Question: How can you explain a half life?

Sarah Hunak answered on 16 Nov 2016:

A half life is the time taken for a radioactive material to lose half of it’s activity. So when something is radioactive, it gives off radiation ,and the amount of radiation is called its activity. Over time, this activity falls and the radioactive particles stop being radioactive. If the half life of a radioactive material is for example 5 years, then if the starting activity was 100 Bq (Bequerel is the unit of radiation), then after 5 years, the activity would be 50 Bq. Then after another 5 years, so 10 years in total, it would be 25 Bq, after another 5 years, 17.5 Bq and so on.

the half life of a radioactive material depends on what the material is. Some have half lives of only a few seconds, some have half lives of thousands of years!

It’s not the easiest subject to get your head around, you’ll learn more about it when you do your GCSEs, but great question, thanks!