Men have dreamt of flying since ancient times. Just think of the myth of Icarus in Greek mythology… and surely also many more ancient populations throughout history have also had this dream.
It is however thanks to a Greek scientist, Archimedes of Syracuse (287-212 b.C.), who by formulating his famous principle revolutionized the world of navigation and flight, if today we can fly by an air balloon.
His principle states that: “Any object which is wholly or partially immersed in a fluid is buoyed up (=galleggia) by a force equal to the weight of fluid displaced“. Applied to gases, this means that any object can float in the air if its density is lower .
Therefore according to Archimedes’s principle, balloons, inflated with hot air, can fly.
The Chinese already used small air-balloons made of paper for military communications in 3rd century a.C.
But we have to wait until 1783, in Paris, to see the first “hot air balloons” as we know them: the Montgolfier brothers invented them and succeeded in flying them with someone on board. Modern hot-air-balloons are not very different from those invented by the Montgolfier brothers. Of course today, materials and techniques have improved.
A hot-air-balloon is composed of:
– a big balloon made of nylon ( a fireproof material);
– a basket for “passengers”, tied to the balloon;
– a burner full of propane gas.
As you can see in the picture, when the air contained in the balloon is warmed up, the balloon starts to move up in the air. Think that a hot-air-balloon can reach 20.000 metres of height!! More than an airplane!
Hot-air-balloons can’t be “driven” but can only go up and down by reducing the temperature of internal air. The wind will determine their direction.
I’ve never flown on a hot air balloon, but I think it would be an incredible and really spectacular adventure, don’t you think so?. 🙂