This GCSE Physics Energy quiz takes a look at heating and insulating. Energy efficiency in buildings usually involves using thermal insulation to hold in the heat. Heating and insulating buildings has become a major agenda for many mainstream politicians. This has resulted in various projects allowing home owners to obtain low cost insulation as the government recognises that not only will this help save money, but also reduce environmental emissions as less fuel needs to be burnt to heat homes. You may have heard people saying 'close that door and keep the cold out'. This is incorrect as heat only flows from higher temperatures to lower temperatures. Cold doesn't move, cold is NOT a form of energy. It would be more accurate to say '... keep the cold air out'.
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One source of heat loss from buildings is draughts. Cold air coming in from the outside needs to be heated up, otherwise the inside of the house would be at the same temperature as the outside. This uses energy from the heating system and reduces the overall efficiency of the house. As the cold air comes in, it means that warm air is also leaving the building somewhere. Some hi-tech homes are completely sealed to prevent draughts, incoming fresh air from the outside is controlled by using a ventilation system. To prevent the loss of energy to the outside, these usually include an efficient heat exchanger. This transfers the heat from the outgoing air to the air coming in so that the house does not need extra heating.
You will already have studied insulating homes at KS3; there are a lot of similarities with the KS4 work, however, new ideas such as U-values and payback time are introduced as well as revising methods of insulation. U-values are a measure of how well heat can travel through a material so lower U-values are associated with better insulators. The figure is a measure of how many watts of heat energy pass through a metre squared divided by the temperature difference between the opposite sides of the insulating material. In order to be able to compare U-values directly, the materials are measured under standard conditions with carefully controlled air humidity and wind conditions.
You will have met many different types of insulation but the thing that most have in common is that they contain trapped gases, usually air. This is because gases are very poor conductors of heat. When they are trapped, it prevents them from transferring heat by convection. Most heat leaves a building by being conducted through the solids used to construct it. Some heat leaves by convection (draughts) and a small proportion leaves by radiation - all objects above absolute zero emit (give off) infra-red (heat) radiation.
The largest heat loss is through the walls and the roof as these form the largest area of a building. These are the two areas that it pays to concentrate on when planning to insulate a house. Newly built houses have insulation planned as part of the design. Older houses have solid walls and it is most efficient to insulate the outside of these, although most people choose to add insulation to the inside as it is easier and cheaper. Houses built in the second half of the twentieth century and more recently usually have cavity walls. These help to keep houses both warmer and drier with less heating than solid walled houses. Adding insulation into the cavity keeps even more of the heat in, reducing energy consumption for heating even more.
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1.
|
What do U-Values measure? |
|
[ ] |
How effective a material is as a conductor of heat |
[ ] |
How effective a material is as an insulator |
[ ] |
How effective a material is at conducting electricity |
[ ] |
How effective a material is as at absorbing carbon dioxide |
|
|
2.
|
If a material is a good insulator, what size U-Value will it have? |
|
[ ] |
Small |
[ ] |
Large |
[ ] |
Neither large nor small |
[ ] |
A negative value |
|
|
3.
|
A solar panel that contains water which is heated by radiation from the sun can be used for what purposes? |
|
[ ] |
Heat building |
[ ] |
Heat domestic water supply |
[ ] |
The heat cannot be transferred |
[ ] |
Heat both building and domestic water supply |
|
|
4.
|
What is specific heat capacity? |
|
[ ] |
The amount of energy required to change the temperature of 10 g of a substance by 1oC |
[ ] |
The amount of energy required to change the temperature of 1 g of a substance by 1oC |
[ ] |
The amount of energy required to change the temperature of 1 g of a substance by 1 K |
[ ] |
The amount of energy required to change the temperature of 1 kg of a substance by 1oC |
|
|
5.
|
Which of the following formulas is used to calculate specific heat capacity? |
|
[ ] |
E = m x c x Θ |
[ ] |
E = (m x c)⁄Θ |
[ ] |
E = m x Θ |
[ ] |
E = c x Θ |
|
|
6.
