Balloon

Background

A balloon is an air-tight bag made out of a light material that can be inflated with air or gas. Toy balloons are available in all kinds of shapes, sizes, and colors to delight children and adults at birthday parties and other festive occasions.

Balloons were first invented in France in the late 18th century. Two papermakers, Jacques and Joseph Montgolfier, discovered that when paper bags are filled with hot air, the bags rise. Quick to realize the potential of this, they began experimenting with balloons of various materials such as paper, cloth, and silk. They made the first public demonstration of a lighter-than-air balloon in June 1783, with a 35-foot (11 m) diameter balloon made of cloth lined with paper. Later that year, Jacques Charles flew a balloon made of silk coated with a rubber varnish and filled with hydrogen, a gas that is lighter than air. These early demonstrations attracted a great deal of excitement, and balloons were soon put to many uses in science, sport, and war.

The rubber toy balloon as we know it today is different from the early balloons in that it is made entirely of rubber. A practical way of making such formed rubber products required several discoveries and inventions. These developments took place gradually over the years since the first rubber factory in the world was established near Paris in 1803.

Natural latex is a mixture of small globules of rubber substance suspended in water (much like milk). When it is exposed to air, heat, or certain chemicals, it coagulates or clots together. The globules of rubber lump together and separate from the watery portion of the latex, eventually forming an elastic, solid material. To improve its strength, resilience, and resistance to hot and cold temperatures, rubber is vulcanized or cured by various methods, such as mixing with certain chemicals or treating with heat.

The idea of making a product out of rubber is an old one. The natives of South America created bottles and other articles by coating molds made of earth long before Europeans began experimenting with rubber in the mid-1700s. In 1830, the Englishman Thomas Hancock patented a process for creating products by pouring latex over molds or dipping molds into a latex mixture—the forerunner of the modern technique of producing dipped products such as rubber gloves and condoms.

In 1921, a method of retarding the coagulation of liquid latex was developed. This method enabled rubber makers to transport raw latex in a liquid form more easily to manufacturing centers around the world. This in turn led to new processes for making rubber goods. In the early 1920s, a number of patents were granted in England for processes that allowed molds to be dipped in liquid latex. In 1931, the first modern latex balloon was created by Neil Tillotson in his attic. He sold 15 of his "Tilly Cat" balloons (shaped like a cat's head, complete with whiskers printed on with dye) for the Patriot's Day parade in Massachusetts in April 1931, and formed a company that still makes balloons today.

Raw Materials

Although rubber can be made synthetically, natural latex is preferred for its great elasticity. It can be stretched to seven or eight times its original length and still return to its former shape. Synthetic rubber has not proven to be as elastic and resilient as natural latex.

Raw, natural latex is a white or yellowish opaque liquid, similar in appearance to milk. Latex is the secretion of certain plants, in particular the Hevea tree originally found in Brazil. The most important sources of natural rubber today are plantations in Malaysia and Africa.

Producers of rubber must harvest the raw material from these trees, which involves scoring the trees with shallow cuts and letting the sap ooze from the cuts into buckets. The latex is collected in large containers, filtered to remove foreign particles, and mixed with alkali to prevent coagulation. It is then shipped in liquid form to processing centers in different parts of the world.

Latex must be mixed with additives before it can be used in industrial processes. Certain chemicals are mixed in to achieve a desired thickness, rate of drying, and other properties. Other chemicals (collectively known as antidegradants) are added to slow the oxidation and decomposition of the rubber. To give it color, pigments are mixed into the latex. The pigments may be fine metal oxide powders or organic dyes.

The Manufacturing
Process

In essence, the process of making a toy balloon involves dipping a mold into liquid latex. The mold, or form, is shaped like a deflated balloon.

The earliest balloon forms were disposable, made from cardboard attached to dowels. Modern forms are reusable and usually made from stainless steel, aluminum, or porcelain. The forms must be smooth and polished. A number of such forms are attached upside down to a board or rack. The boards are moved mechanically from one station to another in the factory.

To be efficient in terms of cost and number of balloons produced, balloon manufacture has become a highly automated, continuous loop process. Balloons are made in batches, all of the same color and size, since changing the color and form is time-consuming and requires manual intervention. Manual intervention is usually only needed for setting up a run and then later for packaging the finished product, and for dealing with occasional mechanical problems that may arise.

