How does stuff cool? Part I - Convection

1. How does stuff cool?Part I - Convection KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram.

2. Starter • 4 possible starters. Choose as appropriate:- • Convection Current Bunsen burner • Flying Tea Bags. • Hot air balloon. KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram.

3. Convection Current of a Bunsen burner • DEMO:- Carefully bring your hands closer to the flame. What do you notice? • Place the Bunsen burner underneath the IWB or about a meter away from a OHP and observe carefully. Ask the students to explain what is going on. KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram.

4. Flying Tea Bag Demo • Observe what happens here. • Can you explain why this happens? KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram.

5. Can you explain how Chinese Lanterns work? KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram.

6. Can you explain how a hot air balloon works? KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram.

7. Lesson Title: Convection

8. Keywords: • Create sentences that correctly use the keywords below. • insulation, conduction, convection, radiation, pockets of air. Put your hand up if there is any key word from the list that you don’t know the meaning of.

9. Learning Activities for Outcome 1

10. How does it work? The demo works due to Convection. Convection is a method of heat transfer which occurs mainly in fluids (Liquids and Gases). It depends on the fact that hot gases and liquids are always less dense than cold gases and liquids. • KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram.

11. Demo / Class experiment of hot water and cold water What do you notice? • KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram.

12. Demo / Class experiment of hot water and cold water What do you notice? Hot water is less dense than cold water. Hot water rises and cold water sinks. • KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram.

13. Keywords: Create Evaluate Analyse Apply Understand Remember Demonstrate your Learning for Outcome 1 Create (A*) Combine construct Develop Imagine Design Change Improve Discuss Create Invent Suppose Put together Make up Synthesise Evaluate (A) Judge Justify Defend Decide Agree Value Prove Check Criticise Recommend Support Test Analyse (B) Take apart Compare Classify Examine List Distinguish Simplify Theme Conclude Motive Discover Apply (C) Use Build Execute Develop Construct Identify Plan Select Solve Organise Apply Model Understand (D) Explain what when where how Rephrase Demonstrate Summarise Contrast Show Predict Compare Clarify Illustrate Categorise Remember (E) Who What When Where Why Which How Match Define List Choose Name Spell Tell Describe

14. Learning Outcome 1: Review Go back to your Learning Outcome grid and fill out the ‘How I did’ and the ‘Targets’ column.

15. Learning Activities for Outcome 2

16. Convection Current Practical • KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram. Carry out the Potassium Permanganate Experiment. Can you explain what is going on?

17. Convection Current Demo

18. KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram.

19. The experiment also works with cold water. • KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram. Place the coloured ice cube in a hot beaker of hot water.

20. Water movement Cools at the surface Convection current Hot water rises Cooler water sinks

21. Convection Warm air rises because the particles spread out. As it rises it cools down. The cool air sinks because the particles are close together. This type of heat transfer is CONVECTION

22. Keywords: Create Evaluate Analyse Apply Understand Remember Demonstrate your Learning for Outcome 2 Create (A*) Combine construct Develop Imagine Design Change Improve Discuss Create Invent Suppose Put together Make up Synthesise Evaluate (A) Judge Justify Defend Decide Agree Value Prove Check Criticise Recommend Support Test Analyse (B) Take apart Compare Classify Examine List Distinguish Simplify Theme Conclude Motive Discover Apply (C) Use Build Execute Develop Construct Identify Plan Select Solve Organise Apply Model Understand (D) Explain what when where how Rephrase Demonstrate Summarise Contrast Show Predict Compare Clarify Illustrate Categorise Remember (E) Who What When Where Why Which How Match Define List Choose Name Spell Tell Describe

23. Learning Outcome 2: Review Go back to your Learning Outcome grid and fill out the ‘How I did’ and the ‘Targets’ column.

24. New Information for Learning Outcome 3 • Visual: • Audio: • Kinaesthetic:

25. How does a fridge work? • KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram.

26. Cold air sinks Where is the freezer compartment put in a fridge? Freezer compartment It is warmer at the bottom, so this warmer air rises and a convection current is set up. It is put at the top, because cool air sinks, so it cools the food on the way down.

27. Heat losses by Convection • KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram. Think about heat being lost from a house. How could you prevent this heat from escaping? Discuss with the person next to you.

28. What is a Convection Current A phenomenon in fluids Instead of having energy moved by successive collisions of atoms and molecules, the fluid itself is set into motion called a convection current. These moving fluid currents are convection

29. How does a radiator heat the house without using a fan to spread the heat? • KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram.

30. Convection When the radiator heats the air, it becomes less dense and rises Cool air moves in to replace the air that rose This generates the air flow So radiators don’t need a fan to stir the air and to distribute heat throughout a room The rising air cools until its density matches that of the surrounding air

31. Convection Can you explain why a breeze comes from the ocean in the day and from the land at night?

32. Keywords: Create Evaluate Analyse Apply Understand Remember Demonstrate your Learning for Outcome 3 Create (A*) Combine construct Develop Imagine Design Change Improve Discuss Create Invent Suppose Put together Make up Synthesise Evaluate (A) Judge Justify Defend Decide Agree Value Prove Check Criticise Recommend Support Test Analyse (B) Take apart Compare Classify Examine List Distinguish Simplify Theme Conclude Motive Discover Apply (C) Use Build Execute Develop Construct Identify Plan Select Solve Organise Apply Model Understand (D) Explain what when where how Rephrase Demonstrate Summarise Contrast Show Predict Compare Clarify Illustrate Categorise Remember (E) Who What When Where Why Which How Match Define List Choose Name Spell Tell Describe

33. Learning Outcome 3: Review Go back to your Learning Outcome grid and fill out the ‘How I did’ and the ‘Targets’ column.

34. Review for Remembering • Stand up if you have met all three lesson outcomes? • If not what do you need to do next in order to meet the outcome? Record this in your diary as part of your homework. • Is there any part of the lesson you think you need to go over again next lesson? • Tell the person next to you three things you have learnt this lesson. • How will you remember this for your exam?

35. Plenary • Can you explain how a hot air balloon works? KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram.