1. ➜ HINTS Chemistry Topic 1 Particles 1.1 Particle model (page 73) 1.Re-read the bullet point lists for each state of matter at the bottom of page 72. 2.Think about what happens to the shape of an ice cube as it melts. 3.This would be particularly important in a hot country. 4.Remember, ‘compress’ means to squash or put under pressure. 5.Remember that particles are very small. Science Progress © Hodder & Stoughton 2014

2. ➜ HINTS Chemistry Topic 1 Particles 1.2 Changing state (page 75) 1.There are no arrows on the solid particles because they are only vibrating. 2.What does having energy allow particles to do? 3.Look at the data table for the melting and boiling points of water and mercury on page 75. 4.In both examples particles would gain energy, but there are different changes to be seen for each state. 5.Think about the weather conditions needed for puddles to dry up. Science Progress © Hodder & Stoughton 2014

3. ➜ HINTS Chemistry Topic 1 Particles 1.3 Diffusion and gas pressure (page 77) 1.Remember diffusion happens due to movement of particles. 2.What sort of particles are we surrounded by? 3.Make a clear key for the water and the dye particles. 4.Focus on the size of the balloon. 5.Remember, gas pressure is affected by how often the particles hit the container and how hard. Science Progress © Hodder & Stoughton 2014

4. ➜ HINTS Chemistry Topic 1 Particles 1.4 Introducing density (page 79) 1.What does ‘hard’ mean? (Look back at page 78 to find out.) 2.Read back through the information on ‘Properties of solids’ on page 78. 3.Imagine how a car would need to be changed to run on solid fuel. 4.Think about mass and volume. 5.Draw a particle diagram of the deflated and inflated rubber ring to help you see the changes. Science Progress © Hodder & Stoughton 2014

5. ➜ HINTS Chemistry Topic 1 Particles Asking questions and making predictions: Applying the particle model (pages 80-81) 1.Look at Figure 1 to help describe your observation. 2.For the shape to change, the particles need some space to move into. 3.Remember the difference between hard and strong. 4.Use Figure 3 to help you create your diagram. 5.Think about how a balloon looks after it has been blown up and deflated. 6.What happens if you pull an elastic band too far? 7.Look at the collapsing can on page 77. 8.Think about how to increase the air pressure inside the carton? 9.Think about expansion and flow. Science Progress © Hodder & Stoughton 2014