One excellent example of this is the use of radioactive carbon-14 to determine the steps involved in the photosynthesis in plants.
We know these steps because researchers followed the progress of the radioactive carbon-14 throughout the process.
The results showed that Ötzi died over 5000 years ago, sometime between 33 BC. Uranium has a very long half-life and so by measuring how much uranium is left in a rock its approximate age can be worked out.
The answers to these questions can be found in this lesson on the applications of nuclear chemistry.
The 'heavier' atom that is produced is actually lighter than the two individual pieces, which means that mass is lost.
Because mass and energy are tied together, when mass is lost, energy is lost, or emitted.
The methods work because radioactive elements are unstable, and they are always trying to move to a more stable state. This process by which an unstable atomic nucleus loses energy by releasing radiation is called radioactive decay.
So, we rely on radiometric dating to calculate their ages.
Radiometric dating, or radioactive dating as it is sometimes called, is a method used to date rocks and other objects based on the known decay rate of radioactive isotopes.
In most cases, the information is used by physicians to make a quick, accurate diagnosis of the patient's illness.
The thyroid, bones, heart, liver and many other organs can be easily imaged, and disorders in their function revealed.