put hot air in it ;p hahhahahaHot air is lighter than the surrounding air as it is less dense (molecules move apart.) Therefore, it always wants to rise (as it does in your home, making higher floors...
make your own hot air balloon with a tissue paper. here's how---http://solospirit.wustl.edu/solospirit2/education/Ballooning/makeone.html hope that helped.. thanks..
A hot air balloon is powered by hot air, hot air is lighter (less dense) then the air outside of the balloon (More dense) Heat rises, so the heated air, pushes up into the balloon allowing the...