Year 8 Science · Unit 3 · Lesson 5
Foundation Worksheet
Learning Goals
Fill the gap — unit review
Choose the correct word from the word bank to complete each sentence. Two words will not be used.
All matter is explained using the model, which describes how tiny moving pieces make up every substance. A change alters the shape or state of a substance without making anything new — it is usually . A change forms new substances; the starting materials are called s and what they become are called s. When a reaction releases heat it is ; when it absorbs heat it is . A solid that suddenly forms in a liquid during a reaction is called a . Particles in a gas have high energy, which is why gases spread out and fill any container.
Odd one out — cross-lesson review
Circle the item that does not belong in each group. Then write which lesson the concept comes from (L1, L2, L3, or L4) and explain your reasoning.
| # | Group | Odd one + lesson + reason |
|---|---|---|
| 1 | Melting Dissolving Evaporating Burning | |
| 2 | Colour change Precipitate Gas produced State change | |
| 3 | Particles vibrate in fixed positions Particles slide past each other Particles move freely in all directions Particles break apart into new atoms | |
| 4 | Colour change Gas produced Precipitate formed Change of state (melting) |
1. Explain in your own words why the particle model is useful for understanding both physical and chemical changes. Give one example of each type.
2. A scientist observes a reaction producing bubbles, a colour change, and a temperature rise. Name each type of evidence and explain why they need all three observations before concluding a chemical reaction has occurred.
Wrap Up
In one sentence, what was the main idea of this unit?