This practical is great at demonstrating heat loss from houses and also the effective properties of house insulation.
A small house needs to be made for each set, students may make houses from old paper boxes, sheets of this cardboard or other small boxes. They need to be around 30cm3 in size and need to represent a house so windows and doors will need to be cut out and a roof placed on top.
Insulating materials need to then be applied to the inside of the house. They will, in effect, be there to keep the heat inside the house that is created by as 12V lamp. Materials such as aluminium foil, bubblewrap, felt, cotton wool, corrugated cardboard, OHP sheets, etc can be used for the insulation.
Equipment required (per set):
The lamp must be a low voltage 12V type that will create heat but not too much. Mains lamps should never be used as they will get too hot. The lamp goes inside the 'house' and so the student must ensure that neither the house nor any insulating materials come into contact with the lamp as they may melt or burn. The lamp should only be turned on briefly.
- Materials to make 'house'
- Low voltage lamp in holder (12V 24W)
- Labpack and leads
- Insulation materials
- Glue, sticky tape, scissors etc
- Decorating materials (pens, pencils etc)
A datalogger with temperature sensor or an infra red (IR) thermometer may be used to measure how much heat escapes from the insulated house. IR thermometers work best as they can accurately measure the heat that radiates from the surfaces of the house which is a direct consequence of heat loss.
Students can experiment with different insulating materials and decide which are best for home insulation from the resultant heat loss figures they obtain.