1) Take three test tubes and place clean iron nails in each of them.
2) Label these test tubes A, B and C. Pour some water in test tube A and cork it.
3) Pour boiled distilled water in test tube B and add about 1 ml of oil and cork it. The oil will flow on water and prevent the air from dissolving in the water.
4) Put some anhydrous calcium chloride in test tube C and cork it. Anhydrous calcium chloride will absorb the moisture from the air.
5) Leave all these test tubes for a few days and then observe them.
6) You will observe that iron nails in test tube A’ get rusted. But they do not rusted in test tubes B' and C.
7) In the test tube A' the nails are exposed to both air and water. In the test tube 'B' the nails are exposed to only water and the nails in test tube 'C' are exposed to dry air only.
8) From this activity we conclude that both air and water are necessary for corrosion (Rusting) or iron.