Helium and hydrogen - Small atoms with large forces - When I tried to send my little sister in the air
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Written in 9th grade, part of Science Fair
A short movie about the project, see above or click here
Every year at the local market, one can see balloon vendors that have their helium balloons tied in a cement lump. I have always wondered if my little sister Sara would fly away if she holds in all balloons.
There was a man in the 80s, Larry Walters, who flew with helium balloons. His plan was to float around, in his chair, at 10 m (30 ft) height. But he made some miscalculations. Quickly he rose to 4600 m (15000 ft) height.
At the beginning of the 20th century, airship called Zeppelins were used as a means of transportation. There were regular routes between Europe and both North and South America. The advantage of the Zeppelins was that they could fly long distances and they could transport relatively heavy loads and compared to ship they were faster.
The time between the wars, Germany stood for these routes and they used hydrogen in their Zeppelins. They used hydrogen, because the biggest supply of helium was in the U.S and Germany was not allowed to take part of it. The downside with hydrogen is that it is very explosive. When it comes in contact with a combination of fire and oxygen, eg a spark, it can explode. The reaction becomes 2H2 (g) + O2 (g) + spark -> 2H2O (g) + 576 kJ, it is water and a large amount of energy. (In comparison, 1g carbohydrate gives 17 kJ, and here only 4 hydrogen atoms give 576 kJ). What an enormous amount of energy these small atoms have!
Explosion is exactly what happened 1937 outside New York. It was the German airship Hindenburg that exploded. After this well-known disaster, the usage of hydrogen balloons was cut down and the demand of zeppelins decreased.
Now the time is changing. The company Aero Corporation in California plans to, before 2016, build 24 helium filled Zeppelins. Their Zeppelins called Aerocraft Cargo, will be used for transportation of goods. The advantage is that they are environmentally friendly, the pollution is much less than ordinary aircrafts for transportations, and they can also lift very much. Aeros Corporation use Zeppelins that can transport up to 200 tones, like for example wind turbines. Another big advantage is that the airship lands vertically, so no big runways are needed. The advantage compared to trains and trucks is that they are not dependent on roads and railways and not dependent on water and can therefore carry goods such as wind turbines to otherwise inaccessible places.
In this project I will investigate if it is possible to lift my sister Sara with balloons. I will make a practical experiment, where I try to lift Sara with hydrogen gas and/or with helium balloons. I will also learn more about how small atoms can have large forces to lift.
The chemistry behind hydrogen and helium
Hydrogen is the most common element in universe, 90% of all elements are hydrogen. Helium is the second common element. Both elements exist in huge amounts.
Helium can be produced from natural gas by fractional distillation. Fractional distillation means that a variety of gases are cooled to a liquid. Different substances have different boiling points. When raising the temperature, the elements vaporate one after one according to their boiling point, for example helium has its boiling point at -236 °C (-441 °F). At this temperature one gets pure helium.
Hydrogen can be produced by electrolysis or chemically.
Hydrogen and helium look very similar. Hydrogen (H) has number 1 in the periodic table and helium (He) has number 2. Hydrogen has only one electron in its shell and is therefore reactive. Helium has full scale and is therefore called a noble gas, and is not as reactive.
Why does a balloon filled with helium or hydrogen lift?
Around us there is air. Hydrogen gas and helium has a lower density than air, it means that they weigh less than air. Therefore helium and hydrogen rise, and have lift force in air. Helium has a slightly lower lift force than hydrogen.
Pure hydrogen has a lift force, that can lift 1,2 kg / m³.
Pure helium has a lift force of 1.1 kg / m³.
To calculate the density (p), one uses the formula p = m/V, the mass (m) is measured in kg and the volume (V) in m³.
Hydrogen gas has a density of 0.089 kg / m3, air 1.204 kg / m3 and helium 0.18 kg / m3.
Questions to solve:
1. Will my little sister Sara with equipage fly away if she gets all the balloons (30 balloons) of a balloon vendor ? (Experiment 1)
2. If it is not possible to lift Sara with equipage, how many balloons are needed to lift her? (Mathematical calculation)
3. How much can 30 balloons lift? (Mathematical calculation)
4. Can Sara's doll, the doll's dog and a GoPro camera be lifted by 30 balloons? (Experiment 2)
5. How many balloons are needed to lift the doll, the doll’s dog and a GoPro camera? (Mathematical calculation)
Plan A with homemade hydrogen gas:
For the experiment in which I tried to lift my sister with hydrogen balloons, I used: 30 latex balloons (á 3.0 g and volume 12 liter), little sister Sara with clothing (28.0 kg), camping chair in kids size (1.1 kg), grandmother's dog Tezzi (5.4 kg), umbrella (0.50 kg), doll with plastic dog (31g), airgun, GoPro camera (155g), string 10 m, gift string 40m, fishing rod with a long line - 200 m, and home made hydrogen gas.
