Why do hot air balloons fly? How to make a balloon.
Quite often you can hear the opinion that gas is a dangerous substance. Is not true statement. Why does it “happen” so often?
The fact is that the word "gas", like many other words in the Russian language, has several meanings (definitions). In its “main” meaning, gas is a state of matter (any substance can be solid, liquid and gaseous). And in one of the additional meanings, the concept of gas means household flammable gas used in the burners of gas stoves (usually methane).
What gas is used to inflate balloons? If the ball “flies”, then you can be sure that it is not inflated with the same gas that is supplied to gas stoves. Only a very light gas, which is much lighter than air, can support the ball in the air. Propane and butane are heavier than air, and the ball would lie on the floor. Methane is a little lighter than air, but still its lifting force would not be enough to lift an “ordinary” small balloon into the sky: only a huge balloon filled with methane could rise above the ground - and then extremely “sluggishly”: it would have a very low lift.
What kind of gas can easily lift any or any gas into the air? There are only two such gases: hydrogen and helium. Both of these gases are elementary substances and are listed in D.I. Mendeleev’s periodic table as numbers 1 and 2. In terms of their prevalence in the Universe, it is similar: hydrogen takes first place, and helium takes second place. In terms of “lightness”, these gases also occupy first and second places (hydrogen is the lightest, and helium is only slightly heavier) and are far superior to all other gases. In terms of the size of atoms, they are also leaders, although here it’s a little vice versa: helium has the smallest atom, and hydrogen takes second place.
But this seems to be the end of the similarities between these gases. Hydrogen is a very active element, extremely flammable and explosive: even more dangerous than household propane. And helium is a completely inert gas that does not react with any known substance, therefore it cannot burn or sustain combustion, and also cannot cause poisoning. According to Russian and European standards, as well as in accordance with the rules fire safety for pumping balloons Only helium or ordinary air is used. ()
Is it safe to inhale helium from a balloon? It is quite safe, if, of course, we are talking about helium itself, and not bacteria or other side factors that may be present. Helium, in a chemical sense, is even more “neutral” than nitrogen, of which it mostly consists earth's atmosphere. Helium is used as a component of the breathing mixture by scuba divers when working at great depths, since it practically does not dissolve in human blood.
An oval on a stick is the first association children have with the theme of balloons. You probably already noticed that the first drawing is a drawing of a hot air balloon, the first finished picture on the mosaic is a hot air balloon. After all, children simply adore them, and drawing one is not difficult. Do you know why all little children love balloons so much? It would seem, what's wrong with that? Nothing special at all, just an ordinary round rubber ball, which, as soon as you touch it, immediately bursts! So let's think about this topic together.
How did it all start?
Let's remember how Winnie the Pooh tried to get to the hive on balloon, and Piglet wanted to give it to Eeyore for his birthday. Remember how Dunno and his friends flew on a huge balloon, and a huge bunch of balloons was able to lift an entire house into the sky in the cartoon “Up”? Why do you think a good half of children's fairy tales and cartoons cannot do without such an insignificant and inconspicuous detail as balloons? And all because this simple toy contains all the power of childhood, with its ability to enjoy little things, be surprised by new things, fantasize and dream. Their ability to stay under the ceiling for a long time, and just imagine, not fall! And, of course, because they are colorful, different shapes and create a festive atmosphere in any situation.
What does it look like now?
Balloons are faithful assistants to clowns, wizards and, most importantly, parents who are trying to entertain children. Pop as many balloons as possible, find clues or souvenirs inside them, collect a certain number of identical balloons, build a pyramid of balloons - you can come up with a huge number of such competitions! And it is these games that perform not only an entertaining, but also a developmental function. You can decorate a balloon, glue legs and antennae to it, and off you go ladybug or some other bug. But most importantly, the balloon will be a wonderful gift for a child's birthday. After all, from balls you can create incredible and even gigantic structures in the form of cakes and pastries, motorcycles and cars, flowers and animals, houses and castles, in general, everything you can wish for and imagine. Children never get tired of such a gift; they are ready to watch and play with it as long as it is nearby. To give your child a bright, magical and unusual holiday that will be remembered for a lifetime, you don’t have to be a wizard. It is enough to show a little imagination, and let your baby keep in his heart the feeling of joy, happiness and magic that will be given to him!
