Our Radioactive World

Welcome to our radioactive world! Here, you’ll find information, games, and resources all about radioactivity and its uses in our day-to-day lives. For teachers, we’ve also got downloadable versions of the RAD Ratings cards used on this website, as well as lesson plans and PowerPoint presentations to help implement the activities here into classrooms. So have a look around; we hope you enjoy your exploration into the world of radiation!

What is an atom?

To understand what radiation is, we must first understand atoms. Atoms are tiny bits of matter – we can’t see individual atoms with our eyes, but lots of them together make up everything we see around us, from buildings to cars, and plants to our own bodies! Each atom is made up of a bundle of protons and neutrons, called the nucleus, with electrons spinning around it.

Where does radiation come from?

If the nucleus has roughly the same number of protons and neutrons then it is stable, but if it has too many protons, too many neutrons or too many protons and neutrons combined then it is unstable and emits radiation as either particles or energy. Certain elements, like uranium, only have unstable isotopes, whilst other elements, like carbon, have isotopes that can be stable or unstable. Unstable isotopes (collectively called radionuclides or radioisotopes) are radioactive and emit radiation.

What are the types of radiation?

• Alpha (α) radiation – Heavy, slow-moving particles made of 2 protons and 2 neutrons. Because they are slow moving, they are easily blocked by most things but can be dangerous if they get inside the body. They are stopped by a few centimetres of air, paper, etc.
• Beta (β) radiation – Lighter, faster moving particles made of just 1 electron. These are harder to shield against but are generally less dangerous.
• Gamma (γ) radiation – High-energy ray. They have no mass and so are very difficult to shield against – they are only slowed by very dense materials like thick metals or concrete.
• Other types of radiation such as neutron or positron radiation exist, but these are much rarer.

What is half-life?

We can work out how long a radionuclide will exist for by looking at its half-life. A half-life is the time taken for half of a radionuclide to decay into another isotope. For example, caesium-137 has a 30-year half-life, so if a block of caesium-137 was created this year then in 30 years’ time only half of the block would still be caesium-137 (the rest will have decayed into barium-137), in 60 years’ time only a quarter of the block would still be left (as it’s half of the remaining half block), in 90 years’ time only an eighth would remain (as it’s half of the remaining quarter block), etc.

Understood all that? Great. Now it’s time to check out the topics at the top of the page to start your journey through our world of radioactivity!