The problems are on the states of matter worksheet. Try them on your own first, then compare with the answers below.
Quick answer: The three states of matter are solid, liquid and gas. These worked answers correct the 20 problems of the grade 6 science worksheet on states of matter, from sorting everyday items to evaluating a human model: each solution shows the formula, the substitution and the final answer with its unit.
Check each answer against the full method. Where a problem asks you to explain, use the words particles, spaced, touching, vibrate or slide, and make sure units are written after every number.
Level: Grade 6 science (Year 7 · Class 6) · Curriculum: MS-PS1-4
Problem 1 Sorting everyday items
1. Solids: brick, pencil, coin. Liquids: orange juice, milk. Gases: helium, the air in the football.2. Solid has a fixed shape.
Problem 2 Shape and volume
1. Solid (fixed shape and fixed volume).2. Liquid (fixed volume, takes the shape of its container).
3. Gas fills the whole container.
Problem 3 Reading particle diagrams
1. A is a solid, B is a liquid, C is a gas.2. The particles of B are close together, touching, and slide past one another.
3. Box C has the particles furthest apart.
Problem 4 Pouring juice
1. 300 mL in the glass.2. 300 mL in the bowl, because liquids keep their volume.
3. Only the shape of the juice changes.
Problem 5 Cooking oil bottles
1. 1.5 L × 1000 = 1500 mL.2. 1500 mL ÷ 250 mL = 6 bottles.
3. The volume of oil stays the same; only its shape changes.
Problem 6 Describing particle motion
1. Vibrate on the spot.2. Slide past one another.
3. Fly in all directions.
Problem 7 Why a brick does not pour
1. In the brick the particles are packed in fixed positions and can only vibrate, so the brick keeps its shape.2. Water particles slide past one another, so water flows and takes the shape of any container.
Problem 8 Squeezing air in a syringe
1. 50 mL − 20 mL = 30 mL.2. 20 ÷ 50 = 2/5 = 0.4 (40 %).
3. No, the number of particles is the same; they are only closer together.
Problem 9 Squeezing water in a syringe
1. The reading stays about 50 mL.2. Water particles are already touching, so there is no empty space for them to move into. A liquid cannot be compressed.
Problem 10 Pumping a bike tyre
1. 400 ÷ 100 = 4 times.2. After pushing, the particles are much closer together than before.
3. The pump contains the same number of particles.
Problem 11 A smell spreading
1. The further from the bottle, the longer the smell takes to arrive.2. 22 s − 4 s = 18 s longer.
3. Vinegar particles move and mix with the air particles (diffusion) until they reach noses.
4. In a cold room the particles move more slowly, so the times would be longer.
Problem 12 Is sand a solid?
1. Solid.2. Each grain is a small solid with fixed shape. The grains can slide over one another, so the heap flows, but the particles inside each grain stay fixed.
Problem 13 Spot the errors
1. Solid particles do move: they vibrate around fixed positions.2. The weakness is the idea of “lighter”. Gas particles are far apart because they have enough energy to move freely and are not held together.
Problem 14 Same gas, two boxes
1. Box Q has the particles further apart.2. 6 L ÷ 2 L = 3 times larger.
3. The particles would be pushed closer together; the gas is compressed.
Problem 15 Why a balloon stays inflated
1. The particles move quickly and randomly in all directions.2. They keep hitting the inside of the rubber and pushing it outwards, so the balloon stays inflated.
Problem 16 Filling juice bottles
1. 99 L × 1000 = 99 000 mL.2. 99 000 ÷ 330 = 300 bottles.
3. 300 ÷ 6 = 50 cartons.
4. Liquid has a fixed volume. Air would spread out and fill any container, so its volume depends on the container.
Problem 17 Flowing sand timer
1. 120 g ÷ 240 s = 0.5 g/s.2. Mass gone = 0.5 × 100 = 50 g, so 120 g − 50 g = 70 g left.
3. Sand is made of tiny separate solid grains that can slide past each other and fall through the neck one by one.
Problem 18 Scuba tank
1. 1800 ÷ 12 = 150 times.2. The gaps between the particles became much smaller.
3. The number of particles did not change.
4. Water particles already touch, so there are no gaps to squeeze.
Problem 19 Design a fair comparison
1. Two identical syringes, one with air and one with water, blocked tips.2. Keep the start volume (for example 40 mL), the tip seal and the force used the same.
3. Measure the volume on the syringe scale after pushing.
4. Air volume falls a lot; water volume stays almost unchanged.
Problem 20 Evaluating a human model
1. Tight rows wobbling = solid (vibrating in fixed places); walking shoulder to shoulder = liquid; running around = gas.2. It shows how close the particles are and how they move.
3. Weakness: real particles are not people; they do not choose to move and they do not hold hands, and they are much smaller.