And finally...
You can’t bring back childhood, it’s here, it’s now. Give joy and celebration to your children exactly when they need it. Children grow very quickly, interests change, views change. Be on the same page with your child and everything will definitely work out for you. After all, the greatest happiness is to see your children happy and healthy!
There are several theories to explain the reason for the ability of balloons to fly. In a broad sense, this process is determined by the ratio of the weight of air and gas. If the balloon is full...
There are several theories to explain the reason for the ability of balloons to fly. In a broad sense, this process is determined by the ratio of the weight of air and gas. If a balloon is filled with gas, it rises up and does not fall to the ground. When it is filled with air, for example, when a person inflates a balloon on his own, its ability to fly is reduced. The gas is much lighter than air, which is why balloons filled with helium float best.
Depending on the filling, balloons can perform different manipulations:
- if the ball is filled with carbon dioxide, air or argon, then it will fly worse;
- neon, methane, nitrogen, helium and hydrogen make the ball take off rapidly due to the minimal weight of these gases and the large difference with the mass of air.
Balloon flight from a physics point of view
From the point of view of physics, any body placed in a gas or liquid is subject to a displacement force equal to the weight of the body. The balloon in this case is a body “placed” in the air. Because When the gas filling the ball makes it light compared to air, buoyancy begins to occur. Due to this, the ball quickly rises up and begins to fly.
With the help of physics, it is possible to explain the reason for the not very good flying properties of balloons filled with air. The weight in this case is almost the same, so the ball can only float in the air, but without force it sinks to the ground.
The flight of a balloon in the air is comparable to the sailing of ships on water. In both the first and second cases, the lighter body is pushed out by heavy water or air. Moreover, water and air have almost equal buoyancy abilities.
Why do hot air balloons fly?
Large balloons intended for aeronautics fly for the same reasons as small toy balloons. The explanation for the ability to fly in this case is also the laws of physics. The size of the ball, the weight of the basket and the passengers are closely related to each other. The balloon rises by heating the air in it and the resulting gas. Due to this effect, the ball becomes lighter than air and a buoyant force is exerted on it. 
Balloon control
It is impossible to control any balloons. Home control force always air or wind. If you let go of a small balloon and hold it by the thread, then, despite your efforts, you will not be able to turn it in the desired direction. A similar situation occurs with balloons. The only thing passengers in the basket can do is lower the ball to ground level or lift it higher into the air. The height is gained by reducing the weight (special weights are dropped), and the ball is lowered by reducing the amount of gas by controlling the heating temperature of the air inside the rubberized material. The temperature is changed by changing the burner level.
Why are balloons and airships filled with hydrogen or helium?
As a child, everyone played with balloons. No one has ever wondered why balloons are filled with hydrogen or helium. To answer this question, you should remember some questions from the school physics course. 
A little physics
If a body is in the air, several forces act on it. Greatest influence exert Archimedean force and weight. Their difference is called lift. If they are equal, then the balloon hangs freely or moves through the air in intricate curves, the shape of which depends on the currents. If the Archimedean force is greater than the weight, a lifting force arises, acting upward on the balloon. 
The weight of the aircraft consists of the gas itself, the shell in which it is located, and the load being lifted.
If you fill the shell with ordinary air at a temperature environment, the ball will not rise. The air needs to be heated. Therefore, the balloon must be equipped with a burner to constantly heat the air inside the shell.
The Archimedean force depends on the volume of the shell and the difference in densities of the air and gas contained in it.
With increasing altitude, the temperature decreases, air pressure and its density in a closed shell decrease. Accordingly, the Archimedean force decreases, and the ball begins to descend. To prevent this from happening, a hole is made in the lower part of the shell, under which the burner is placed. By decreasing or increasing the amount of fuel burned, you can control the flight altitude.
IN aircraft with a closed shell, gases are used that, at the same temperature, have a density less than the surrounding air.
Among the available gases, hydrogen has the lowest density. In industry it is produced in large quantities, so its cost is relatively low.
