Through the years, these dirigibles have not been used solely for sport. They've been known to transport airmail, contribute to weather research and have even been involved in military attacks. They can soar miles above the earth, giving passengers a bird's-eye view. Simple earth science principles make balloons really take off. Marquis explained the same principle of buoyancy that boosts a bubble to the water's surface is what lifts a hot air balloon.
Warm air rises.
It sinks, because the rock is more dense than water. Because cork is less dense than water. The same rule applies to a developing thunderstorm. This balloon hovers gracefully above a lake. As the sun heats the ground, a warm pocket of air forms.