Burning Steel Wool Increases Its Mass

When steel wool is ignited, it reacts with oxygen in the air to form iron oxide. Surprisingly, the mass of the steel wool increases after burning because oxygen atoms from the air combine with the iron atoms.

1. Weigh a piece steel wool before burning and record its mass.
2. Place a heat-resistant surface or in a fire-safe container.
3. Ignite the steel wool using a flame or a battery (steel wool ignites easily when touched to both terminals of a 9V battery).
4. Allow the steel wool to burn completely, observing the sparks and glowing effect.
5. After it has cooled, reweigh the steel wool and compare the mass to the original measurement.

Burning steel wool increases it's mass - DonoChem:

📄 Burning Steel Wool - The Wonder of Science: https://thewonderofscience.com/phenomenon/2018/7/8/burning-steel-wool

• Try using different grades or thicknesses of steel wool to see if the reaction is more vigorous.
• Compare the combustion of steel wool with the rusting of iron over time to link rapid and slow oxidation.

• Safety glasses required.
• Perform in a well-ventilated area away from flammable materials.
• Use tongs or tweezers to handle steel wool to avoid burns.
• Allow burned steel wool to cool fully before touching or weighing.

• Why does the mass of the steel wool increase after burning? (Because oxygen from the air combines with the iron to form iron oxide, adding mass.)
• Why might students predict a decrease in mass before the demonstration? (They may think mass is lost as smoke or fire, rather than gained from oxygen.)
• How is burning steel wool similar to rusting? (Both involve oxidation of iron, but rusting is a slower process.)
• What does this experiment demonstrate about the conservation of mass? (That mass is not lost during chemical reactions; it is redistributed and can increase when atoms from the air combine with the reactant.)