Why Iron Rusts
Class 7 Science: physical and chemical changes (rusting)
Put iron nails in three test tubes: air and water, dry air, and water with no air. Wait a few days and find out what rust needs, then protect the nails.
Words to know
- Rust
- A brown flaky coating (iron oxide) that forms on iron in moist air.
- Chemical change
- A change in which a new substance is formed, like rust from iron.
- Galvanisation
- Coating iron with a layer of zinc so it does not rust.
- Oxygen
- The gas in air that combines with iron to make rust.
- Moisture
- Water or water vapour, which rust also needs.
Quick check
Answer 3 questions to check what you learned.
Try at home
Leave one iron nail in a cup of water, one in a dry closed jar and one painted with nail polish in water. Check them every day for a week.