Balloons float because they are filled with helium! Balloons can be filled with different types of gas. ... Other gasses are very light and will float away from the surface. One of these gasses is called helium.

What can you put in a balloon to make it float?

Because Helium gas is lighter than air, but it is not the only gas we can fill the balloon, we may use hydrogen gas as well. The density of hydrogen gas is 1/2th of the mass of helium gas so we can consider it to make a floating balloon. Air can also be used to fill the balloon.

Do balloons filled with air float?

A hot-air balloon floats in the atmosphere, whereas a typical balloon filled with air will not float. When air is heated, it expands and becomes lighter than the cooler air it displaces. Hot-air balloons will rise rapidly in cooler air.