A food delivery courier operating in a cold city uses a specialized insulated backpack to keep hot meals warm during transport. The walls of the backpack are lined with a thick layer of expanded polystyrene (EPS) foam.
Explain how the thick EPS foam lining helps to keep the food warm.
A colleague suggests: "We can replace the bulky foam backpack with a thin backpack that has only a shiny, silver-coloured foil inner lining to keep the food just as warm."
Discuss whether you agree with this colleague's suggestion.