Imagine you're at a hot air balloon event. The balloonists are
busy preparing for flight. They spread out the enormous
balloons on the grass and check all the lines. The talk is all
about today's temperature, wind speed, and direction. Some of
the balloonists have turned on their gas burners and point
them into the open end of the balloon. You tilt your head back
to watch them lift off the ground and fill the sky with a
rainbow of colors.
They're floating away. Floating away? But how? Did you ever
wonder why hot air balloons float?
You may already have some ideas. Think about them and then
choose one of the options below that seems closest to why you
think balloons float.