Thermite

The thermite reaction produces molten iron by reducing iron(III) oxide with aluminum powder. Once ignited, the highly exothermic reaction releases intense heat and light, creating a dramatic classroom demonstration of redox chemistry.

1. Fill a metal bucket halfway with sand and create a small depression in the center to capture molten iron.
2. Place a flower pot in a ring stand directly over the bucket. Cover the hole in the pot with filter paper.
3. Add about ½ inch of thermite mixture (iron oxide and aluminum powder) into the pot.
4. Sprinkle a thin layer of red thermite starter powder on top of the main thermite charge.
5. Insert a strip of magnesium ribbon into the thermite mixture, leaving part exposed.
6. Ignite the magnesium ribbon with a Bunsen burner flame. Step back as the thermite ignites.
7. Observe as the reaction produces molten iron and aluminum oxide with a brilliant light.
8. Once cooled, lift the solidified iron from the sand using tongs.

Thermite reaction, step by step - Any Excuse for a Chemistry Experiment:

Thermite Reaction Demo - osuchemistry:

📄 Thermite - University of Washington: https://chem.washington.edu/lecture-demos/thermite

• Demonstrate different oxide reactants (e.g., copper(II) oxide or manganese dioxide) to show other thermite reactions.
• Use small quantities to safely illustrate the principle without excessive heat.
• Compare ignition methods - magnesium ribbon fuse vs. pre-lit magnesium dropped into the mixture.

• Perform only in a controlled laboratory or outdoor environment.
• Molten iron is extremely hot—never attempt to contain it with water or glass.
• Use a bucket of sand as the only safe catch material.
• Keep all flammable materials (paper, backpacks, screens) far away.
• Everyone must wear safety goggles, heat-resistant gloves, and stand well back.
• Do not scale up the reaction; excessive amounts are very dangerous.
• Only experienced instructors or demonstration technicians should perform this experiment.

• Why does aluminum reduce iron oxide so effectively? (Aluminum has a stronger affinity for oxygen than iron, driving the redox reaction.)
• What are the products of the thermite reaction? (Molten iron metal and aluminum oxide.)
• Why is magnesium ribbon used as a starter? (Its high ignition temperature and strong flame can initiate the thermite reaction, which otherwise requires very high heat to start.)
• Why is water never used to contain the molten thermite? (Water reacts violently with molten metal, producing steam explosions.)
• What real-world applications use thermite reactions? (Railroad track welding, military incendiaries, and metal cutting in demolition work.)