Preparing the latex

• 1 Prior to its use, the latex may need to be colored. This involves mixing a pigment into the latex. It may be done at the balloon factory, or the balloon maker may purchase already-pigmented latex from a supplier.
• 2 The latex must be poured into tanks into which the forms will be dipped. The tanks are kept at a certain temperature and may include stirring mechanisms to keep the latex circulating to avoid settling.

Dipping the forms

• 3 The balloon forms are first heated, then immersed in a tank of coagulant solution for a few seconds. When the forms are immersed in the liquid latex, the coagulant will cause the rubber to gel in a thin sheet around the forms. A commonly used coagulant solution is a mixture of water, a calcium-based salt, soap, and talc powder. The salt is the actual coagulant; the soap helps the latex spread in an even film, and the talc helps ease the removal of the rubber from the forms in a later step.
• 4 The forms are heated to a temperature between 100°F (38°C) and 200°F (93°C), and then immersed in a tank of colored latex. The coagulant causes the latex to coat the forms. The longer the forms are left in the tank, the thicker the coating that sticks to them. For balloons, a very thin layer of latex is desired, so the forms are immersed only for a few seconds. The forms must be inserted and removed at carefully controlled speeds to avoid trapping air bubbles and to achieve an even, thin coating.

Making the ring

• 5 A lip is formed on the neck of the balloon by rolling the edges of the rubber using brushes or rollers. This creates the ring seen around the opening of the balloon.

Removing excess coagulant

• 6 Next, the forms are immersed in a tank of leaching solution (often plain water) to dissolve and leach away excess coagulant from the rubber.

Curing the rubber

• 7 The rubber on the forms must be dried and cured. The method used varies among manufacturers. Some balloon makers use a latex that already contains a vulcanizing agent, in which case the rubber is dried at a moderate temperature. Other makers induce vulcanization by putting the rubber-coated forms into an oven and curing for as long as an hour.

Removing the balloons

• 8 The balloons are then mechanically removed from their forms. One approach is to blow them off using a spray of water or air and collecting the balloons in a basket or net.
• 9 If the balloons are removed using a spray of water, they are next placed in a centrifuge, where excess water is removed by spinning the balloons around at high speed.
• 10 The balloons are then dried in large tumble dryers.

Printing and packaging

• 11 Next, the balloons may either be packaged, or first printed and then packaged. If they are packaged directly, they are moved on a conveyor belt past a counting device and placed into bags. When an appropriate number of balloons has been placed in each bag, the bags are sealed.
• 12 Printing designs on balloons, such as logos or faces, actually involves several steps. First, the balloons must be inflated in order to allow even printing. This requires a worker to manually place each balloon on the inflating device. Next, a pattern is carefully printed on each balloon. Finally, the balloons are removed and passed on to the packaging stage.

Quality Control

The balloon manufacturing environment must be strictly controlled in order to achieve high quality and consistency. Throughout the manufacturing process, computer-based instrumentation records and controls air humidity, air temperature, latex tank temperature, the temperature in the ovens, dryers, and other parameters.

The latex and other chemicals used in the process must be carefully formulated for specific properties, and carefully maintained. For example, the latex must have certain viscosity and speed of drying. The tanks in which it is held must have devices to keep the latex circulating to avoid forming a "skin," and to prevent ingredients from settling.

Byproducts/Waste

It is in the manufacturers' best interests to waste as little rubber as possible because the cost of latex is high compared to the selling price of individual balloons. Balloon makers also reclaim much of the coagulant that ends up in the leaching solution. Unfortunately, what is not reclaimed ends up as liquid waste in the environment. The amount of chemical waste that can be released by a factory is regulated by government laws. Balloons also result in some waste after they are manufactured because they are invariably thrown away after they deflate or pop. However, because latex is natural, it eventually breaks down into other substances.

Safety Concerns

Toy balloons can be a source of joy, but they can also be unexpectedly hazardous. Young children have been known to die from accidentally choking on balloons. Latex balloons may also end up in water, where they eventually lose their color and can resemble jellyfish. Sea animals such as whales and turtles have attempted to eat them and have died because the latex clogs their digestive systems.

The Future

The toy balloon industry is very competitive. Manufacturers are constantly looking for ways to make the process more automatic and efficient, especially by reducing manual intervention. Currently the most labor-intensive portions are the printing and packaging steps. Increasing automation in these steps is an area for potential future improvement.

