Rocket (firework)

A rocket is a pyrotechnic device made out of a paper tube that propels itself into the air in order to fly. Types of rockets include the skyrockets, which have a stick to provide stability during airborne flight; missiles, which rotate rather than having a stick for stability, or are shot out of a tube; and bottle rockets, smaller fireworks – 1½ in (3.8 cm) long, though the attached stick extends the total length to approximately 12 in (30 cm) – that usually contain whistle effects.

History

Developed in the second-century BCE, by the ancient Chinese, fireworks are the oldest form of rockets and the most simplistic model of a rocket. Originally fireworks had religious purposes in ceremonies but were later adapted for military use during the Middle Ages in the form of "flaming arrows." During the tenth and thirteenth centuries the Mongols and the Arabs brought the major component of these early rockets to the West: gunpowder. Although the cannon and gun became the major developments from the eastern introduction of gunpowder, a tickling of rockets also resulted. These rockets were essentially enlarged fireworks which propelled, further than the long bow or cannon, packages of explosive gunpowder. During the late eighteenth century imperialistic wars, Colonel Congreve, developed his famed rockets, which travel range distances of four miles. The "rockets' red glare" (American Anthem) records the usage of rocket warfare, in its early form of military strategy, during the inspirational battle of Fort McHenry.

Popularity

Fireworks have remained popular in today's age due to the spectacle of colors and sounds they are so renown for. The component of a rocket that produces these stars, reports ("bangs"), and colors is typically located just below the nosecone (figure 1.7) section of a rocket. After the rocket engine has consumed all of its fuel an internal fuse is lit that delays the release of the stars, or other effect. This delay allows for coasting time where the rocket continues its ascent. As gravity will eventually pull the firework back to earth, it slows and eventually reaches an apex (highest point: where velocity of the rocket is zero) and begins its descent. The delay usually lasts just before this apex, at an optimum velocity, where a small explosion shoots the firework's stars in desired directions and thus producing a brilliant effect. The colors, reports, flashes, and, stars are analogous to flavor one adds with spices (chemicals with special pyrotechnic properties) to a soup of otherwise bland gunpowder.

Advantages and disadvantages

Gunpowder's relatively low specific impulse (amount of thrust per unit propellant) limits its capacity of thrust production on larger scales. Fireworks are the simplest of solid rockets and the weakest. Evolution from fireworks brought about more complex solid fueled rockets, which use more exotic and powerful fuels. The low-explosive properties of gunpowder, relative to the high-explosive properties of more advanced solid fuels testify to the "survival of the fittest," as the use of firework-type engines (for purposes other than entertainment or education) has virtually ceased since the late nineteenth century. Yet with all these drawbacks fireworks will continue to maintain their use as a traditional pastime with an on-going history of nearly 5,000 years.

References

* http://inventors.about.com/library/inventors/blrocketfirework.htm
* http://adc.gsfc.nasa.gov/adc/education/space_ex/firework.html