From the breath you take to the ground you walk on and most things in between, they’re all made of molecules. That’s true of both living and non-living objects. You can’t see molecules with the naked eye but if you could take a closer look, at say a glass of water, you’d find its molecules were made of even smaller building blocks called atoms – a single molecule is therefore a group of atoms bound together.
There are over 100 different kinds of atoms, one for each element on Earth, from gases like oxygen and nitrogen to solids like iron and gold. Each of these different atoms has unique characteristics.
Getting back to those water molecules, they’re made up of two hydrogen atoms and an oxygen atom. Like any recipe, if you change the amounts of each ingredient, you get a different product. So, combine two hydrogen atoms and two oxygen atoms and you get hydrogen peroxide – often used as bleach and not something you’d want to drink!
So why is it that groups of atoms stick together to form molecules in the first place? That comes down to what the atoms are made up of – unsurprisingly, even smaller particles! Some of these tiny particles are called electrons and when atoms come together to form molecules they share these electrons around, which acts like glue holding the different atoms together.
With so many different atoms to play with, the possibilities are endless. At the simpler end of things is water made of just three atoms, while haemoglobin in our red blood cells is made up of thousands of carbon and hydrogen atoms, hundreds of oxygen and nitrogen atoms, as well as sulphur and iron.