This instructable will show you how to make a hot air balloon. This balloon will not use any sort of flame to make this, though. Instead, it uses the sun to heat the balloon. I saw this at American Science & Surplus, but it was $17.50 USD, so I wanted something cheaper; I went out and made my own!
The black color of the trash bags makes the air inside heat up. Everyone knows that hot air rises, thus making the balloon rise.
These are the things you need:
30-Gallon Black Trash Bags
A large roll of duct tape (preferably black color), or a large roll of clear packaging tape
A LARGE, dirt free environment without wind
Something to pump air with adequate volume (like the exhaust port of a shop vac)
Two or more hands