Quick answer: The particle model says that all matter is made of tiny particles that are always moving. This grade 7 science test on particle model has 8 questions worth 20 marks, to do in 45 minutes: three states, reading the diagram and pressure of a gas. The mark scheme is on a separate page; free printable PDF.
This test has 8 questions and is worth 20 marks. Answer in full sentences when a question says explain, and show working in every calculation. Use only your own knowledge of the particle model and give units.
Level: Grade 7 science (Year 8 · Class 7) · Curriculum: MS-PS1-1, MS-PS1-4
Question 1 Three states (2 marks)
Name the state of matter described by:- particles touching, in fixed positions, only vibrating (1 mark)
- particles far apart, moving fast and freely (1 mark)
Question 2 Reading the diagram (3 marks)
Look at the diagram.- Identify which box shows a solid. (1 mark)
- Describe how the particles in box Q move. (1 mark)
- Explain why box Q could be squashed into a smaller volume but box P could not. (1 mark)
Question 3 Pressure of a gas (2 marks)
A sealed bottle of air is left in the sun. Explain, using particles, why the bottle gets harder to squeeze.Question 4 Diffusion (3 marks)
A cook in Lahore fries spices in the kitchen.- Name the process by which the smell reaches the garden. (1 mark)
- Explain how this process happens. (2 marks)
Question 5 Spreading speed (3 marks)
Ink spreads 4.5 cm in 90 s in a cup of warm water.- Calculate the average speed in cm/s. (2 marks)
- State what happens to the speed if the water is cooler. (1 mark)
Question 6 Changes of state (2 marks)
Name the change of state in each case.- Solid to liquid (1 mark)
- Gas to liquid (1 mark)
Question 7 Plateau on a graph (3 marks)
When a solid is heated, its temperature stops rising at the melting point for a while. Explain why, using the particle model.Question 8 Spot the mistake (2 marks)
Wanjiru says: ‘When water boils, the water particles get bigger and turn into steam particles.’ Identify the mistake and correct it.
