Final answer:
In common household aluminum foil, there is no designated non-stick side, and both sides can be used against food. However, for some specialty non-stick aluminum foils, the non-stick side is often the dull side.
Step-by-step explanation:
The question pertains to the properties of aluminum foil and the inquiry is related to which side of the aluminum foil is non-stick. In general, household aluminum foil does not have a designated "non-stick" side.
Both sides have very similar properties; the difference in appearance between the shiny and dull sides is due to the manufacturing process. In some specific brands, there may be a specially treated side that is labeled as non-stick. If that's the case, the non-stick side would typically be the duller side as it could have a thin silicone coating applied to it.
When using aluminum foil, if it's not specified as non-stick, either side can be placed against the food. During various experiments and investigations, such as determining the mass of the foil or testing it as a boat for cargo in water, the non-stick property is typically not a factor.