Yes, aluminium foil does reflect heat. It is known for its ability to reflect thermal radiation, which is one of the reasons it is commonly used in cooking and food storage.
When heat comes into contact with objects, it can transfer through conduction (direct contact), convection (movement of fluids), and radiation (emission of energy in the form of waves). Aluminium foil primarily excels at reflecting radiant heat.
The shiny surface of aluminium foil reflects about 80-90% of the radiant heat that hits it. This makes it an excellent barrier against heat, which is why many people use it when storing food or cooking. For example, when lined with aluminium foil, a baking pan can help to evenly distribute heat, or wrapping food in foil can keep it warm by reflecting heat back towards the food.
In summary, aluminium foil is effective at reflecting heat due to its reflective properties, making it a useful tool in various cooking and insulation scenarios.