Assignment 5
1. Conduction, convention or radiation?
| A hot air balloon rises into the air | |
| Laying on the beach I feel heat energy from the Sun | |
| A cup of tea feels hot in my hands | |
| The heating element in a kettle is at the bottom | |
| Making toast by putting it under the grill | |
| The middle of a potato baking in the oven gets hot after the outside | |
| Chips in the canteen are kept warm with a heat lamp | |
| I hold a metal rod in a Bunsen flame. After a few minutes I have to let go. | |
| The rooms upstairs are always warmer than downstairs |
2. Fill in the missing words
Heat energy flows from _________ to ___________ temperatures. (unless we do work to make it go the other way)
Conduction is the flow of heat through _______________ . Metals such as __________ are good _____________ of heat, non- metals such as ____________ are usually good _____________.
Gases and __________ are very poor conductors (especially still ______ ). Heat energy in these travels by ______________. This is when hot regions in the gas rise and cold regions sink. The gas may end up travelling in circles called _________________ __________________.
Heat radiation is also called _________ _______ radiation. It is invisible but if it is strong enough we can ______ it. It can travel through a vacuum (we get lots from the _____).
Objects which are __________ than their surroundings emit heat radiation.
Objects which are colder than their surroundings _________ heat radiation.
3. List at least 7 ways that we might stop heat energy escaping from our homes.
4. What does a thermostat do?