Why is aluminum foil used to cook food

science / food (careful-which way is heat moving)

You can't wrap food going into an oven in material that might catch on fire, melt or build up pressure from steam and explode. Still, you want to retain the moisture in the food. What else would you suggest?

Sometimes I use it for easy clean-up. It's also helpful to cover food to keep it from browning too much on the top before it's thoroughly cooked.