For hydrogen production I used: Sodium hydroxide (NaOH), crushed aluminium (Al), water and homemade "hydrogen producer."
To make the "hydrogen producer" I used: 2 large empty protein containers with lids, top of plastic bottle with lid, plastic bottle with large opening, about 2.5 meter plastic hose - about 3 cm in diameter, two-component adhesive, silicone, plastic foil and duct tape. See picture beside.
Plan B with purchased helium:
For the experiment in which I tried to lift my sister with helium balloons, I used the same materials as in Plan A. But instead of hydrogen gas, I had helium in cylinders, purchased at “Teknikmagasinet”.
To find facts and mathematical formulas I googled and read in scientific journals. I calculated the volume of a balloon using the formula for the volume of an ellipsoid (see mathematical calculations I).
I counted how much lift force both hydrogen balloons and helium balloons have (see mathematical calculations II).
Experiment 1, to lift Sara:
I filled 25 balloons with helium (after that the gas ran out) made knot and tied them together with gift string.
I tied the camping chair in the anchorage.
I tied the string with the balloons in the camping chair.
Sara sat in the chair armed with umbrella with nail on top and held tight to the chair.
The dog sat down in Sara's lap.
I cut the string between the seat and the anchorage and observed what happened.
Experiment 2, with the doll:
I tied the strings of the balloons to the doll and the dog.
I tied the GoPro camera to the balloons.
I tied the beginning of the fishing line, from the fishing rod, to the doll. It is in case the camera and the doll flew away.
We dropped the anchor rope to the balloons, and observed what happened.
I tried, according to plan A, to produce hydrogen gas by myself. After I made hydrogen gas and filled two balloons (for the formula for manufacturing, see mathematical calculations and formulas VI), I cancelled plan A, because the pressure in the reactor vessel was too high. I turned then to plan B, and filled the balloons with helium from the tube instead. There was not enough helium for 30 balloons, only for 25 balloons.
Results of my questions:
1. My little sister Sara did not fly away with the balloons. (Experiment 1 and Plan B)
2. To lift Sara, grandmas dog, umbrella and chair, we would need more than 3400 helium balloons or almost 3100 hydrogen gas balloons. This means that we would need more than 100 times more balloons than planned. For calculations, see mathematical calculations III.
3. The 30 helium balloons, the balloon seller holds, can lift about 306 g, and if it were 30 hydrogen balloons they would be able to lift 342 g. For calculations, see mathematical calculations IV.
4. The doll, the doll's dog and GoPro camera quickly flew away when we dropped the anchor rope. This despite that we only had 25 balloons. This is because 25 helium balloons have a lifting capacity of 255 g and the equipage only weighed 186 g.
5. Only 19 helium balloons would be needed to lift the doll, the doll's dog and GoPro camera with a total weight of 186 g. For calculations, see mathematical calculations V.
In the production of hydrogen: When sodium hydroxide is mixed with water, dangerous gases and corrosive liquid as lye are produced. The gases are dangerous to inhale and the liquid is corrosive if you get it on your skin, eyes or clothing.
Hydrogen gas is explosive, it may explode if it comes in contact with oxygen and fire. Therefore, I had glasses, gloves, earmuffs and thick protective clothing. I was outdoors, partly to not inhale dangerous gases, but also not to cause damage to the house.
During refilling with helium my only estimated risk was that the balloons could explode and I would get an earache. I therefore used earmuffs. When handling gas in the pressure vessel, there is a risk of explosion at high temperatures, but that risk did not exist here.
To prevent that Sara would fly away uncontrollably, she had an umbrella with a nail on the top, to peck hole in the balloons with if she wanted to get down. If she could not peck holes in the balloons, because her arms were too short, she could use the umbrella as a parachute. If she would lose the umbrella or not dared to jump, I was prepared to shoot down the balloons one by one with the airgun.
Before I started the project, I did not know if it would be possible to lift Sara. But quickly after mathematical calculations, I realized that it would not go. I conducted the experiment anyway, to complete the project.
The idea was to fill 30 balloons with my homemade hydrogen gas. The pressure in the reaction vessel was too high and the gas leak became too large. After two filled balloons, I gave up the hydrogen production. Then I went over to plan B, to fill the balloons with helium from tubes instead.
