unit 3.3 Flashcards
1
Q
What is density?
A
How much mass is in a volume.
2
Q
How does conduction work?
A
When a solid is heated it vibrates, it then collides with nearby particles to eventually heat up the whole solid.
3
Q
Why are metals the best heat conductors?
A
Because they have free electrons.
4
Q
How does convection work?
A
- Hot fluid becomes less dense so it rises.
- The fluid then cools down and gets more dense so it falls.
5
Q
What does ‘absorb’ mean?
A
To take in
6
Q
What does ‘reflect’ mean?
A
To bounce off
7
Q
What does ‘emit’ mean?
A
To give out.
8
Q
what colour is the best emitor and absorber?
A
black
9
Q
Which colour is the best reflector?
A
Silver
10
Q
What is radiation?
A
The transfer of heat energy by waves.
11
Q
What is the equation for payback time?
A
Payback time ( years) = Cost of insulation/ Saving each year
12
Q
What is payback time?
A
How long it would take you to get your moneys worth.
13
Q
What are some factors affecting payback time?
A
- Inflation
- Weather (in warmer weather less insulation is used)
