Take an empty can. It needs to still have its ring. Fill the can about 1/3 full with water. Pull the ring up so that it is vertical. Put a glass rod or similar through the ring and suspend the can through the ring of a ring stand. Be careful so that the rod does not slip off. Use tongs or forceps to hold a small piece of potato chip. Light the chip with a match and hold it under the can. The water heats up. Use this equation to find the amount of energy stored in the chip (or pretzel, peanut, whatever).
Heat gained or lost = (specific heat of substance) x (mass of substance in grams) x (temperature difference)