According to this article, it’s difficult to tell the two apart, especially since tin foil isn’t widely used anymore. Their appearance is so similar that most people would have to physically use both to compare. However, tin foil is generally “less sturdy and stiffer compared to aluminum and can also leave a bitter taste in the food.”
Real tin foil is currently used more for things like electrical capacitors than food prep or storage. Tin foil is rarely found in a grocery store. Instead, aluminum is the material of choice to cover your food. In fact, the foil roll in your kitchen drawer is made up of approximately 99% aluminum alloy.