A particle physicist explains just what this keystone theory includes. After 50 years, it's the best we've got to answer what everything in the universe is made of and how it all holds together.
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.