A balloon is an inflatable flexible bag filled with a type of gas, such as helium, hydrogen, nitrous oxide or air. Modern balloons can be made from materials such as rubber, latex, polychloroprene, or a nylon fabric, while some early balloons were sometimes made of dried animal bladders. Some balloons are purely decorative, while others are used for specific purposes such as meteorology, medical treatment, military defense, or transportation. A balloon's properties, including its low density and relatively low cost, have led to a wide range of applications.

History

In 1643 Evangelista Torricelli, an Italian physicist, showed air was something more than nothing.

The balloon was invented by the Luso Brazilian priest (at 45 years of age) Bartolomeu de Gusmão (brother of the Luso Brazilian statesman Alexandre de Gusmão), and the first public exhibition was to the Portuguese Court on August 8, 1709, in the hall of the Casa da Índia in Lisbon.

Applications

Decoration or entertainment

Party balloons are mostly made of natural latex tapped from rubber trees, and can be filled with air, helium, water, or any other suitable liquid or gas. The rubber's elasticity makes the volume adjustable.

Filling the balloon with air can be done with the mouth, a manual or electric inflator (such as a hand pump), or with a source of compressed gas.

When rubber balloons are filled with helium so that they float, they typically retain their buoyancy for only a day or so. The enclosed helium atoms escape through small pores in the latex which are larger than the helium atoms. Balloons filled with air usually hold their size and shape much longer.

Even a perfect rubber balloon eventually loses gas to the outside. The process by which a substance or solute migrates from a region of high concentration, through a barrier or membrane, to a region of lower concentration is called diffusion. The inside of balloons can be treated with a special gel (for instance, the polymer solution sold under the "Hi Float" brand) which coats the inside of the balloon to reduce the helium leakage, thus increasing float time to a week or longer.

Beginning in the late 1970s, some more expensive (and longer-lasting) foil balloons made of thin, unstretchable, less permeable metalized plastic films started being produced. These balloons have attractive shiny reflective surfaces and are often printed with color pictures and patterns for gifts and parties. The most important attribute of metalized nylon for balloons is its light weight, increasing buoyancy and its ability to keep the helium gas from escaping for several weeks. Foil balloons have been criticized for interfering with power lines.

Professional balloon party decorators use electronic equipment to enable the exact amount of helium to fill the balloon. For non-floating balloons air inflators are used. Professional quality balloons are used, which differ from most retail packet balloons by being larger in size and made from 100% biodegradable latex.

Balloon modeling and balloons in art

Balloon artists are entertainers who twist and tie inflated tubular balloons into sculptures (see balloon modelling). The balloons used for balloon sculpture are made of extra-stretchy rubber so that they can be twisted and tied without bursting. Since the pressure required to inflate a balloon is inversely proportional to the diameter of the balloon^{[citation needed]}, these tiny tubular balloons are extremely hard to inflate initially. A pump is usually used to inflate these balloons.

Decorators may use hundreds of helium balloons to create balloon sculptures. Usually the round shape of the balloon restricts these to simple arches or walls, but on occasion more ambitious "sculptures" have been attempted. It is also common to use balloons as tables decorations for celebratory events. Balloons can sometimes be modeled to form different shapes of animals. Table decorations normally appear with 3 or 5 balloons on each bouquet. Ribbon is curled and added with a weight to keep the balloons from floating away.

Menno Baars is the first contemporary artist who turned a balloon into art. Within 5 days the Dutch artist painted a large primitive female nude on the huge balloon screen (800m2) in his typical violent colors and broad brush stroke. The balloon work of art was named " The independent Woman".

Balloon drops

A common decorative use for balloons is in balloon drops. In a balloon drop, a plastic bag or net filled with air-inflated balloons is suspended from a fixed height. Once released, the balloons fall onto their target area below. Balloon drops are commonly performed at New Year's Eve celebrations and at political rallies and conventions, but may also be performed at other celebrations, including graduations and weddings.

Balloon publicity

Balloons are often used for publicity at major events. Screen-printing processes can be used to print designs and company logos onto the balloons. In January 2008, the Jewish Community Relations Council of New York organized a display of 4,200 red balloons outside the United Nations building.