If atoms are mostly empty space, why don’t we fall through the floor?
The atoms that make everything in the universe, including this screen you’re looking at right now, are mostly empty space.
Think of an atom as a nucleus surrounded by an electron. So the entire atom is the nucleus in the middle, with the electron somewhere around it. The nucleus is about a thousand million million times smaller than the entire atom. To put it another way, if the nucleus was a fly, the outer region of the atom would be about the size of a football pitch. So, about 98% of the entire atom, is empty space.
When you consider that everything, from stars and planets to animals and people, are made of these fundamental building blocks, one of the first thoughts that occurs to you is, why don’t we just fall through the floor? After all, the floor, and us, are around 98% empty space.
This is where we need to think about the electron a bit differently from how you’re taught about them in school. Instead of a point like particle whizzing around the nucleus like a planet orbiting the sun, you need to think of them as waves that form ‘electron clouds’ around the nucleus.
Stay with me.
The ‘outer edge’ of this cloud is the bit that is around a thousand million million times bigger than the diameter of the nucleus.
It’s the electrons in atoms that interact with electrons in other atoms. All electrons have a negative electrical charge.
So the reason we don’t fall through the floor is that the negative electric charge in the electrons around the atoms in our feet (or shoes, or fluffy pink socks), are repelled by the negative electric charge in the electrons around the atoms that make up the floor (or ground, or concrete, or embarrassingly patterned shag pile carpet).
By Graham Foster
Graham is a graphic designer with a passion for science
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