Year 7 - Science
Mixing substances of different temperatures
Heating and cooling
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
This unit explains energy transfer between objects due to temperature differences, through conduction or radiation, the role of insulators, and thermal equilibrium. It covers particle arrangements and motions in solids, liquids, and gases and Brownian motion.
Lesson Summary
You will learn to predict the resulting temperature when two substances of different temperatures are put together.
Key Notes
- Mixing hot water with cold water results in water cooler than the hot water and warmer than the cold.
- When hot and cold water are mixed, the temperature is closer to that of the water there was more of.
- A cold object placed in hot water makes the water particles move more slowly and those in the object move more quickly.
- A hot object placed in cold water makes the water particles move more quickly and those in the object move more slowly.
Vocabulary To Learn
- volume: the amount of space an object takes up
- particle model: the idea that all objects are made of tiny particles that are in constant motion
- temperature: the higher the temperature of an object, the faster its particles move and the hotter it is
- collide: when two objects bump into each other
Common Mistakes To Avoid
- When samples of water are added at different temperatures, some pupils add or subtract the temperatures, applying a mathematical process without appearing to think about what is happening.
3 Quick Questions (With Answers)
1. Explain the scientific idea in this lesson using two key points.
Mixing hot water with cold water results in water cooler than the hot water and warmer than the cold. When hot and cold water are mixed, the temperature is closer to that of the water there was more of.
2. Define this scientific word and use it in context. 'volume'
the amount of space an object takes up. Include the word in a full scientific explanation, not as a single label.
3. Correct this common scientific misunderstanding.
Mistake: When samples of water are added at different temperatures, some pupils add or subtract the temperatures, applying a mathematical process without appearing to think about what is happening. Correction: Ask pupils to predict changes to the resulting temperature using water at a range of starting temperatures and then demonstrate each one, measuring the temperature of the resultant mixture each time.
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