Ionising radiation

• A Geiger-Müller detector can detect ionising radiation
• Background radiation comes from:

  • cosmic rays - radiation reaching earth from space
  • rocks and soils - som rocks are radioactive and give off radon gas
  • living things - plants absorb radioactive materials from the soil and these pass up the food chain
• The activity of a radioactive source decreases over time and is measured in becquerels (Bq)