# 3 radioactive elements in absolute dating

For example, in 1991, two hikers discovered a mummified man, preserved for centuries in the ice on an alpine mountain.

Later called Ötzi the Iceman, small samples from his body were carbon dated by scientists.

Rontgen used the mathematical symbol for unknown to name this energy X-rays.

The interest in Rontgen’s discovery would launch the second scientific revolution; the first being launched by the work of Galileo (Asimov, 1984, pp 514-515).

This shows we should not trust radiometric dating, right? The potassium-argon method, with its long half-life of 1.3 billion years, should not be used to date rocks that are only 25 years old.

These people have only succeeded in correctly showing that one can fool a single radiometric dating method when one uses it improperly.

Trees undergo spurts in growth in the spring and summer months while becoming somewhat dormant in the fall and winter months.

When a tree is cut down, these periods are exhibited in a cross section of the trunk in the form of rings.

Once this energy was discovered a new, successful strategy called radiometric dating would be developed.

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.

Example: The radioactive element carbon-14 has a half-life of 5750 years.

Today radiometric dating places absolute dates on the relative time scale.

Wilhelm Konrad Rontgen (1845-1923) published a report in 1895, which described his discovery of a mysterious source of energy emitted by a cathode ray tube.