No. 3: The Science Of Ant-Man
As previously mentioned, the original Ant-Man discovered microscopic particles known as Pym Particles.
But what are Pym Particles?
These particles are what every Ant-Man uses to shrink down to the size of an insect. There are some interesting facts about these particles that not many people know.

Firstly, when Ant-Man shrinks using the particles, they stunt or push the matter into the Kosmos Dimension. This basically means that Ant-Man, or anyone else using the particles, has his matter stored slowly - or "drained" if you will - into a different dimension, which is why he shrinks. When the opposite occurs and Ant-Man uses the particles to grow in size, matter is temporarily taken from this dimension in order to make the subject grow bigger. Pym Particles were originally used to be in liquid form, until Hank Pym synthesized the particles into a gas, which would be used to shrink anyone who inhaled it.
After long-term exposure to the Pym Particles, a person's body can actually start producing Pym Particles naturally in the blood. Hank Pym, Janet Van Dyne and Cassie Lang (Daughter of Scott Lang) are all characters who have this ability. The only negative side effect of over-exposure to the Pym Particles is the large physical strain that it can put on a person's body, Hank Pym himself has suffered many breakdowns because of over-using Pym Particles.
Bonus Fact: Scientist Reed Richards claims to know more about Pym Particles than Hank Pym himself, despite Pym being the one to discover them.