A Aim: To compare the formation of rust on iron nails placed in test tubes containing different substances over a certain period of time. Apparatus: • Test tube rack Three test tubes Stoppers Six clean iron nails Water Table salt Marking pen to label the test tubes Spoon Method: 1. Label the three test tubes A, B and C. 2. Test tube A: place two nails in the test tube, cover the nails with cool boiled water and close the test tube so that no further oxygen enters the test tube. 3. Test tube B: place two nails in the test tube, cover the nails with cool boiled water, add a teaspoon of table salt, and leave the test tube open so that oxygen may freely enter. 4. Test tube C: place two nails in the test tube and leave the test tube open so that oxygen may freely enter the test tube. 5. Leave all three test tubes for 1-2 days. 6. Observe each nail carefully. No ur 16.17 Tap water Lavet of اس Air and salt water AIT. No WHCT Sali water B C




1. write the hypothesis for this investigation ​