You will need the following materials:

* 4 clear plastic containers with lids

* 4 iron nails

* Water

* Air pump or syringe

* Oxygen tank or cylinder

Instructions:

1. Fill each of the four containers with the same amount of water.

2. Add an iron nail to each container.

3. Seal the lids of the containers tightly.

4. Use an air pump or syringe to remove all of the air (A) from one of the containers

5. Use an air pump or syringe to force oxygen( B) into another of the containers.

6. Leave the third container as it is (C). That is sealed but air was not replaced or removed.

7. Open the fourth container to the atmosphere (D) to serve as a control.

Observations:

After a few days, you will observe the following:

* The iron nail in the container without air (A) will not rust.

* The iron nail in the container with oxygen (B) will rust

* The iron nail in the container sealed but air was not replaced or removed (C) will rust slowly

* The iron nail in the container open to the atmosphere (D) will rust quickly

Conclusion:

The results of this experiment show that both air and oxygen are needed for iron to rust. In the container without air, the iron nail did not rust because there was no oxygen present. In the container with oxygen, the iron nail rusted because oxygen was present. In the container sealed but air was not replaced or removed, the iron nail rusted but the rate of rusting was slower than in the container with added oxygen. This is because the sealed container still contained about 20% oxygen. In the container open to the atmosphere ,the iron nail rusted most quickly because it was exposed to the highest level of oxygen.