c Diffusion of liquids i Place a crystal of potassium dichromate potassium dichromate VI or ammonium dichromate at the bottom of a beaker of water To do this put a glass tube into the beaker of water so that it touches the bottom then to drop the crystal down the tube Close the top of the tube with your finger and remove the tube gently leaving the crystal in the beaker The colour of the dissolving crystal will spread throughout the water in quite a short time ii Fill a very small open bottle with a strong solution of potassium permanganate potassium manganate VII Place this in a larger jar Fill the larger jar very carefully by pouring water down the side until the water level is above the top of the small bottle Leave this for a few days The potassium permanganate solution diffuses evenly through the water