Before 1600, people studied substances to figure out how to do things such as turn lead into gold, but no one managed to do that. This was called alchemy. Alchemists separated the air into many parts and isolated the
noble gases from it. They also processed special minerals from a mine in
Sweden to get
rare earth metals.
Radioactivity was also discovered. Today chemists have discovered 118 different elements. Some are very common, like
oxygen. Many are very rare and expensive, like
platinum. Some cannot be found on earth and can only be made in labs, like
Since the 1920s, the increased understanding of
physics has changed chemists'
chemical reactions. With smaller and faster
computers, chemists have built better tools for
analyzing substances. These tools have been sent to study chemicals on
Mars. Police also use those tools to study