Hot air balloons are based on a very basic scientific principle: warmer air rises in cooler air. Essentially, hot air is lighter than cool air, because it has less mass per unit of volume.
A cubic foot of air weighs roughly 28 grams (about an ounce). If you heat that air by 100 degrees F, it weighs about 7 grams less.
Therefore, each cubic foot of air contained in a hot air balloon can lift about 7 grams.
That's not much, and this is why hot air balloons are so huge -- to lift 1,000 pounds, you need about 65,000 cubic feet of hot air.
Hot Air Balloons are the oldest form of manned-air transport!
If you actually need to get somewhere, a hot air balloon is a fairly impractical vehicle.You can't really steer it, and it only travels as fast as the wind blows.
Again, hot air balloons are an ingenious application of basic scientific principles & many amazing things have come from that science.
Here is a video that helps explain how the first hot air balloon got off the ground....thanks to science.
Yes, hot air balloons are the way they are today because of the advancement in science. But looking at things in another perspective, hot air balloons have also helped science.
They have helped shape the way we use transportation, medical techniques, lighting up sporting events, fill companies use them for lighting and birds eye views for football games & scientists use them to gather vital info about the earth's atmosphere. So many magnificent things have come from the science used to lift a hot air balloon!