Research work "mystery of the balloon". Why do balloons fly? Why does the balloon take off

Balloons rise up because the gas that fills them is lighter than the surrounding air. Many gases, in particular hydrogen and helium, have a lower density than air. This means that at a given temperature they have less mass per unit volume than air.

When such light gases are pumped into a balloon, it will rise until the total weight of the gas envelope, basket, weight, and cables is less than the weight of the air displaced by the balloon. (Because air is considered in physics like a liquid medium, the same law applies here as for bodies immersed in a liquid.) Hot air, which has a lower density than cold air, also rises. Although hot air is not as light as some gases, it is safer and more easily produced by propane burners mounted under the neck of the balloon's shell, which is usually made of lightweight fabric such as reinforced nylon. Hot-air balloons usually stay in flight for several hours, but without additional heating of the air inside the envelope, they will gradually lose altitude.

Molecules at different temperatures

• When the air is cold, the molecules move slowly and are close to each other.
• When the air warms up,molecules begin to move faster and diverge to the sides, filling a larger volume.
• Since the heated aircontinues to expand, it becomes less dense.
• When the air is cooledmolecules lose their speed, volume decreases and density increases.

1. The balloon lies on its side. Propane burners heat the air inside the shell, which causes it to inflate and rise up.
2. Hot, light air (picture below the text) rises inside the shell and then flows down along its walls. Cold air is squeezed out through the neck, the weight of the shell with air decreases and the balloon rises.
3. Pilots maintain or increase flight altitude by periodically turning on the burners. As long as the air inside the shell is hotter than the outside, the lifting force overcomes the force of attraction.
4. The balloon descends as the air that fills it cools and contracts. Pilots can accelerate their descent by venting hot air through a hole in the top of the balloon.

Interaction of pressure, volume and temperature

Interdependence of three parameters. The pressure, volume and temperature of a gas are interrelated. At room temperature (near figure on the right), the movement of gas molecules inside the vessel creates a certain pressure. If the volume is > less than half (middle figure on the right), the internal pressure doubles. When air is heated (far right), its pressure increases and its volume increases in proportion to the increase in temperature.

Civil aviation once began with balloons: before airplanes and helicopters, it was like walking to the moon, and people began to fly on balloons back in the 18th century. Today we will tell you how it happens on the 21st: I went to Cappadocia - a region in central Turkey - where mass flights are carried out almost every day; balloons in the air - several dozen at the same time, and passengers, respectively, several hundred.

A little physics. How a hot air balloon flies

A modern passenger balloon is correctly called a hot air balloon, or a hot air balloon - by the name of the Montgolfier brothers, who in 1783 made the first flight on an aircraft of this type. As part of import substitution, the story has become popular that in fact the first hot air balloon was built half a century before by the Russian inventor Kryakutnoy, but this is just a hoax created after the French flight and promoted in Soviet times.

The principle of flight of a hot air balloon is very simple: inside its shell there is air whose temperature is higher than the temperature of the surrounding air. Since the density of warm air is lower, it, according to the law of Archimedes, tends upward under the action of a buoyant force. At the same time, the shell itself and the payload are attracted to the Earth (the shell is approximately 25x15 m in size with a basket and all equipment weighs 400-500 kg, plus passengers: there were twenty people in our basket). The equality of these forces allows the balloon to "hover" in the air at a certain height.

How a balloon is flown

The main control element of a hot air balloon is a gas burner located under the shell and directed upwards. It burns a mixture of propane and butane, which is taken on board in cylinders similar to those that many summer residents have in the kitchen. With the help of fire, the air in the shell is heated; the temperature rises, the ball rises. Depending on the volume of the shell (2-5 thousand cubic meters of air), payload and ambient temperature, the temperature inside is 50-130 degrees Celsius. The air in the shell is constantly cooling down and the ball begins to decline, so you need to periodically “turn on the heat” to maintain a constant height. In general, everything is simple: more fire - we rise, less fire - we maintain altitude, little-little-little-little-little fire - we descend.

However, in order to descend, you can not wait until the air cools down: in the upper part of the shell there is a valve that can be opened and closed with ropes. If you open it, some of the warm air will come out and the ball will fly down.

