Solids, liquids and gases: what children learn
This game asks whether a material is a solid, a liquid or a gas at room temperature, or which of four materials is in a given state. The tricky ones are deliberate. Sand and flour can be poured, but each grain is a tiny solid. Honey is thick, but it flows, so it is a liquid. Air, oxygen, helium and carbon dioxide are all gases, even though we cannot see them. Water appears three times, as ice, water and water vapour, because the same material can change state.
Suggested grade 3 practice, selected by skill and reading demand. US states and schools teach these topics in different grades; this is not a state-standards alignment claim.
Next Generation Science Standards teaching connection: PS1.A: states and properties of matter. Sorting solid, liquid and gas examples builds vocabulary around matter. The linked Grade 2 expectation concerns investigating observable properties; this game includes additional gas vocabulary and does not assess that investigation. Read the framework.
How to play
Sort the cards into the right groups. Tap a card, then its group. You can also drag a card, or press the number on its group. Each game has 3 rounds with no timer. Every card is checked as soon as you place it: a card in the wrong group comes back with a hint, and you get a point for each card you place right first time. For a quicker go, choose Quick quiz: 10 multiple-choice questions in 120 seconds (choose Relaxed for more time).
Step by step
- Can you hold it in a pile?. If it keeps its own shape, it is a solid. Grains such as sand, sugar and flour are solids too.
- Does it flow and make a puddle?. If it pours and spreads into a flat pool, it is a liquid, even if it is thick like honey.
- Does it spread out to fill the space?. Gases have no shape of their own. They fill a balloon or a room, and you usually cannot see them.
- Check the temperature. The game means room temperature. Chocolate is a solid in the cupboard but melts into a liquid when warm.
- Remember water changes state. Ice (solid) melts into water (liquid), which evaporates into water vapour (gas).
Worked examples
Example 1: At room temperature, is sand a solid, a liquid or a gas?
Working: Sand pours, but look closely: each grain keeps its own shape and you can pile it up.
Answer: A solid.
Example 2: Which of these is a gas at room temperature: honey, flour, helium or a stone?
Working: Honey flows (liquid), flour and a stone keep their shape (solids). Helium fills balloons.
Answer: Helium.
Example 3: Is honey a liquid or a solid?
Working: Honey is thick, but it flows and takes the shape of its jar.
Answer: A liquid.
Common mistakes and how to fix them
- Thinking anything that pours is a liquid. Pour sand and water onto a tray. Sand makes a pile; water makes a flat puddle.
- Thinking thick means solid. Tip a jar of honey slowly. It flows, so it is a liquid.
- Thinking gases are "nothing". Blow up a balloon and squash it gently. Something is inside pushing back: air, a mixture of gases.
- Calling water vapour a different material from water. It is the same material in a different state. Watch a cold window steam up as vapour turns back into liquid.
Activities to try at home
- Make a states-of-matter hunt in the kitchen: find five solids, five liquids and one gas (the bubbles in a fizzy drink).
- Freeze some juice into lollies and watch them melt again. Talk about solid and liquid.
- Pour sand, rice and water into different containers and compare what happens.
- Print the worksheet and ask your child to explain the tricky ones (sand, honey, air).
Ideas for the classroom
- Set up a carousel of materials in sealed containers (sand, honey, oil, air in a syringe, rice, ice) and ask groups to sort them.
- Act out particles: students pack tightly (solid), move around each other (liquid) and spread across the hall (gas).
- Use a syringe to show that gases can be squashed and liquids hardly at all.
- Follow the game by exploring the water cycle, especially evaporation and condensation.
Free printable game and worksheet
The free printable starts with a game sheet, such as a color-by-answer picture, an answer maze or a secret-code joke, followed by a worksheet. Both use the same checked questions as the online game, and the answers are on the last page. Print it, or save it as a PDF from your browser’s print menu.
Open the free printable game and worksheet
Frequently asked questions
Is sand a solid or a liquid?
Sand is a solid. It can be poured, but each grain keeps its own shape and size, and sand forms a pile rather than a flat puddle.
Is fire a gas?
Flames are hot, glowing gases, but fire is not a material in the same way. It is better left for a discussion than used as a quiz question.
Why does the game say "at room temperature"?
Many materials change state when heated or cooled. Chocolate melts, water freezes. Saying room temperature keeps one right answer.