In recent years balloons made of metal films have become popular. The manufacturing process of these balloons is very different. They are made from a sandwich of two swatches of mylar—a polyester film—often circular in shape, which are sealed together around the edges. A small opening is left through which the balloon may be inflated. Because the material is initially flat, these balloons can be printed more easily than balloons made of rubber. The foil can be made very shiny and reflective, allowing for very bright designs. They are stronger and more durable than rubber balloons, but for some uses, this is also a disadvantage. For example, they cannot be twisted into various shapes nor can they be filled with water. The foil also takes much longer to degrade in the environment than rubber.

Where To Learn More

Books

Barlow, Fred W. Rubber Compounding: Principles, Materials, and Techniques. Marcel Dekker, Inc. 1988.

Coates, Austin. The Commerce in Rubber: The First 250 Years. Oxford University Press, 1987.

Hofmann, Werner. Rubber Technology Handbook. Oxford University Press, 1989.

—Renee M. Rottner

Balloon

Balloons and the exploration of the unknown

Resources

A balloon is a nonsteerable aircraft consisting of a thin envelope inflated with any gas lighter than the surrounding air. The balloon rises from the ground similar to a gas bubble in a glass of soda. The physical principle underlying this ability to ascend is Archimedes’ law, according to which any immersed body is pushed upward by a force equal to the weight of the displaced fluid. If this force is greater than the weight of the body itself, the body rises. The lighter the balloon is in comparison with air of the same volume, the more load (envelope, people, instruments) it can lift. The approximate lifting capacity of some lighter-than-air gases in a 1,000 cubic meters (1,308 cubic yards) balloon at 32°F (0°C) is shown below (in pounds):

For example, a balloon filled with nitrogen possesses only about 1/30 of the lifting capacity of the same balloon filled with hydrogen. As a matter of fact, only hydrogen, helium, and hot air are of practical importance. Hydrogen, the lightest existing gas, would be ideal for the balloon inflation if it had not one serious demerit: inflammability. Helium is 7% less efficient than hydrogen, and is absolutely safe in usage, however, but it is not easily available and production is not cheap. Hot air is safe and easy to obtain, making it the most often used for common manned flights. But to get lifting power equal to even 40% of helium it must be heated to about 570°F (299°C).

There is always an element of uncertainty in a balloon flight. The ascensional force of a hot-air balloon is difficult to control, since it is very unstable, sharply reacting to any variations of the inside air temperature. Once airborne, it floats freely in air currents, giving its pilot the ability to regulate only vertical direction.

From the first flight of a smoke-filled bag launched by the Montgolfier brothers in Paris in 1783 until the first practical powered airplane in 1905, balloons and their later modifications, airships, remained the only means of aerial navigation. This period was full of exciting achievements of courageous aeronauts. The crossing of the English Channel (1785, by Blanchard, France, and Jeffries, USA), parachute descent from a balloon (1797, by Garnerin, France), the crossing of the Irish Sea (1817, by Windham Sadler, England), and the long-distance flight from London to Weilburg, Germany (1836, by Green, England), are a few of the milestones in the balloon’s early history.

The suitability of balloons for observation, espcially of inaccessible areas, was soon recognized. The first air force in the world was created by France in 1794, and by the end of the nineteenth century balloon corps, whose main function was reconnaissance, were common in European and American armies. With the introduction of a heavier-than-air craft military interest in balloons faded. However, the most challenging pioneering and scouting missions via balloons were yet to come.

Balloons and the exploration of the unknown

In 1863, the first truly high-altitude ascent was made by Glaisher and Coxwell in England. The flight was purely scientific, intended to observe and record the properties of the upper atmosphere. The explorers rose to over 33,000 feet (10,000 m), an altitude that almost cost them their lives. This outstanding attempt was followed by many others, and high-altitude scientific ascents continued until the early 1960s.

A specific layer of the atmosphere between 35,000 and 130,000 feet (11,000 and 40,000 m)—the stratosphere—became a particular challenge to human spirit and engineering. The mark of 72,395 feet (22,066 m), achieved by Stevens and Anderson in 1935, was not surpassed until twenty years later, when the United States resumed the manned stratosphere ballooning. The last flight in the series was made by Ross and Prather, who attained the altitude of 113,740 feet (34,467 m) in 1961. Technology that allowed human survival in extreme conditions became a germ of future space life-support systems.

The introduction of new lightweight and very strong plastic materials made it possible to build extremely big balloons able to take aloft huge pay-loads. Loaded with sophisticated instruments, such balloons began to carry out complex studies of the atmosphere, biomedical and geographical research, and astronomical observations.

