This require uranium to be enriched with the uranium-235 isotope and the chain reaction to be controlled so that the energy is released in a more manageable way.
The isotope uranium 238 is used to estimate the age of the earliest igneous rocks and for other types of radiometric dating.
This technique is not restricted to bones; it can also be used on cloth, wood and plant fibers.
This restriction extends to animals that consume seafood in their diet.
Depleted uranium is used as shelding to protect tanks, and also in bullets and missiles.
The first atomic bomb used in warfare was an uranium bomb.
Some micro-organisms, such as the lichen Trapelia involuta or the bacterium Citrobacter, can absorb concentrations of uranium that are up to 300 times higher than their environment.
Citrobactor species absorb uranyl ions when given glycerol phosphate (or other similar organic phosphates).
After one day, one gram of bacteria will encrust themselves with nine grams of uranyl phosphate crystals; creating the possibility that these organisms could be used to decontaminate uranium-polluted water.
Plants absorb some uranium from the soil they are rooted in.
Since 1955 the estimate for the age of the Earth has been based on the assumption that certain meteorite lead isotope ratios are equivalent to the primordial lead isotope ratios on Earth.
In 1972 this assumption was shown to be highly questionable.
Carbon dating is used to determine the age of biological artifacts up to 50,000 years old.
This technique is widely used on recent artifacts, but educators and students alike should note that this technique will not work on older fossils (like those of the dinosaurs alleged to be millions of years old).