Question

Show the particles of matter are very tiny

Answer 1

Experiment..
Go to a dark room and make a little hole in upper side you will see that in the light there are seems like a many tiny particles are flow in air .

Answer 2

if you want example then it is here

The very, very small size of the particles of matter can be shown by performing the following experiment by using potassium permanganate and water. Potassium permanganate is a kind of matter. We take two or three small crystals of potassium permagnet and dissolved it in 100 ml of water in a beaker. The color of the water changes to purple and keep dissolving water then you will see that color will become light pink. In this way, we get a very dilute solution of potassium permagnet in water but the water is still coloured. This experiment shows that just 2 or 3 tiny crystals of potassium permagnet can impart colour to a large volume of water.