|
How much energy is required to heat a block of material of mass 4 kg by 10oC whose specific heat capacity is 800 J kg-1 oC-1? |
|
[ ] |
3,200 J |
[ ] |
32,000 J |
[ ] |
16,000 J |
[ ] |
1,600 J |
|
|
7.
|
Calculate the specific heat capacity of a material whose mass is 1 kg which required 300 J of energy in order to be heated from 1oC to 5oC. |
|
[ ] |
25 J kg-1 oC-1 |
[ ] |
50 J kg-1 oC-1 |
[ ] |
75 J kg-1 oC-1 |
[ ] |
100 J kg-1 oC-1 |
|
|
8.
|
What was the change in temperature of a material with a specific heat capacity of 1,000 J kg-1 oC-1, a mass of 2 kg which absorbed 500 joules of energy? |
|
[ ] |
0.25oC |
[ ] |
0.5oC |
[ ] |
1oC |
[ ] |
2.5oC |
|
|
9.
|
What are the units of specific heat capacity? |
|
[ ] |
J kg oC |
[ ] |
Kg⁄JoC |
[ ] |
J kgs⁄oC |
[ ] |
J kg-1 oC-1 |
|
|
10.
|
If a wall has a high U-value, will it allow more or less heat to flow through it than a wall with a low U-value? |
|
[ ] |
The same |
[ ] |
Less |
[ ] |
More |
[ ] |
Impossible to tell |
|
|
1.
|
What do U-Values measure? |
|
[ ] |
How effective a material is as a conductor of heat |
[x] |
How effective a material is as an insulator |
[ ] |
How effective a material is at conducting electricity |
[ ] |
How effective a material is as at absorbing carbon dioxide |
|
|
2.
|
If a material is a good insulator, what size U-Value will it have? |
|
[x] |
Small |
[ ] |
Large |
[ ] |
Neither large nor small |
[ ] |
A negative value |
|
|
3.
|
A solar panel that contains water which is heated by radiation from the sun can be used for what purposes? |
|
[ ] |
Heat building |
[ ] |
Heat domestic water supply |
[ ] |
The heat cannot be transferred |
[x] |
Heat both building and domestic water supply |
|
|
4.
|
What is specific heat capacity? |
|
[ ] |
The amount of energy required to change the temperature of 10 g of a substance by 1oC |
[ ] |
The amount of energy required to change the temperature of 1 g of a substance by 1oC |
[ ] |
The amount of energy required to change the temperature of 1 g of a substance by 1 K |
[x] |
The amount of energy required to change the temperature of 1 kg of a substance by 1oC |
|
|
5.
|
Which of the following formulas is used to calculate specific heat capacity? |
|
[x] |
E = m x c x Θ |
[ ] |
E = (m x c)⁄Θ |
[ ] |
E = m x Θ |
[ ] |
E = c x Θ |
|
|
6.
|
How much energy is required to heat a block of material of mass 4 kg by 10oC whose specific heat capacity is 800 J kg-1 oC-1? |
|
[ ] |
3,200 J |
[x] |
32,000 J |
[ ] |
16,000 J |
[ ] |
1,600 J |
|
|
7.
|
Calculate the specific heat capacity of a material whose mass is 1 kg which required 300 J of energy in order to be heated from 1oC to 5oC. |
|
[ ] |
25 J kg-1 oC-1 |
[ ] |
50 J kg-1 oC-1 |
[x] |
75 J kg-1 oC-1 |
[ ] |
100 J kg-1 oC-1 |
|
|
8.
|
What was the change in temperature of a material with a specific heat capacity of 1,000 J kg-1 oC-1, a mass of 2 kg which absorbed 500 joules of energy? |
|
[x] |
0.25oC |
[ ] |
0.5oC |
[ ] |
1oC |
[ ] |
2.5oC |
|
|
9.
|
What are the units of specific heat capacity? |
|
[ ] |
J kg oC |
[ ] |
Kg⁄JoC |
[ ] |
J kgs⁄oC |
[x] |
J kg-1 oC-1 |
|
|
10.
|
If a wall has a high U-value, will it allow more or less heat to flow through it than a wall with a low U-value? |
|
[ ] |
The same |
[ ] |
Less |
[x] |
More |
[ ] |
Impossible to tell |
|
|