Lift: Lighter Than Air Aircraft

Learn about the history and dynamics of hot-air balloons.

Transcript

Hi, my name is Dan, and I'm an Explainer at the National Air and Space Museum's "How Things Fly" gallery. Today we're gonna be looking at lighter-than-air aircraft. Behind me you'll see the Breitling Orbiter. It was the first balloon to travel around the world non-stop.

Let's look a little more into hot-air balloons. Right here we have a balloon. Now, when we fill it up with cold air and let it go, it's gonna fall right to the ground. So, let's try to fill it up with hot air and see what happens. As we fill it up with hot air, hot air is less dense than the air around it. What happens is the balloon is going to become buoyant, and is then gonna start to fly upwards.

If you guys ever get the chance to go up to Albuquerque, New Mexico, the first two weeks of October is the hot air balloon festival. There are hundreds of different shaped, sized, and colored hot-air balloons. The first hot-air balloon was invented by the Montgolfier brothers in 1783. The first hot-air balloons flew barnyard animals. After a safe landing humans soon took flight in hot-air balloons. Since then, hot-air ballooning has become a popular sport around the world. There are many different types of lighter-than-air aircraft. There are hot-air balloons, and there are blimps.

Oh, it looks like we're ready to go! You ready? Three, two, one, liftoff! Why did the hot-air balloon come back down to the ground? Well, let's look at that. As the bloom went up the hot air cooled down. As the air inside the balloon cooled down, it became more dense. The balloon then became heavier than the surrounding air around it and gravity pulled it right back down to the ground. That is how lighter than air aircraft work.