Science · Topic 67 of 124
Thermal Expansion
⭐ MasteredWhen things get hotter, their particles move faster and spread out, so most materials get slightly bigger. When they cool down, they shrink.
💡 Fun fact
Bridges have small gaps in them so they can expand on hot days without cracking.
All about Thermal Expansion
Thermal expansion means that most materials get slightly bigger when they are heated. When a material warms up, its particles move faster and push further apart. When it cools down, the particles slow down and the material shrinks again.
Engineers must allow for thermal expansion when they build things. Bridges and railway tracks have small gaps so they can grow on hot days without cracking. Glass jars can also crack if they are heated too quickly, because the outside expands before the inside.
🎮 Try it yourself!
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