Our planet is far older than people had thought! Students can understand the mechanism of radioactive half-life and how it helps determine age by experimenting with pennies, dice, and sugar cubes ...

Key fact Half-life is the time it takes for the activity of the source to fall to half its original value. The illustration below shows how a radioactive sample is decaying over time. From the ...

This rate of decay is constant for a given isotope, and the time it takes for one-half of a particular isotope to decay is its radioactive half-life. For example, about 1.5 percent of a quantity ...

Radioactive isotopes are typically used by ... such as cosmogenic beryllium-10." The isotope's half-life is a whopping 1.4 million years, and breaks down into boron, allowing scientists to look ...

Since the output of the resulting cells will be in proportion to their radioactivity their life will be in the same order of their radioactive half-life. 5730 years for half-capacity in the case ...

the material would present an unreasonable public health threat from radon gas emissions that would continue for generations given their radioactive 1,600-year half-life. In addition to radionuclides, ...