Q What does this picture show and who is in the best position?

1. Q What does this picture show and who is in the best position?

2. To describe the process of convection in terms of particle movement. To explain why convection cannot happen in solids but does in liquids and gases. To give examples of where convection currents occur. click here

3. Convection currents • Fluids ( ______ and ___) are poor _______, which is why ________ materials contain pockets of trapped air and other fluids can transfer ____ if they are free to ___. Words – conductors, energy, insulating, move, gases, liquids.

4. heat heat Convection currents The movement of hotter areas in a liquid can be seen using potassium permanganate as a dye: This cycle is called aconvection current. Can you explain how the convection current moves using the idea of density?

5. heat The heated fluid particles gain energy, so they move about more and spread out. The same number of particles now take up more space, so the fluid has become less dense. What are the Keywords? Liquids and gases can both flow and behave in similar ways, so they are called fluids. What happens to the particles in a fluid when it is heated? less dense fluid

6. Convection in Liquids Warmer regions of a fluid are more dense than cooler regions of the same fluid. The warmer regions will rise because they are more dense. The cooler regions will sink as they are less dense. This is how heat transfer takes place in fluids and is called convection. The steady flow between the warm and cool sections of a fluid, such as air or water, is called a convection current.

7. Convection in Liquids • Click here Convection is the transfer of heat energy by the movement of matter."

8. Using Convection Q) Why is the freezer compartment at the top of a fridge? The freezer compartment is at the top of a fridge because cool air sinks. The freezer cools the air at the top and this cold air cools the food on the way down. It is warmer at the bottom of the fridge. This warmer air rises and so a convection current is set up inside the fridge, which helps to keep the fridge cool.

9. Describe what is happening in these diagrams

14. Convection What are the Keywords? Convection occurs in liquids and gases. This is when heated stuff moves in bulk to a cooler region and takes the heat with it. The movement creates a convection current. Currents are created as fluids rise when they are heated (they become less dense – particles are more spread out). They then fall when they cool down (they become more dense – particles are closer together).

15. Questions • click here • What is convection? Explain in as much detail as you can. • Why doesn’t convection happen in solids? • If the heating is turned off on a day in winter, why is the coldest place in the room under a window? • Explain why smoke detectors are usually fitted to ceilings rather than walls? • A* Write a marketing brochure for a conservatory to explain how opening a roof vent near the top can help to cool the whole space. Use ideas from lesson 1.1, 1.3 to help.

16. If I am the answer, what is the Q?