • "Atomic structure, half-life"
  • "Alpha-decay and beta-decay"
  • "Radioactivity all around us"
  • "The effects of radiation on living things"
  • "Working with radiation"
  • "Radioactivity and Medicine"
  • "How long?"
  • "Using radioactivity"
  • "Atoms and radioactivity"
  • "Using radioactive decay"
  • "The structure of atoms"