This clip shows how a vacuum flask prevents heat loss. Detail of the design of the flask to prevent conduction, convection, radiation and evaporation is given. This includes the vacuum, silver-coloured inside and a lid.

First broadcast:
21 November 2008

This clip could be used to explain how a vacuum flask prevents heat loss. Following the clip, encourage pupils to undertake further research into preventing heat loss, in the classroom, home or in the design of a central heating system. Students could draw a diagram or build a model of to show how conduction, convection and radiation are prevented. They could experiment with different materials to gauge their insulating properties. The class could discuss their ideas in terms of efficiency and practicality. Would a design based on a vacuum flask be a good option for a domestic water tank?