8a Solubility and particle size To show that small particles dissolve faster than the large particles add 4 g of coarse able salt to one testtube half filled with water and 4 g of fine table salt to a second testtube containing the same amount of water or use whole and crushed copper sulphate crystals Stir or shake both tubes equally and simultaneously Pause after every few seconds to observe the amount of undissolved salt left in each tube