Insulation

Question 1

Double glazing

Answer 1

Double glazing adds an extra pane of glass to each window. This means that there in a layer of air or vacuum between the two panes.
This helps to prevent heat loss by conduction.

Question 2

Loft insulation

Answer 2

Loft insulation is plastic foam containing trapped air, which acts as an insulator.
Acts as an insulator to stop conduction of heat through the food tiles.

Question 3

Draft excluders

Answer 3

Fraught excluders are hairy or spongy strips that are placed under doors.
Used to prevent the movement of convection currents.

Question 4

Curtains

Answer 4

Curtains reduce heat loss by covering up gaps around windows through which convection currents pass. Curtains reduce heat loss by convection currents.

Question 5

Cavity wall insulation

Answer 5

Cavity wall insulation involves placing a layer of plastic foam insulation in between two layers of outside walls. This prevents heat loss by both conduction and convection currents (convection currents in the cavity).

Question 6

Foil behind radiators

Answer 6

Placing a sheet of shiny foil between radiators. This prevents heat radiation reaching the wall and conducting outside. Instead, it is reflected back into the room (foam insulation prevents convection currents).

Question 7

Thermograms

Answer 7

Thermograms are useful for examining heat lost from a house, as they show the temperature distribution over its surface. The yellow and orange roof and windows are the warmest - these are the most poorly insulated areas of the house. The dark walls are the coolest - these are the best insulated areas. A poorly insulated house loses more energy and so costs more to heat. Using more energy to heat the house also creates more pollution, particularly carbon dioxide.

Question 8

Birds feathers

Answer 8

Birds’ feather are good insulators of heat. The feathers trap air, which decreases the bird’s heat loss.

Question 9

Where is heat lost through a poorly insulated house?

Answer 9

Heat is lost from a house through the walls, floors and windows. For example, heat rises when air particles move upwards by convection and is lost through the roof by conduction and radiation.

Question 10

Air and plastic

Answer 10

Air and plastic are good insulators, and they reduce heat loss by conduction. The plastic foam prevents the movement of air in the cavity, which reduces heat loss by convection.

Question 11

Thermos container

Answer 11

A thermos container has two walls separated by a vacuum. The inside of the thermos also has a silver coating. The vacuum stops thermal energy moving between the walls by conduction or convection. The silver reflects thermal radiation. This allows the drinks in the thermos to be kept hot or cold.