If I would make this experiment again, I would not produce my own hydrogen, partly because there are risks involved, and partly because it was complicated and I spend too much time on this. I would use helium from the beginning. I would not have a dog in the experiment because it is difficult to make dogs do what you want. The dog did not seem to have so much interest for any balloon trip.
According to the calculations there should be enough helium for 30 balloons. By accident I dropped some balloons so they flew away and some broke. If I would redo the experiment, I would have made sure that the helium tubes would have helium gas for more than 30 balloons.
Before the experiment, I did not check the purity of the helium. I assumed that it was 100% helium. But now afterwards I understand that the helium was sold as balloon gas which is not 100% helium. So many calculations are not accurate because I assumed it was pure helium.
Before the experiment I did not think about that balloon trips are dependent on weather conditions. It would be the best if there was no wind and it was clear weather. Even though it was overcast and a bit windy, I had to carry out the experiment, because of time constraint.
Usually one uses a formal language in lab reports and scientific papers. But I have chosen to write in everyday language, For example use "little sister Sara" instead of "Test person 1" and "grandmother's dog" instead of "test dog 1".
The aim of this project was to investigate if I could send away my sister with 30 balloons. If that would not work, I would figure out how many balloons were needed for that. I also wanted to investigate whether one can lift a doll, the doll's dog and a GoPro camera (doll's equipage) with 30 balloons. I wanted also to understand more theory behind balloon flights.
I came to the conclusion that it is not possible to send away my sister with 30 balloons, but it is possible to send up the doll with its equipage. 3500 helium balloons are needed to lift my sister and only 19 balloons are needed for the doll.
One does not need to be afraid that kids or dogs would fly away with all the balloons from balloon vendors at the markets.
Small atoms like hydrogen and helium have huge amount of energy through their lift capability in the form of potential energy. It is because of the difference in density compared to the surrounding air. Therefore, one can say that small atoms have large forces. In addition, hydrogen has large chemical energy, even so much energy that spaceship are driven by it.
Mathematical calculations and formulas:
I. I assume that a balloon has a shape of an ellipsoid. The formula for volume is V= 4/3 pi x abc.
a1,5dmb =c 1,4dm So volume 12dm3.
II. To calculate the lift force of a hydrogen balloon, I first found that 1 m3 of hydrogen gas has a lift force of 1.2 kg, so 1 liter has a lift force of 1.2 g. My balloon has a volume of 12 liter, so I multiply 1.2 g with 12 liter and the product is 14.4 g. The balloon has a mass of 3 g, so I subtract 3 g from 14.4 g and the difference is 11.4 g, which is the lift force of a hydrogen balloon at 12 liters.
I found that the formula for how much hydrogen balloons can lift is 11.4 g x n, where n = number of balloons.
To calculate the lift force of a helium balloon, I first found that 1 m3 of helium has a lift force of 1.1 kg, so 1 liter has a lift force of 1.1 g. My balloon has a volume 12 liter, so I multiply 1.1 g with 12 liter and the product is 13.2 g. The balloon has a mass of 3 g, so I subtract 3 g from 13.2 g and the difference is 10.2 g, which is the lift force of a helium balloon at 12 liters.
I found that the formula for how much helium balloons can lift is 11.4 g x n.
III. Number of balloons to lift Sara and equipage. The total weight is 35 kg or 35 000 g. The lift force of a helium balloon is 10.2 g. This gives 35 000g / 10.2 g = 3431 ie more than 3400 helium balloons of this size. The lift force for a balloon of hydrogen is 11.4 g. This gives 35 000 g / 11.4 g = 3070, ie nearly 3100 hydrogen balloons.
IV. To figure out how much 30 hydrogen balloons can lift, I use the formula 11.4 g x n. 11.4 x 30 = 342 g ie, 30 hydrogen balloons can lift about 340 g.
To figure out how much 30 helium balloons can lift, I use the formula 10.2 g x n. 10.2 x 30 = 306 g ie, 30 helium balloons can lift more than 300 g.
V. Calculation of how many helium balloons that would be neded to lift the doll with equipage, total weight 186g: 186g / 10.2 grams = about 19 helium balloons.
VI. The chemical formula when I produced hydrogen gas is
6H2O + 2Al + 2NaOH -> 3H2 + 2NaAl(OH)4.
Thanks to ..
I want to thank my family and my cousin Daniel who helped me with the experiment. I also want to thank my sponsor, “Hörntanden”, who has sponsored the project with materials and equipment.
# ballongfärd balloon flight adam kutti science 123 örebro