The world is made of tiny building blocks called 'elements'. Scientists have worked out how fast some elements change into other elements. That gives us a very big clue about how old the Earth is.
The periodic table is one of the classic images of science that is found in labs as well as on t-shirts, mugs, even set to music. But what exactly is the periodic table?
As four new chemical elements are named, here's all you need to know.