Insulation  To understand how insulation works

Double Glazing  Which of the statements about the double glazing are true?  Our windows will keep heat in the home  Heat energy easily escapes from the window  Radiation can pass through the gap  Conduction can take place through the gap  Convection can take place through the gap  Conduction cannot take place through the gap  Convection cannot take place through the gap  Heat energy can reflect back into the house

Double Glazing  The true statements about the double glazing were: -  Radiation can pass through the gap  Conduction cannot take place through the gap  Convection cannot take place through the gap  Heat energy can reflect back into the house  Being semi-reflective light can enter, but some heat energy is retained in the home, being reflected back in

Radiation  Your task is to design an experiment which can keep 200ml of boiling water as hot as possible for as long as possible  Teams will be out when their water drops by 10ºC  The team which has their water above 90ºC for the longest will be the winner…

Radiation Experiment  This experiment consists of the following rules: -  You may only use 4 of the following items: glass beaker; tin beaker; plastic beaker; bubble wrap; foil; cotton wool; black paper; white paper; wool; and cardboard  You may only use 1 piece of each of the above  You must use 200ml of boiled water  The winner is the team whose flask takes the longest to drop 10ºC  Draw and label your design – make sure you label the 4 pieces of equipment you have chosen and why

Results  Can you explain your findings: -  Which set-up resulted in the temperature staying high for the longest?  What has the colour got to do with the temperature transfer?  What did the cotton wool / bubble wrap do etc…  All objects continually emit / absorb thermal radiation  A hot object emits more heat radiation than it absorbs (cooling down)  A cold object emits less heat radiation that it absorbs (warming up)

Heat Transfer  Something which slows down the rate of heat transfer is called an insulator  If you can reduce the amount of conduction, convection and radiation then the amount of heat transfer will be reduced, keeping the water’s high temperature for longer  The plastic beaker works as an insulator, not allowing convection to take place between the liquid and the solid plastic beaker  The tin foil is poor at emitting infra-red radiation, so not much energy is transferred through the foil (it reflects back)  The bubble wrap is good insulator as the bubbles of air reduce the amount of conduction which can take place  The cotton wool is also a good insulator, reducing the amount of conduction which can take place (lots of air spaces)

Cooling  Look at the following experiment – write a conclusion for the results with as much scientific knowledge as possible… Time (mins) Temperature (°C) ABCD

Conclusions  Tube A – uncovered tube loses heat quickest – heat is radiated from the tube more readily  Tube B – aluminum foil results in less heat loss – some heat is reflected back into the tube  Tube C – fibre glass wool retains most heat – glass fibre seems to be a better insulator  Tube D – covered with glass fibre wool + aluminum foil on the outside is the best arrangement for insulation, combining the properties of both