Aluminium foil and cling film are often used to keep foods fresh and wrap up items placed in the fridge. When something is being kept out of the fridge for any time, such as when cleaning out the fridge, the consideration about keeping the item cool might arise. Aluminium foil is better to keep things cool because it reflects the light and does not absorb the heat as quickly.
Aluminium Foil Sides
There are two sides to aluminium foil, one shiny and one dull. When considering which side will retain the cool temperature longer, confusion might arise. There is no difference between the sides as far as keeping things cool is concerned. Ask a Scientist states that the difference relates only to manufacturing rather than the appearance.
Cling Film Advantage
While aluminium foil keeps things cooler and for longer, cling film is better at keeping food fresher, according to ISFAQ. This means that for food storage, cling film is the better choice while keeping things cool for the short term is ideal for the foil.
Students in science classes can turn the question into an experiment. Form the idea of which is better at holding cool temperatures and then form an experiment. For example, put the two materials in the freezer for one hour and then remove and allow them to sit for five minutes. Then check the temperature. Alternatively, wrap an item in both foil and wrap and put the item in the freezer. Remove after it freezes and watch how long it takes to melt.
Reasons for Holding Cold
Aluminium foil holds in cold for a few reasons. One reason is the reflective surface. Light bounces back from the foil, preventing it from warming. Aluminium is also thicker than cling film, requiring a longer period of time to warm up and thus keeping items cool longer. The metal material also contributes because the metal holds onto the cold.