What kind of evidence would convince you that all matter is really made up of collections of tiny particles?

The evidence I would use to sustaing that all matter is made up from tiny particles and we can prove it by using visual devices like microscopes to see it by ourselves.

Explanation:

The evidence that would sustain this thesis is that we as organisms are formed by different systems of living organs that at their time they are conformed by tissues made by living cells, that at their time they are made up by different organelles and that those are made of substances, that at their that these substances are made by molecules and those molecules by elements. Therefore, as we are composed of these molecules and elements, all the objects are made of them. And that we can observe all of those with different visual devices such as electric microscopes and others.