Each day, thousands of balloons measure all possible characteristics of the atmosphere around the entire globe, contributing to the worldwide meteorological database. This information is needed to understand the laws of air-mass movement and for accurate weather forecasting.

Balloon astronomy makes observations in the clarity of the upper air, away from dust, water vapor, and smoke. Telescopes with a diameter of up to 3.3 feet (1 m) are placed on platforms, which are supported by mammoth balloons, as high as an eight-story building, at elevations of up to 66,000-120,000 feet (20,000-35,000 m).

The Russian mission to Venus in 1985 used two helium balloons to examine the motion of the Venutian atmosphere. For 46 hours, they floated above Venus with an attached package of scientific equipment that analyzed the environment and transmitted the information directly to Earth. In comparison, a landing module functioned for only 21 minutes.

See also Aerodynamics; Buoyancy, principle of.

Resources

BOOKS

The Cambridge Encyclopedia of Space. Cambridge University Press, 2002.

Curtis, A. R. Space Almanac. Arcsoft Publishers, 1990.

DeVorkin, D. H. Race to the Stratosphere. Springer-Verlag, 1989.

Jackson, D. D. The Aeronauts. Time-Life Books, Inc., 1980.

OTHER

Prints George. “Flights of Fancy” <http://www.printsgeorge.com/ArtEccles_Aeronauts3.htm> (accessed October 30, 2006).

U.S. Centennial of Flight Commission. “Balloons in the American Civil War” <http://www.centennialofflight.gov/essay/Lighter_than_air/Civil_War_balloons/LTA5.htm> (accessed October 30, 2006).

Elena V. Ryzhov

Balloon

A balloon is a type of aircraft consisting of a thin envelope filled with a gas less dense than the surrounding air. The envelope can be made of rubber, plastic, treated paper or cloth, or other material through which gases cannot seep. Ordinary party balloons are good models for most kinds of balloon. They are made of rubber that expands when air is blown into them. And the air from a person's breath used to inflate them is less dense than the surrounding air.

Balloon gases

A balloon rises in the air for the same reason that a cork floats in water. Just as a cork's density is less than the density of the surrounding water, so a balloon's density is less than the air around it. The lower-density object, then, is pushed upward by the surrounding higher-density medium.

It stands to reason, then, that the best gas to use in a balloon is the one with the lowest density: hydrogen. In fact, hydrogen was used in the construction of balloons for more than a century. But this gas has one serious drawback. It burns easily and, under the proper circumstances, can even explode. The tragic fire that destroyed the Hindenburg dirigible (airship) in 1937 occurred when lightning set fire to hydrogen gas inside it.

Because of hydrogen's flammability, the most popular gas for filling commercial balloons is helium, the second-least dense gas after hydrogen. Helium has 93 percent of the lifting capacity of hydrogen with none of its safety concerns. The problem is that helium is more expensive than is hydrogen. Still, balloons used for commercial and research purposes today almost always use helium as the lifting gas.

Another gas used in balloons is hot air. Hot air has the same chemical composition as ordinary air but, because of its temperature, is less dense that the air around it. Balloons used for sight-seeing and sport usually use hot air. The gondola (traveling compartment) below the balloon itself contains a heating unit that warms air and then pushes it up into the balloon.

Balloon guidance

Vertical (upward or downward) movement of a balloon is generally under human control. In a sight-seeing balloon, the operator can turn the heater on and off to produce more or less hot air. Changes in the amount of hot air make the balloon rise or fall. Vents in the balloon envelope also make it possible to control the amount of gas inside the balloon, therefore changing its vertical movement. The horizontal movement of a balloon is beyond human control, however. Once a balloon has left Earth's surface, its horizontal motion is dependent on wind currents.

History

Joseph (1740–1810) and Jacques Montgolfier (1745–1799) are considered the fathers of ballooning. In 1783, after a series of experiments, the brothers constructed a balloon large enough to carry two humans into the atmosphere, the first manned aircraft.

The suitability of balloons for making atmospheric observations soon became evident, and manned balloon trips soon became common. In 1804, for example, French physicist Joseph Louis Gay-Lussac (1778–1850) traveled to an altitude of 23,000 feet and collected a sample of air. He found that air at that altitude was identical to air at Earth's surface.

In his ascent, Gay-Lussac nearly reached the limits of manned balloon trips without special protection. In contrast, in 1863, two English scientists, James Glaisher and Henry Tracey Coxwell (1819–1900), traveled to a height of over 33,000 feet to study the properties of the upper atmosphere. At that height, the air is so thin that the two men nearly lost their lives.

