Why Does Metal Rust?
Rust is the orange-brown, flaky layer that forms when iron (or steel, which is mostly iron) reacts with oxygen in the presence of water. Chemically it is iron oxide: iron atoms and oxygen atoms join together, and water speeds the reaction up by helping them meet. Rust needs all three parts of its 'recipe' β iron, oxygen and water β so removing any one of them stops it from forming.
Rust matters because it weakens metal. A rusted gate, bicycle chain, nail or railing becomes crumbly and can break, which is why rust costs people money and can be unsafe. Singapore's hot, humid weather means there is plenty of invisible water vapour in the air all day, so metal here rusts faster than in dry, cool places.
The key ideas a learner picks up are: rust is iron oxide formed from a three-ingredient recipe; water acts as a helper that speeds it up; humidity explains why some places rust faster; and rust is prevented by keeping water and air away from iron β by painting, oiling, galvanising or coating the metal.
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The mystery of rustπ©β‘οΈπ€ Why Does Metal Rust? Have you ever seen an old bicycle, a gate, or a nail turn crumbly, bumpy and orange-brown? That flaky orange stuff is called rust. Rust is what happens when iron metal slowly changes into something new. It is not painted on β the metal is turning into rust! Let's become rust detectives π and find out exactly why it happens.
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The rust recipeRust needs a recipe π³ Just like a cake needs ingredients, rust needs three things to form. Drag each ingredient into the bowl to mix the rust recipe! π©Iron π§Water π¬οΈAir(oxygen) Β· Β· Β· Drop here Tip: you can also tap an ingredient to add it.
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Iron meets oxygenWhat actually happens? βοΈ Tiny pieces of iron and tiny pieces of oxygen from the air join together. Water helps them meet much faster. When they join, they make a brand-new orange material β rust! Fe οΌ Oβ Mix them! π₯ Press the button to see iron and oxygen join. Scientists call rust iron oxide β that just means "iron joined with oxygen".
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Test the recipeTry the experiment π§ͺ If rust needs water AND air, what if we take one away? Tap the buttons under each jar to turn water and air on or off, then watch the nail. π© π§ Water π¬οΈ Air π© π§ Water π¬οΈ Air Goal: make a nail go rusty! Which combination works?
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Why Singapore rusts fastSingapore loves to rust πΈπ¬π΄ Singapore is hot and very humid β that means lots of invisible water floating in the air all day. More water in the air means metal rusts faster! Tap each clue to see why metal rusts quickly here: π«οΈ Humid air everywhere β tap me π Sea all around us β tap me π§οΈ Frequent rain β tap me You've revealed 0 of 3 clues.
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How to stop rustHow do we stop rust? π‘οΈ To stop rust, we must keep water and air away from the iron. Tap the 3 ways that protect metal from rust! π¨Paint it π¦Splash water on it π’οΈAdd oil/grease βοΈLeave it in the rain π Keep it dry indoors Found 0 of 3 good protectors.
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You're a rust detective!ππ¬ Brilliant work, detective! You cracked the mystery of rust. Here's what you discovered: π© Rust happens when iron turns orange and crumbly. π³ The rust recipe needs iron + water + air (oxygen) β all three. βοΈ Iron joins with oxygen to make a new material called iron oxide. πΈπ¬ Singapore's humid, salty air makes metal rust faster. π‘οΈ We stop rust by keeping water and air away β paint, oil, or stay dry. Next time you spot something orange and flaky, you'll know exactly why β well done! π
Frequently asked questions
- What is rust made of?
- Rust is iron oxide β a compound formed when iron joins with oxygen from the air. Water helps the two meet faster, which is why damp metal rusts more quickly.
- What three things does metal need to rust?
- Iron, oxygen and water. If any one of these is missing, rust cannot form, which is why dry or sealed iron stays shiny for much longer.
- Why does metal rust faster in Singapore?
- Singapore is hot and very humid, so there is a lot of invisible water vapour in the air all day. More water in the air means iron reacts with oxygen faster and rusts sooner.
- How can we stop metal from rusting?
- Keep water and air away from the iron. Painting, oiling or greasing, galvanising (coating with zinc) and keeping metal dry all block the rust recipe from working.
- Does all metal rust?
- No β only iron and steel rust, because rust is specifically iron oxide. Metals like aluminium, copper and gold do not rust, though some can corrode or tarnish in other ways.
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