How is the half-life of a radioactive substance calculated?

The half-life of a radioactive substance is calculated by measuring the time it takes for half of it to decay.

In more detail, the half-life of a radioactive substance is a measure of the time it takes for half of the atoms in a sample to decay. It is a statistical measure, meaning that it is not possible to predict when a single atom will decay, but it is possible to predict how long it will take for half of a large number of atoms to decay.

To calculate the half-life, you would start by taking a sample of the radioactive substance and measuring the amount of radioactivity it emits. This is usually done with a device called a Geiger-Muller counter, which can detect and count the number of radioactive particles emitted by the sample. You would then wait for a period of time and measure the radioactivity again.

The half-life is the time it took for the radioactivity to decrease by half. For example, if you started with a sample that emitted 1000 particles per second, and after one hour it was emitting 500 particles per second, the half-life of the substance would be one hour.

It's important to note that the half-life is a constant for each radioactive substance. This means that no matter how much of the substance you have, it will always take the same amount of time for half of it to decay. This property makes the half-life a very useful tool in a variety of fields, including archaeology, medicine, and nuclear power.

In summary, the half-life of a radioactive substance is calculated by measuring the time it takes for the radioactivity of a sample to decrease by half. This is done by measuring the radioactivity at two different times and calculating the time difference.