They take at least two gas cylinders with them (one main, the other spare) - this is enough for about one hour of flight, a variometer for measuring vertical speed and a walkie-talkie for communicating with pilots of other balls and escort vehicles (more on them below). And, most importantly, there are no sandbags. They are used as ballast on gas balloons (with helium and other similar gases inside), and a hot air balloon is not needed.

The top valve is open, the balloon is deflating. Pay attention to the number. In Turkey, balloons are registered as TC-Bxx, for example, TC-BUM. In Russia, they are registered in the General Aviation Register and have numbers RA-xxxxG. Each balloon has a certificate of airworthiness, everything is as it should be.

Where is the balloon going?

We can only control the vertical speed of the balloon. It flies horizontally wherever the wind takes it. That is why the balloon is unsuitable as a full-fledged vehicle: it is still a pleasure aircraft. Despite this, flights on balloons are regulated by the aviation authorities no less than on airplanes. Each balloon has a registration in the aircraft register and a corresponding number on board, and pilots (there are two of them) - a license. Flights are carried out according to the rules of visual flights, that is, with good visibility, the absence of strong wind is also a prerequisite. The problem is that you can only fly early in the morning at dawn or, conversely, at sunset: during the day, ascending air currents from the earth’s surface heated by the sun make flights unsafe (and there are up and down flows in the morning, just not so strong). So you can easily run into a situation where you arrived, but did not fly anywhere - plan just in case for several days at once!

Each balloon has its own escort vehicle: a jeep with a flatbed trailer the size of a basket. Jeep - because the ball will land, most likely not on the road. Aerobatics is landing directly on the platform; much cooler than putting a fighter on an aircraft carrier.

If the balls collide with each other in the air, then ... nothing happens, they just repel each other and fly further. In general, it is quite difficult for the balls to collide: after all, the wind carries them in the same direction.

How is a hot air balloon flight

First, you are brought to your hot air balloon. At this moment, he is still lying on the ground, the basket is on its side, and with the help of a powerful fan, the shell is filled with air, while simultaneously heating it with a burner. At some point, the limp ball becomes elastic and soars up. The basket is turned over, passengers sit in it, climbing over the side. Inside there are two-point harnesses, which, however, few people use, as well as ropes that you will need to hold on to when landing. The pre-flight briefing, in fact, lies in the fact that when landing, you must definitely sit down and hold on to the ropes, since there is a high probability of the basket tipping over: this will avoid injury.

Flight preparation

The pilot gives more fire, and ... the ball soars smoothly up and to the side. It feels like riding a Ferris wheel, only much higher. And at the same time, there is no noise or vibration, so even seasoned aerophobes are not afraid. And even those who are afraid of heights (and the balloon rises to 1500 m with an average flight altitude of about 500) are not afraid: because of the high (about 1.5 meters) side of the basket, it is impossible to fall out of it, and standing posture provokes to look not down, but to the sides. Indescribable beauty! The real Tatooine! Turkish pilots try to fly in such a way as to get closer to the rocks, "chimneys" and give them the opportunity to see them, descend almost to the roofs of the houses of ancient villages - of course, everything can be photographed and filmed, the main thing is not to drop the camera.

Flight altitude reaches 1500 m

By the way, there is no wind at a height - or rather, it is not felt, because you are flying along with this very wind!

How to fly in a hot air balloon

Cappadocia, as you already understood, is a place where balloon flights are a developed and popular form of recreation. You will need to get to the city of Urgup, which is 70 km from Kayseri, where the nearest civil airport (ASR) is located. There are several daily flights to Kayseri from Istanbul (IST and SAW) by local airlines: Turkish Airlines, Anadolujet, Pegasus Airlines, etc. The flight takes about an hour and a half. Of course, many different airlines fly to Istanbul itself - from Aeroflot and Turkish Airlines to Onur Air and Pobeda. Buying two separate tickets to Istanbul and to Kayseri can help you save a lot (and at the same time spend a couple of days in Istanbul).

Low pass over the mountain - one of the aerobatics in balloons

There are more than a dozen airlines with balloons in Urgup; You can also purchase a flight through their Russian partners by simply typing the appropriate request on Google - it’s convenient if you don’t know Turkish and want to plan everything in advance, or you can directly at the hotel in Urgup, but everything depends on the hotel. Be guided by the fact that the cost of an hour-long flight is 13,000 rubles per person, including transfer from your hotel and back and a modest breakfast in the immediate vicinity of the starting point (tea, coffee, buns).

