By plotting a graph of count-rate against time the half-life can be seen on the graph.This would also work if you plotted the number of parent atoms against time.
We cannot predict exactly which atom will decay at a certain time but we can estimate, using the half-life, how many will decay over a period of time.
The half-life of a substance can be found by measuring the count-rate of the substance with a Geiger-Muller tube over a period of time.
Radioactive substances will give out radiation all the time, regardless of what happens to them physically or chemically.
As they decay the atoms change to daughter atoms, until eventually there won't be any of the original atoms left.
The longer the half-life of a substance the slower the substance will decay and the less radiation it will emit in a certain length of time.
The following radioactive substances contain 1000 unstable atoms. Click on the up and down buttons get to the number of unstable atoms remaining after the length of time shown.The Carbon-14 within a living organism is continually decaying, but as the organism is continuously absorbing Carbon-14 throughout its life the ratio of Carbon-14 to Carbon-12 atoms in the organism is the same as the ratio in the atmosphere.Once an organism dies it stops taking in Carbon in any form.Different radioactive substances can be used for different purposes.The type of radiation they emit and the half-life are the two things that help us decide what jobs a substance will be best for.This is a slide and worksheet for radioactive dating and half life activity.