Thermal Expansion
Thermal expansion explained in an easy to understand way:
Imagine trying to squeeze into your favorite pair of jeans after a big holiday meal. Just like how your jeans feel tighter when you're full, materials expand when they heat up. In both cases, whether it's your waistband or a metal rod, adding energy (from food or heat) causes an increase in size, as molecules move apart to make room, making it a perfect analogy for thermal expansion.
Practice Version
Thermal Expansion: An increase in the size of a substance when it is heated. Thermal expansion. When most materials are heated, their particles move faster and spread apart slightly, causing the material to expand.