I have a question regarding matter and energy. I know that matter is made of small atoms and even the littlest things have lots of atoms. But, what would happen if atoms were as big as marbles?
Imagine that you have a key in your hand. Without a doubt, it is impossible for you to see the atoms that make up this key. If you say, "I must see these atoms", then you must visualise the key to be as large as earth. If you were able to visualise the key to be as large as earth then every atom inside it would be as large as cherries and so you could see them.
By the way, good use of of the subjunctive: "were" in if atoms were.
It's an interesting question...
if atoms were actually as big as marbles, then would quantum mechanics still apply? Or would they have enough mass so that Newtonian mechanics would work. Or, if atoms were that big, then we'd all be bigger as well, nothing has really changed, has it? It's all relative, isn't it?
You touch on an interesting question. We still don't know how to relate quantum mechanics (basically, physics that "works" at the atomic level" and general relatively (physics that "works" at a larger body level) in one unified theory. This is because, among other reasons, it is difficult to experiment at an atomic level, which makes sense! But it's something scientists such as the ones at CERN are doing.