Today, for safety reasons, the spherical shell of a balloon is filled with helium. This rare chemical element was first discovered through spectral analysis of the sun and was given its name Helios, which means solar. Much later, this gas was discovered on earth.
At the same temperature, the density of helium is 10 times less than air. Hydrogen has an even better indicator - 20. Therefore, initially the balloons were filled with hydrogen. But, unlike helium, it is a flammable and explosive gas. This element is safe to use, but a helium-filled balloon has much less lift.
A little history
Large balloons are called aerostats, and in the past they were mainly intended for scientific research. Most of them were spheres of various diameters.
The largest balloon, Record, with a sphere volume of more than 4000 m³, took off in the fall of 2010. 36 people traveled in its gondola.
The maximum altitude to which the balloon rose was more than 21 km. The record flight was made by Indian citizen Vijaypat Singhania in 2005. The balloon was filled with warm air.
Cigar-shaped airships were used to transport people and cargo at the beginning and middle of the last century.
The largest airship in human history, the Hindenburg, was constructed in Nazi Germany in the late 30s. He made 21 flights across the Atlantic and died in 1937. At that time there was no helium in Germany and all Hindenburg tanks were filled with hydrogen. The cause of the accident is unknown. After the tragedy, hydrogen-filled balloons and airships are no longer used to transport passengers. They are used only for scientific purposes.
What are the stages of preparation for a hot air balloon flight?
Pre-flight preparation
For a safe hot air balloon flight, you must check the weather conditions and select a suitable starting point for takeoff. The current and forecast weather must provide the pilot with the necessary visibility to be able to see and avoid obstacles (fog or low clouds), the wind must be light enough to allow takeoff and landing (less than 8-16 km/h depending on skill level) and experience of the pilot, passengers, crew and ground crew).
The starting point (take-off area) must be large enough to allow the balloon envelope to unfold and inflate without obstructions in the direction of the wind such as power lines, trees and buildings. Finally, the starting point must be positioned so that the predicted wind flow guides the balloon to a suitable landing site. There should be no bodies of water, large urban areas or forests in the balloon landing zone; it is not safe to fly over obstacles without sufficient fuel.
Before starting, hot air is pumped into it using propane-powered burners.
To do this, the balloon shell is laid out on the ground and attached to the basket and burner. A fan, often gasoline-powered, is used to force cool outside air into the enclosure. Cold air partially inflates the ball until it reaches its basic shape, allowing it to start the burner to heat the air. Once the balloon is in a vertical position, the pilot and passengers climb into the basket. When the pilot is ready to launch, he applies more heat through the balloon burner and the balloon lifts off...
The ground crew stows equipment and follows the direction of the balloon's flight to the landing site.
Balloon flight.
Requires certain pilot skills to control balloon- rise or descend in air currents. Thus, it is important for the pilot to determine at altitudes other than the balloon's altitude which direction the wind is blowing. To control this, the pilot uses various methods. This includes using visual cues such as flags on flagpoles, smoke from chimneys, etc. To determine the direction of the wind over the balloon, the pilot uses pre-flight weather forecast data, which includes a forecast of air flow at upper layers. Data is also obtained experimentally by launching helium balloons, known as weather balloon, before the start, to get information about where the wind is actually blowing. Another way to determine the actual direction of the wind is the movement of other balloons whose diameter is larger size weather balloon.
Balloon flight control
The direction of the balloon's flight depends on the wind, but the balloon's flight altitude can be adjusted by changing the temperature of the air inside the shell. The pilot can operate one or more burner valves to increase the temperature inside the balloon's shell, thereby controlling lift to allow the balloon to rise or fall or even stop. The pilot can also open the balloon's vent valves if the shell is equipped with one, thereby lowering the temperature inside the shell to descend or slow or even stop the ascent. If the pilot does not intervene, the air inside the shell will slowly cool.
Slow response
One of the tricks involved is learning to deal with latency. To slow down or stop the descent, experimental experience in opening the burner valve is required. The action of the burner lightens the overall weight of the balloon system and increases its buoyancy, but not immediately. It may take 30 seconds or more from the time the burner is running to slow down or stop, depending on the rate of descent of the ball, depending on the cooling of the air in the ball, or how hard the burner was working. This delay requires a lot of knowledge on the part of the pilot.