Video (pre-flight briefing, low-altitude passage, landing on an aircraft carrier, balloon cleaning).

There are several theories to explain the reason for the ability of balloons to fly. In a broad sense, this process is due to 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 due to the ratio of the weight of air and gas. If the balloon is filled with gas, then it rises and does not fall to the ground. When it is filled with air, for example, when a person inflates a balloon on his own, his ability to fly is reduced. The gas is much lighter than air, which is why balloons filled with helium fly best.

Depending on the filling, balloons can perform different manipulations.:

• if the balloon 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 minimum weight of these gases and the large difference with the mass of air.

Balloon flight from the point of view of physics

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 the gas filling the balloon makes it lighter than the air, then a buoyant force begins to be exerted. Due to this, the ball quickly rises up and begins to fly.

With the help of physics, one can also 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 hover in the air, but without force, it falls to the ground.

The flight of a balloon in the air is comparable to the navigation 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 possess almost the same degree of buoyancy.

Why balloons fly

Large balloons designed 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 in close relationship with each other. The ball rises by heating the air in it and the resulting gas. Due to this impact, the ball becomes lighter than air and a buoyant force is exerted on it.

Balloon control

It is impossible to control any balloons. The main driving force is always air or wind. If you let go of a small balloon and hold it by the thread, then, despite efforts, you will not be able to turn it in the right direction. A similar situation occurs with balls for aeronautics. The only thing passengers in the basket can do is lower the balloon to ground level or lift it higher into the air. Height is gained by reducing weight (special weights are dropped), and the ball is reduced by reducing the amount of gas by controlling the temperature of heating 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 children, everyone played with balloons. No one wondered why balloons are filled with hydrogen or helium. To answer this question, we should recall some questions from the school physics course.

A bit of physics

If the body is in the air, several forces act on it. The Archimedean force and weight have the greatest influence. 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, there is a lifting force acting on the balloon upwards.

The weight of the aircraft is made up of the gas itself, the shell in which it is located, and the load being lifted.

If the shell is filled with ordinary air at ambient temperature, the balloon will not rise. The air needs to be heated. Therefore, the balloon must be equipped with a burner for constant heating of the air inside the shell.

The Archimedean force depends on the volume of the shell and the difference between the densities of the air and the gas in it.

As the altitude increases, the temperature decreases, the air pressure and its density in the 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 a burner is placed. By decreasing or increasing the amount of fuel burned, you can control the flight altitude.

Closed-shell aircraft use gases that, at the same temperature, have a density less than that of the surrounding air.

Among the available gases, hydrogen has the lowest density. In industry, it is produced in large volumes, so its cost is relatively small.

Today, for safety reasons, the spherical shell of the balloon is filled with helium. This rare chemical element was first discovered using spectral analysis on 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 balls were filled with hydrogen. But, unlike helium, it is a flammable and explosive gas. Using this element is safe, but a balloon filled with helium has much less lift.

A bit of history

Large balloons are called aerostats, and in the past they were mainly used for scientific research. Most of them were spheres of various diameters.

The largest balloon with a sphere volume of more than 4000 m³ took off in the autumn of 2010. 36 people traveled in its gondola.

The maximum height to which the balloon has risen is more than 21 km. The record flight was made by Indian citizen Vijaypat Singhania in 2005. The balloon was filled with warm air.

At the beginning and middle of the last century, cigar-shaped airships were used to transport people and goods.

The largest airship in the history of mankind, the Hindenburg, was designed 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 the Hindenburg tanks were filled with hydrogen. The cause of the accident is unknown. After the tragedy, hydrogen-filled balloons and airships are not used to transport passengers. They are used for scientific purposes only.

The balloon has neither motors nor the rudder we are accustomed to. Of the entire technological arsenal - only burners, sandbags and a special valve in the upper part of the dome for air etching. How to control this aircraft?

From the history of aeronautics

The birth of balloons was the first real embodiment of the age-old dream of mankind to conquer the fifth ocean. In 1306, the French missionary Bassu first described how, while in China, he witnessed the flight of a balloon during the accession to the throne of Emperor Fo Kien.

