ACT Preparation / Unit 22 ACT 2112 short lesson, about 20 seconds
States of Matter and Phase Changes
Captions available
The idea
Matter is commonly solid, liquid or gas: a solid keeps its shape, a liquid takes its container's shape, and a gas fills its container. Phase changes move matter between states.
In practice
Ice melting into water and water boiling into steam are physical changes, not chemical ones.
Where people slip
A phase change alters the state, not the substance: water is still water.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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