The greatest of the early balloonists, however, was French meteorologist Léon Philippe Teisserenc de Bort (1855–1913). Over a three-year period between 1899 and 1902, de Bort launched 236 balloons with instruments designed to measure atmospheric conditions.

Scientists are now able to use life-support systems, such as those that are common in space flights, to travel to higher and higher reaches of the atmosphere. The current record is held by two Americans, Ross and Prather, who reached an altitude of 113,740 feet in 1961.

Applications of balloon flight

Balloons are used today primarily for two purposes: for collecting information needed for making weather forecasts and for scientific research. Weather balloons typically carry packages of instruments called radiosondes for measuring the temperature, pressure, density, and other

properties of air at some altitude. Each day, thousands of these radiosonde-carrying balloons (called balloonsondes) measure all possible characteristics of the atmosphere around the world. Meteorologists depend on this information for making short- and long-term weather forecasts.

Balloons are also used extensively for astronomical research. Their advantage is that they can take telescopes high enough into the atmosphere that they will not be affected by dust, water vapor, smoke, and other forms of air pollution. Telescopes with a diameter of up to three feet are placed on platforms which are supported by mammoth balloons as tall as eight-story buildings. These telescopes have been carried to altitudes of 120,000 feet.

The Russian mission to Venus in 1985 used two helium balloons to study the motion of the Venusian atmosphere. For 46 hours, they floated above Venus with an attached package of scientific equipment that analyzed the environment and transmitted information directly to Earth.

The success of balloons on Venus has raised the possibility of a similar mission to Mars. American scientists have designed a device consisting of a large hot-air balloon and a much smaller helium-filled balloon

joined to each other. During the day, the air balloon, heated by the Sun, would drift in the Martian atmosphere with a payload of instruments. At night, the air balloon would cool and descend to the ground, where it would stay, supported in the upright position by the smaller gas balloon. Thus, the same probe would perform the on-ground experiments at night and the atmospheric experiments during the day, traveling from one location to another.

[See also Aerodynamics; Aircraft; Buoyancy ]

Balloon

A balloon is a nonsteerable aircraft consisting of a thin envelope inflated with any gas lighter than the surrounding air. The balloon rises from the ground similar to a gas bubble in a glass of soda. The physical principle underlying this ability to ascend is Archimedes' law, according to which any immersed body is pushed upward by a force equal to the weight of the displaced fluid. If this force is greater than the weight of the body itself, the body rises. The lighter the balloon is in comparison with air of the same volume , the more load (envelope, people, instruments) it can lift. The approximate lifting capacity of some lighter-than-air gases in a 1000 cu m balloon at 32°F (0°C) is shown below (in pounds):

For example, a balloon filled with nitrogen possesses only about 1/30 of the lifting capacity of the same balloon filled with hydrogen . As a matter of fact, only hydrogen, helium, and hot air are of practical importance. Hydrogen, the lightest existing gas, would be ideal for the balloon inflation if it had not one serious demerit: inflammability. Helium is 7% less efficient than hydrogen. It is absolutely safe in usage, however, but it is not easily available and its production is not cheap. Hot air is safe and easy to obtain, making it the most often used for common manned flights. But to get from hot air a lifting power equal to at least 40% of that of helium it would be necessary to heat it to about 570°F (299°C). The ascensional force of a hot-air balloon is difficult to control, since it is very unstable, sharply reacting to any variations of the inside air temperature . There is always an element of uncertainty in the balloon flight. Once airborne, it floats freely in air currents, leaving a man the possibility to regulate only the vertical motion .

For 123 years, since the first flight of a bag filled with smoke publicly launched by the Montgolfier brothers in Paris in 1783 till the first flight of the practical powered airplane of the Wright brothers in 1905, a balloon and its later modification, an airship , remained the only means of aerial navigation. This period was full of exciting achievements of courageous aeronauts. The crossing of the English Channel (1785, by Blanchard, France and Jeffries, USA), the parachute descent from the balloon (1797, by Garnerin, France), the crossing of the Irish Sea (1817, by Windham Sadler, England), and the long-distance flight from London to Nassau (1836, by Green, England) are a few of the milestones in the balloon’s early history.