However, the French town of Annone is considered the birthplace of aeronautics, where on June 5, 1783, the brothers Etienne and Joseph Montgolfier raised into the sky a spherical balloon created by them filled with heated air.

The flight of an aircraft weighing about 155 kg and a diameter of 3.5 meters lasted only 10 minutes. During this time, he covered about a kilometer at a 300-meter height, which was an outstanding event for his time. Later, balloons in honor of the creators began to be called hot air balloons.

The balloon of the Montgolfier brothers consisted of a linen shell covered with paper. To fill it with hot air, a fire was made from finely chopped straw. And 3 months later, an addition was made to the design of the aircraft in the form of a special basket for passengers.

Modern balloons are undoubtedly more perfect, but they are made in almost the same way. For the manufacture of the spherical shell of the ball, a special thin and durable polyester material is used. The air heating system has changed. The function of the fire is performed by an adjustable propane gas burner installed in a basket directly under the dome.

Despite being heavily dependent on the wind, modern hot air balloons are manageable. The flight height is adjusted by an outlet at the top of the canopy with a break cord. A side valve is provided to change course. There are also more complex designs, where another one filled with helium can be placed inside the main dome.

How to fly a balloon with a basket

Balloon control is an activity that requires serious preparation and considerable financial costs. Suffice it to say that a balloon pilot training course today costs about 200,000 rubles. The price of the balloon itself (depending on the model) is commensurate with the price of a car.

Training

The flight is preceded by careful preparation. First of all, it is necessary to study the weather conditions - cloudiness, visibility and wind speed. In accordance with the received data, the flight route is planned. Due to unforeseen changes in weather conditions, it is precisely such a route that is chosen where there are enough places on the way for safe landings.

Takeoff

In order for the balloon to take off, the efforts of the entire crew are necessary. The best option for a starting point is a flat area 50 x 50 meters in an open field, where there are no extraneous objects nearby - poles, trees, power lines.

Then the assembly of the ball begins: burners are attached to the basket, which are connected with special hoses to gas cylinders. After a test run of the burner, the crew proceeds to stretch the canopy (necessarily in the direction of the wind). Further, the stretched dome is fastened to the basket with special carabiners.

The next step is to fill the dome with cold air using a fan, after which the burner is started to heat the air. The heated air lifts the dome from the ground, and the crew (with passengers) takes their places. To prevent the ball from flying away, it is first tied to the car.

Flight

Despite the lack of a motor and wings, the balloon is controllable, which requires certain skills. The main controls are the burners and the exhaust valve. To climb, the burner turns on and the air heats up additionally, and to descend, the valve opens slightly. Horizontal flight occurs due to a tailwind. This is where the skill of the pilot comes into play. So, in order to fly faster, he can increase the flight altitude where the wind speed is stronger.

Descent

The landing site is chosen in advance. It must be large and secure. The ideal option is a football field next to the highway. The crew reports the landing site by radio to the ground. Next, the pilot releases air from the dome using a valve. The ball slowly falls to the ground.

Chernyshova Ekaterina, student 1 "A" class MBOU secondary school No. 18

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Slides captions:

Project on the topic: "Why does a balloon fly?" Completed by: student of grade 1 "A" MBOU secondary school No. 18 Chernyshova Ekaterina Aleksandrovna Supervisor: Didenko Olga Nailevna

Relevance: balloons can be found at any holiday Purpose: to determine the reason why the balloon rises. Hypothesis: Different properties of the gas inside the balloon and the air outside push the balloon up.

The tasks are to find out what substance the balloon is filled with; consider the concept of density through mass; explore the density of substances available in the house using various methods. Methods and methods: experiments in accessible conditions.

The balloon was filled with helium. It takes off because the density of helium is less than the density of air (the condition for bodies to float).

Density shows how much of a substance is contained in a unit of volume. The greater the mass, the greater the density of the substance. ρ (ro) - kg/m³

Mass of water – Mw Mass of oil – Mm Mw > Mm => ρw > ρm Density of water – ρw Density of water – ρm Mw =114 g Mm=108 g

ρ in > ρ m

Based on the condition of floating bodies ρ d - the density of the tree from which the cube is made ρ in > ρ d

Conclusion: a balloon filled with helium tends to rise, since its density is less than the density of air. I proved by density determination that the density of oil is less than the density of water. She also conducted experiments and compared the density of various available substances.