On the other hand, the time it will take a puddle to half-evaporate depends on how deep the puddle is.Perhaps a puddle of a certain size will evaporate down to half its original volume in one day.The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo, or how long stable atoms survive, radioactive decay.The term is also used more generally to characterize any type of exponential or non-exponential decay.
Carbon, hydrogen, nitrogen, oxygen, and some other elements like sulfur and phosphorus together form most life on earth (see Organic chemistry and List of biologically important elements).
Carbon in nature is found in three forms called allotropes: diamond, graphite, and fullerenes. Because the half-life (how long it takes for half of a radioactive isotope to go away) of carbon-14 is 5730 years, It is also a key part of many biological molecules (molecules used in life). Graphite is in many (typically desert) areas, including Sri Lanka, Madagascar, and Russia.
) is the time required for a quantity to reduce to half its initial value.
Nevertheless, when there are many identical atoms decaying (right boxes), the law of large numbers suggests that it is a very good approximation to say that half of the atoms remain after one half-life.
There are various simple exercises that demonstrate probabilistic decay, for example involving flipping coins or running a statistical computer program.