Death of the Balloon Woman

Sophie Blanchard floated through the French Revolution, Napoleon and eventually fell to earth in her flaming balloon.

Hot air, a temperature greater than its surroundings is less dense than its surroundings. This means that heavier gas flows into the volume it occupies pushing the air upwards. The interplay of gravity and density are the magic ingredients of what we term convection. Now if the material involved contains energy, then the motion of material means the motion of energy. Heating things up in a gravitation field does lead to convection, but a lighter gas at the bottom of a column also experiences this effect.

If you were to split diatomic oxygen (16 +16 = 32 u - unified atomic mass) into atomic oxygen (16 u) this lighter gas would rise, not because it is hotter but in the system having something more massive lower in a gravitation field at the expense of something less massive is a lower energy state. Here the term field describes where gravity is and not the action of gravity. The field refers to a volume I am thinking off and at every location in that volume the force of gravity act.

Now splitting oxygen molecules into atoms can be done, but very quickly the oxygen sticks back together or sticks to something else meaning splitting does not last that long.
But it is possible to deactivate the two binding sites of oxygen with light weight plugs and this will float. The plugs have to be lighter than oxygen, because that would mean the total weight would be heavier than two oxygen. We can plug it with hydrogen, then it will float. This will float, convect, up, high up into the air until ... it becomes.... clouds. Clouds are up there due to convection, and due to gravity. The cloud goes up, the balloon goes up because the air that it is heavier than is falling down. Clouds float because of gravity.

Before returning to France and the first balloon flights let's go to the international space station (ISS). Here a cup of tea is a real drama. On earth the flame heats the bottom of the water, and thank you very much that little bit of water, is a little bit hot, and politely makes way for denser cold water, which is a little bit colder. This polite interchange enables the orderly distribution of heat through out all the pan of water being heated. Now chew on this, water does not rise because it is hot, it rises because it is less dense. Now the opposite could happen if we could some how make something more dense when it heated up. Then if we applied the heat at the top it would sink to the bottom. Will scientist ever do this? Well, if we look to the ice sheets in Greenland (a Danish territory in the Atlantic Ocean, thinking of Independence with the aid of Chinese money) we see ponds of water melting under the sun. The ice is white, due to the many little fractures inside scattering the light (you know that your ice cubes in your drink is transparent) . Light hits the cracks and gets scattered back into space, or into the explorers eyes causing snow blindness. Not so for liquid water, there are no cracks and most of the light energy is absorbed. The water heats up and falls off the ice down crevices. Worst of all when it finds its way to the base of the ice-sheet, the ice-sheet floats and rolls into the sea.

Back in the space station, lighting a match is a problem as convection the normally draws fresh oxygen into the radical molecule zone (flame) isn't at work. Now it is not that there is no gravity, it is nearly the same as it is on earth - sitting at about 90 %. If there is gravity things accelerate (that's Einstein's insight) and in the space station things are accelerating, falling and thankfully not hitting the ground. To quote Douglas Adam, it is being thrown at the ground and missing. So everything is busy falling, and there is not much difference between any two objects.

Lets get back to the pan. The water would stick inside due to surface tension. Then the point near the heat source would heat, and heat, no convection mixing, heat and eventually boil into gas firing the pan of water into the space station, frying the electronics possibly setting of a chain of spectacular explosion. Well perhaps not the last part, I was just letting my imagination run to produce content for my typing practice.

Does understanding convection matter? People in the doesn't matter camp tend to have the knack of caring the day and taking over. They are cool. In convection terms they should sink to the bottom of the argument. But on a serious note understanding is just not their thing, it just gets in the way.

To get some perspective on this it is insightful to find out just what people were thinking as they used the paper from their paper factory to set the first balloon aloft in Paris. As you know Aristotle is a great guy. You find this out by writing this a hundred times. Others who are way more switched on than you can work it out by about 70 times. So what Aristotle said was that smoke is from fire, and fire one of the four elements (Aristotle had 5 elements)... fire that is in heaven (up). So all think kind of know where they should go, fire up, earth down, and water actually moves until it finds it way to the sea. As an side as the sea never fills up that means there is one big sink hole some where. But what you need to make a balloon rise is smoke lots of uppy up type smoke. I think if you were in Paris back in the day and you tried to spread any of the high fluting book learning you would get a cobble stone to the back of the head. Then you clothes stripped and thrown in the smokey fire. There would be the odd momentary reflection, "Did you hear anything Francios?". "Non, non I did not, Jean-Paule-Baptiste-Saint Etteine-Le Carre, Vola the balloon it has now enough of le smoke, it is how you say totally awesomely going up."

Next probleme women going up in balloons. We have tried the duck and the sheep, but listen to the Podcast about the police injunction to stop a female in a balloon. For this we don't have to consult Aristotle. The short argument is rather obvious: women die at altitude.

I think you really have to get into the fame of thinking at the time. Balloons make the event authentic. It is kind of like the cake at a wedding, or in Australia sausages at a barbeque. You can tell a serious dictator by the quality of his balloon. So you can imagine Napoleon being none too impressed when his ballooner totally lost control and got blown to Rome, and then laughed at. He was gone and enter the balloon woman who is going to die later on in the Podcast.

I think it is fitting to finish up with Napoleon's coronation (You can call me Emperor now)
Balloon. Set aloft from Notre Dame cathedral with 3000 lights in the shape of a crown. Unmanned, but French history at its best. A little bit of research, and it was this balloon that was blown to Rome some 46 hours later.


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