Hooked on Science: Hot air balloon

Materials

• 30-gallon clear trash bag
• 4-slice toaster
• Large tub

Instructions

• STEP 1: Place the toaster into the large tub. Plug the toaster into an electrical outlet.
• STEP 2: Turn the toaster settings to the highest and push down the levers until they lock.
• STEP 3: Place the open end of the 30-gallon trash bag over the tub. Hold the trash bag until it completely fills with hot air. Feel the sides of the trash bag. Are the sides hot or cold? Why? Let go of the trash bag. What happens? Why?

Explanation

The flow of rising hot air from the toaster creates a convection current inside the trash bag. As a result, the air is heated, and the trash bag expands, becomes less dense and eventually lifts into the air.