How to Test for Oxygen Gas in a Test Tube

You can test for oxygen in a test tube.

Oxygen gas is all around us, and without it, we would not be able to survive. Although oxygen is clear and we cannot see it, there is a way to test for it and prove its existence. Using the principle of oxidation, or rusting steel, it is a scientific fact that it takes both oxygen and water to make steel or iron rust. With that in mind, you can set up a simple test for oxygen in a test tube.

Things You'll Need

• Fine steel wool grade 00
• Test tube
• Glass of water
• Test tube ring stand and clamp (available at science or hobby shops)
• Pencil or pen

Instructions

1. Fill a glass of water approximately three-quarters full.

2. Tear off a small piece of steel wool and roll it up in your fingers into an approximately 1-inch-diameter ball. Push it all the way down in your test tube; use a pencil or pen to get it all the way to the bottom.

3. Invert the test tube with the steel wool inside and put the open end into the water a short distance. Secure the test tube in this position by clamping it to the ring stand.

4. Allow the test tube to remain in this position, with opening submerged, for one week.

5. Remove the test tube from the clamp and observe how the steel wool looks. It will have rusted slightly by this time, proving that along with the water vapor from the glass of water, oxygen was present in the test tube to create the catalyst for the oxidation on the steel wool.

References

• Science Buddies: From Gas to Rust: Measuring the Oxygen Content of Air