P2 - Energy Transfer By Heating

Question 1

How do houses lose heat?

Answer 1

Doors - Conduction
Windows - Conduction
Roof - Radiation
Walls - Conduction & Radiation

Question 2

Thermal Conductivity

Answer 2

To reduce the energy transfer as much as possible​,
The thermal conductivity should be as low as possible​,
The thickness of the insulating layer should be as thick as is practically possible​

Question 3

Describe loft insulation and what happens.

Answer 3

Made of fibreglass​
Air is trapped between the fibres​
More layers = greater insulation​
Reduces energy transfer by conduction​

Question 4

What is a thermal conductor?

Answer 4

A material that easily allows thermal energy through

Question 5

Which is the best insulator?

Answer 5

Wood

Question 6

Why is loft insulation so effective?

Answer 6

It traps air which helps to reduce heat lost from the home

Question 7

What would make the best material for wrapping around a mug to keep a hot drink warm for as long as possible?

Answer 7

Bubble wrap would be the best material for wrapping around a mug. It has trapped air which is a good insulator.

Question 8

What happens to the molecules in a liquid as it gets hotter?

Answer 8

Molecules will speed up as a liquid gets hotter.

Question 9

What happens to the molecules in a solid as it gets hotter?

Answer 9

The molecules vibrate faster. The molecules in a solid are already vibrating.

Question 10

When doing an experiment to find the specific heat capacity, which of these items of equipment is not needed?

Answer 10

A force meter isn’t needed. To find the specific heat capacity a heater is needed to provide energy and increase the temperature of the material.

Question 11

If the same amount of heat energy were to be provided to a block of twice the mass of the same material, what would happen to the temperature rise?

Answer 11

The temperature rise would be half as much.

Question 12

What is the specific heat capacity formula?

Answer 12

Change in thermal energy = mass × specific heat capacity × temperature change
Specific Heat Capacity = Energy / mass x temperature change

Question 13

What is the definition of specific heat capacity?

Answer 13

energy needed to raise the temperature of 1kg of a substance by 1°C

Question 14

What is the definition of thermal conductivity?

Answer 14

property of a material that determines the energy transfer through it by conduction

Question 15

Why is fleece lining in a fleece jumper effective?

Answer 15

Fleece lining is effective as it traps body heat and sustains the warmth. It creates a comfortable layer of insulation

Question 16

How can you reduce heat loss in a house?

Answer 16

1. fitting carpets, curtains
2. Heat loss through windows can be reduced through double glazing.
3. Heat loss through walls can be reduced using cavity wall insulation.
4. Heat loss through the roof can be reduced by laying loft insulation.

Question 17

Plan an experiment to test which insulator was the best.

Answer 17

1. Cover your beaker with the insulator.
2. Fill it with hot water.
3. Put the thermometer in the beaker.
4. Set a timer for 10 minutes and see which insulator has the highest temperature.
5. Repeat with each insulator