It is believed that all things in the world are made of atoms. if that is true then it is also true that by studying the basic unit of an artifact, you can change the whole artifact if you are able to change its basic units.
Basically educationist reason that if A is made of of a lot 1000Bs then by knowing how to control a single B you give your self the ability to control ALL of A which is made up of Bs.
Applying the same to chemistry if the planet are made up of atoms, then by controlling an atom means you can control a planet. that's why they say you should learn chemistry