Take 5 ml of dettol in 100 ml of water.Observe the smell of solution.Now, take 10 ml of this solution and pour in 90 ml of water. After 2-3 more dilutions, it will be observed that the smell of dettol is still present in the diluted solutions.This proves that even a small quantity of dettol contains millions of tiny particles which kept on dividing themselves on each dilution.So, it can be said that particles of matter are very small in size.