Lesson 4 of 10
Three arrangements
Show on a big screenA steel tumbler keeps its shape. Water in it takes its shape. Air fills it. All three are made of particles.
Step 1 of 4
- Solid: particles are packed tight. They only vibrate, shaking in place.
- Liquid: particles stay close but slide past each other.
- Gas: particles move freely, far apart.
- Same kinds of pieces, three arrangements.
New word
- Interparticle attraction — the pull that holds particles together.
The rule
In a solid, particles are packed close and held by strong pulls. In a liquid, they slide past each other. In a gas, they move freely in every direction.
Strong pulls hold a solid's particles in place. So a solid keeps its shape. Gas particles feel almost no pull. So a gas spreads to fill its container.
Volume is the space a thing takes up.
| State | Shape | Volume | Particles |
|---|---|---|---|
| Solid | Fixed | Fixed | Very close, strong pull, only vibrate |
| Liquid | Not fixed | Fixed | Close, weaker pull, slide past |
| Gas | Not fixed | Not fixed | Far apart, almost no pull, move freely |
Liquids and gases flow. They are called fluids.
Watch out!
Sand pours, but each grain keeps its shape. So sand is a solid.
Ask what each thing is.
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Try the lab to finish this lesson.