The suitability of balloons for making observations and for reaching inaccessible areas was soon generally recognized. The first air force in the world was created by France in 1794, and by the end of the nineteenth century balloon corps, whose main function was reconnaissance, were the common feature of European and American armies. With the introduction of a heavier-than-air craft military interest in balloons faded. However, the most challenging pioneering and scouting missions via balloons were yet to come.

Balloons and the exploration of the unknown

In 1863, the first remarkable high-altitude ascent was made by Glaisher and Coxwell in England. The purpose of this flight was purely a scientific one: to observe and record the properties of the upper atmosphere. The explorers rose to over 33,000 ft (10,000 m). The attempt almost cost them their lives, but fortunately they survived to describe the unique experience. This outstanding attempt was followed by many others, and high-altitude scientific ascents continued until the early 1960s. A specific layer of the atmosphere between 35,000 and 130,000 ft (11,000 and 40,000 m), which is called stratosphere, for some time became a new challenge to human spirit and engineering art. The mark of 72,395 ft (22,066 m), achieved by Stevens and Anderson in 1935, was a tremendous success for that time and was surpassed only twenty years later, when the United States resumed the manned stratosphere ballooning. The last in the series was the flight of Ross and Prather, who attained the altitude of 113,740 ft (34,467 m) in 1961. The technology developed to secure man's survival in extreme conditions became a germ of future space life-support systems.

The introduction of new lightweight and very strong plastic materials made it possible to build extremely big balloons able to take aloft huge payloads. Loaded with sophisticated instruments, such balloons began to carry out complex studies of the atmosphere, biomedical and geographical research, and astronomical observations.

Each day, thousands of balloons measure all possible characteristics of the atmosphere around the entire globe, contributing to the worldwide meteorological database. This information is needed for understanding the laws of air-mass movement and for accurate weather forecasting .

Balloon astronomy takes advantage of making observations in the clarity of the upper air, away from dust, water vapor, and smoke. Telescopes with a diameter of up to 3.3 ft (1 m) are placed on platforms, which are supported by mammoth balloons, as high as an eight-story building, at elevations of up to 66,000-120,000 ft (20,000-35,000 m).

The Russian mission to Venus in 1985 used two helium balloons to examine the motion of the Venusian atmosphere. For 46 hours, they floated above Venus with an attached package of scientific equipment that analyzed the environment and transmitted the information directly to Earth . For comparison, a landing module in the mission functioned for only 21 minutes.

The success of balloons on Venus may be possibly continued on Mars . To carry a multipurpose research probe above the Martian surface, American scientists suggested an original device consisting of a big hot-air balloon and a much smaller helium-filled balloon connected together. During the day, the air-balloon, heated by the sun , would drift in the Martian atmosphere with a payload of instruments. At night, the air-balloon would cool and descend to the ground, where it would stay, supported in the upright position by the smaller gas-balloon. Thus, the same probe would perform the on-ground experiments at night and the atmospheric experiments during the day, travelling from one location to another.

See also Aerodynamics; Buoyancy, principle of.

Resources

books

The Cambridge Encyclopedia of Space. Cambridge University Press, 2002.

Curtis, A. R. Space Almanac. Arcsoft Publishers, 1990.

DeVorkin, D. H. Race to the Stratosphere. Springer-Verlag, 1989.

Jackson, D. D. The Aeronauts. Time-Life Books, Inc., 1980.

Elena V. Ryzhov

bal·loon / bəˈloōn/ • n. 1. a brightly colored rubber sac inflated with air and then sealed at the neck, used as a children's toy or a decoration: the room was festooned with balloons and streamers | fig. his derision pricked the fragile balloon of her vanity. ∎  a round or pear-shaped outline in which the words or thoughts of characters in a comic strip or cartoon are written: a balloon reading “Ka-Pow!”2. a large bag filled with hot air or gas to make it rise in the air, typically carrying a basket for passengers: a hot-air balloon.• v. [intr.] 1. swell out in a spherical shape; billow: the trousers ballooned out below his waist ∎  (of an amount of money) increase rapidly: the company's debt has ballooned in the last five years | [as adj.] (ballooning) ballooning government spending. ∎  swell dramatically in size or number: the public payroll ballooned from about 27,000 people to about 66,000 people ∎  (of a person) increase rapidly and dramatically in weight: I had ballooned on the school's starchy diet.2. travel by hot-air balloon: he is famous for ballooning across oceans.• adj. resembling a balloon; puffed: a flouncy balloon curtain.ORIGIN: late 16th cent. (originally denoting a game played with a large inflated leather ball): from French ballon or Italian ballone ‘large ball.’