# The Particle Model of Matter

The particle model explains how matter behaves by describing the arrangement and movement of tiny particles ([Details](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/36475)). By investigating solids, liquids, and gases, you can see how particle movement and spacing affect the properties of different materials ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/36473)).

## Exercises

**1. Particle Arrangement in States of Matter**

Draw a simple diagram of how particles are arranged in each state. Use dots to represent particles.

| State | Your diagram |
|---|---|
| Solid | |
| Liquid | |
| Gas | |

**2. Matching Particle Properties**

Match each description on the left to the state of matter on the right.

| Description | State |
|---|---|
| A) Particles vibrate in place, close together | 1) Gas |
| B) Particles move rapidly in all directions with large spaces between them | 2) Liquid |
| C) Particles slide past each other with spaces between them | 3) Solid |

**3. Movement and Attractive Forces**

In which state of matter are attractive forces between particles strongest? ________________

In which state of matter are attractive forces between particles weakest? ________________

Explain why attractive forces are weaker in gases than in solids.

_________________________________________________________________

_________________________________________________________________

**4. Comparing Density**

Two blocks have the same volume. Block A has a mass of 50 g. Block B has a mass of 80 g.

Which block is denser? ________________

How do you know? _________________________________________________________________

**5. Compressibility**

You squeeze a sealed syringe filled with water. The water does not compress much. You squeeze a sealed syringe filled with air. The air compresses easily.

Use the particle model to explain why air is more compressible than water.

_________________________________________________________________

_________________________________________________________________

**6. Multiple Choice: Particle Movement**

Which statement best describes why a gas spreads to fill a container?

A) Gas particles are attracted to the walls of the container.

B) Gas particles are always moving in all directions with large spaces between them.

C) Gas particles are vibrating in place and pushing outward.

D) Gas particles are sliding past each other slowly.

## Answer Key

1. Solid: dots tightly packed together (no spaces between); Liquid: dots with small spaces between them; Gas: dots spread far apart with large spaces between them.

2. A, 3 (Solid), B, 1 (Gas), C, 2 (Liquid).

3. Strongest in solids; weakest in gases. Gases have large spaces between particles, so attractive forces cannot pull particles together as strongly as they do in solids where particles are close together.

4. Block B is denser. Block B has more mass in the same volume.

5. Air has large spaces between particles, so particles can move closer together when squeezed. Water particles are already close together with little space, so they cannot compress much.

6. B.

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*AILI homework sheet · language en · model claude-haiku-4-5-20251001 · generated 2026-09-17 · id 8d88872b-862a-4061-9032-0b8ea6999441*

### Sources

- node:n1: Matter: Understandings of the physical world are deepened by investigating matter and energy. (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/36471)
- node:n2: How can states of matter and other physical properties be explained using the particle model of matter? (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/36472)
- node:n3: Students investigate the particle model of matter in relation to the physical properties of solids, liquids, and gases. (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/36473)
- node:n4: Details (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/36475)