In science, we don't prove things

Rather, we try to prove that the opposite of our hypothesis is wrong. We try to rule out all other possibilities so that our hypothesis is the only option left. For example, let’s say that I think the refrigerator smells bad because of the old cottage cheese in there. If I take the cottage cheese out and it doesn’t smell bad anymore, I got my desired result. That does not prove that it was the cottage cheese making the fridge smell bad, but it proves that wasn’t not the old cottage cheese. If I had taken the cottage cheese out and the fridge still smelled bad, I didn’t get my desired result. This proves that my null hypothesis, that it was not the cottage cheese causing the bad smell, was correct.