Cassette tapes or eight-tracks might be the first things that come to mind when thinking about dated magnetic storage, but Bronze Age clay pottery has them both beat.
Acheulean stone tools, named after the site of St Acheul in France where they were first found, became finer and more sophisticated over time.
These tools range from 1.75 million years old (far left) to 0.85 million years old (far right).
Any scientific study of the past, including the geologic past, relies on the use of dating methods to determine the age of sites, landforms, sediments or geologic events.
A variety of dating methods are available, and the scientist must decide which method will provide the most accurate results in each case.
This produces radiation and is particularly prominent with larger atoms that are easily able to fall apart spontaneously, leading to new elements or a lighter form of the original element.
The time it takes for half of the atoms of an element in a sample to decay is known has its half-life.Relative dating methods can not establish exactly how old things are, but only how old things are relative to other things.Relative dating is based on the law of superposition which states that material found at the bottom of a sedimentary sequence is older than the material above it.Relative dating methods were the first dating techniques to be developed, and are still widely used.The radiocarbon dating method was developed in the late 1940's by Dr. Libby, who later won a Nobel Prize in chemistry for this work.An element is defined by the number of protons in an atom’s nucleus.