Third class
The ability to change direction of flight at altitude is called third class. In the northern hemisphere, air currents at altitude move in a spiral, when viewed from above, from high pressure levels and counterclockwise to the level low pressure. But when flying close to the ground, the ball will tend to move in a straighter direction. Thus, the pilot must find a left turn during the descent to landing. In the southern hemisphere, the direction of the spiral is exactly the opposite. In fact, interaction with uneven terrain may reduce or eliminate these phenomena.
Level flight
The burner is designed to create enough heated air to quickly lift the ball. It is only more effective when it is wide open.
But when the balloon is not actively heating up, it is cooling. This means that it is in perfect balance for only a moment. The rest of the time it is either heated or the air in it is cooled.
These two facts enable the pilot to use the burner at intervals of a few seconds to keep the balloon drifting slowly up and down at the desired altitude.
An exception is made when flying at low altitudes, as well as when landing. The torch can be used in very short bursts at significantly high frequencies, thereby sacrificing efficiency and accuracy.
Transport
Typical vehicles are jeeps with equipment trailers.
While it is certainly possible to enjoy the sport without being chased by car, by walking or biking to the landing site, many balloonists prefer to follow the chase by car. During landing, the transport crew can help: with disembarkation, catch ropes when landing the ball in cramped circumstances; help with packing equipment.
The connection between the ball and vehicle carried out using two-way radio communication, mobile phones, or even screaming when he's close enough.
Landing
Most pilots try to land as softly as possible. This becomes a difficult task if the wind speed at ground level is more than 8 km/h or so. If the ball is moving at this speed or more when it makes contact with the ground, the basket (which usually does not have wheels or any other kind of bottom) may drag along the ground or even tip over. Even the crew present on the ground cannot provide sufficient assistance. Total weight(for an average passenger balloon system) can easily exceed the weight of a car (it's best not to stand on the landing side of the balloon to avoid being between a rock and a hard place). Pilots can improve landings by landing in areas protected from the wind, such as behind a tree line or in a small valley.
Every adult has, deep down in their soul, a memory of a bright balloon bursting into the sky. This is probably why even now a gifted balloon gives a good mood and a smile.
A balloon is an indispensable attribute of birthdays, weddings and any other celebrations. And children's party It is absolutely impossible to imagine without him. What is its magic? Maybe in his striving upward, in the ease with which he rises to the sky?
Balloon magic
Modern balloons that can fly are filled with gas. Its density is significantly less than that of air, which allows it to fly higher and higher. The gas, which has a lower density, fills the internal space of the ball and is acted upon by the buoyant force of the air.
The most ordinary balloons can be inflated with your mouth. But such balls cannot fly upward, since the density of carbon dioxide exhaled by a person is lower than the density of air. They require wind to fly. But light gas allows the ball to rush upward on its own.
How the ball learned to fly
The history of the appearance of hot air balloons goes back hundreds of years. There are references to bags made of bull leather tanned by Karelian craftsmen, filled with warm gas, with the help of which they moved over short distances. These evidences date back to the 12th century, but scientists have not found precise evidence of their truth.
And here is a documented chronicle of the birth of balloons:
- The great-grandfathers of balloons were the results of Michael Faraday's experiment, as a result of which he created rubber bags filled with hydrogen. It was they who began to be used as holiday decorations, flying in the air to the delight of people.
- A year later, do-it-yourself kits appeared on sale, consisting of a tube of liquid rubber and a can of gas. The children received their first inflatable toys.
- In 1922, a misfortune occurred, which, however, contributed to the development of the “ball” industry. During a city celebration, balloons filled with hydrogen exploded. Since then, the use of dangerous flammable gas has been stopped and absolutely safe helium has been added to the entertainment.
- 1931 was the year of birth of latex balloons. Now you can create balls various shapes to the delight of the children.
Nowadays, balloons are produced not only from latex, but also from foil - in various shapes and sizes. Helium or a mixture of helium and air is used for inflation, which guarantees complete safety and gives the balloons the ability to fly far into the sky.
