Front

Iodine-131 has a half-life of 8 days. After 32 days, how much of your original iodine will be left?

Back

6.25%

Front

Based on the graph, how much of a substance is left after 2 half-lives?

Back

25%

Front

Half-life

Back

The time it takes for half of the radioactive material in a sample to decay

Answer explanation

After one half-life, half of the radioactive material in your sample will have decayed into a daughter isotope.

Front

Based on this graph, about how long is the half-life for Mercury-203? Options: 400 days, 250 days, 150 days, 50 days

Back

50 days

Answer explanation

A half-life is the amount of time it takes for 50% of the parent isotope to change to the daughter isotope. In other words, when the lines cross, that's one half life.

Front

Over time, what happens to the amount of parent isotope?

Back

It decreases.

Front

Over time, what happens to the amount of daughter isotope?

Back

It increases.

Front

What is the best way to find the age of animal bones from a cave?

Back

Carbon dating

Front

What is the best way to find the age of a very old rock formation?

Back

Uranium dating

Front

An archaeologist uses carbon-14 dating to determine the age of wood from a very old shipwreck. She finds that about 50% of the original carbon-14 is left. How old is the ship?

Back

About 5,700 years

Front

A radioactive atom breaks down to release energy and particles. What is this process called?

Back

Fission