How does nuclear fusion provide significantly large amounts of energy when the atoms are so tiny ?

Question: How does nuclear fusion provide significantly large amounts of energy when the atoms are so tiny ?
- Keywords:
  atoms,
  energy,
  nuclear fusion
Asked by anon-240738 to Rebecca on 9 Mar 2020.
- Rebecca Wong answered on 9 Mar 2020:
  
  It is pretty mind boggling to be honest!
  
  It is all about the relationship between the different forces in the atoms. Inside the nucleus there are protons (positively charged) which repel each other because of the ‘Coulomb force’. You can think of it a bit like the North poles on two magnets repelling each other. There is also the ‘strong nuclear force’ which overcomes the Coulomb force at very short range (i.e. very small nuclei), meaning that protons do actually stick together sometimes. The strong nuclear force also causes the neutrons to stick together with the protons in a nucleus. So when small nuclei are fused together this produces a lot of energy because of the net attraction from the strong nuclear force, pulling together their neutrons and protons.

Question: How does nuclear fusion provide significantly large amounts of energy when the atoms are so tiny ?