Tyra Harper Chemistry Flaming fireworks
The Chemistry Of Firework Color • There are two main mechanisms of color production in fireworks, incandescence and luminescence. • Incandescence • Incandescence is light produced from heat. Heat causes a substance to become hot and glow, initially emitting infrared, then red, orange, yellow, and white light as it becomes increasingly hotter. • Luminescence • Luminescence is light produced using energy sources other than heat. Sometimes luminescence is called 'cold light', because it can occur at room temperature and cooler temperatures. To produce luminescence, energy is absorbed by an electron of an atom or molecule, causing it to become excited, but unstable. When the electron returns to a lower energy state the energy is released in the form of a photon (light). The energy of the photon determines its wavelength or color.
Invention of Fireworks • Many people associate fireworks with Independence Day, but their original use was in New Year's celebrations. Do you know how fireworks were invented? Legend tells of a Chinese cook who accidentally spilled saltpeter into a cooking fire, producing an interesting flame. Saltpeter, an ingredient in gunpowder, was used as a flavoring salt sometimes. • The other gunpowder ingredients, charcoal and sulfur, also were common in early fires. Though the mixture burned with a pretty flame in a fire, it exploded if it was enclosed in a bamboo tube.
Fast Facts • Fireworks are used mostly for celebrations or major events. • Fireworks were originally invented in ancient China in the 12th century to scare away evil spirits, as a natural extension of the Chinese invention of gunpowder. Such important events and festivities as Chinese New Year and the Mid-Autumn Moon Festival were and still are times when fireworks are guaranteed sights. • China is the largest manufacturer and exporter of fireworks in the world.
The fireworks Periodic Table • Fireworks rely on the chemical characteristics of the elements that are used to make them. This special periodic table highlights the elements that have significance to fireworks.
Firecrackers vs. Rockets • In addition to exploding gunpowder for firecrackers, the Chinese used gunpowder combustion for propulsion. Hand carved wooden rockets, shaped like dragons, shot rocket-powered arrows at the Mongol invaders in 1279. • Explorers took knowledge of gunpowder, fireworks, and rockets back with them when they returned home. Arabians in the 7th century referred to rockets as Chinese arrows. Marco Polo is credited with bringing gunpowder to Europe in the 13th century. The crusaders also brought the information with them. F I R E C R A C K E r R O C K E T S
The Chemistry in Fireworks • Fireworks generate three very noticeable forms of energy: a tremendous release of sound, bright light, and heat. The tremendous booms heard at ground level are the result of the rapid release of energy into the air, causing the air to expand faster than the speed of sound. This produces a shock wave, a sonic boom. • The colors are produced by heating metal salts, such as calcium chloride or sodium nitrate, that emit characteristic colors. The atoms of each element absorb energy and release it as light of specific colors. The energy absorbed by an atom rearranges its electrons from their lowest-energy state, called the ground state, up to a higher-energy state, called an excited state. The excess energy of the excited state is emitted as light, as the electrons descend to lower-energy states, and ultimately, the ground state. • The amount of energy emitted is characteristic of the element, and the amount of energy determines the color of the light emitted. For example, when sodium nitrate is heated, the electrons of the sodium atoms absorb heat energy and become excited. This high-energy excited state does not last for long, and the excited electrons of the sodium atom quickly release their energy, about 200 kJ/mol, which is the energy of yellow light.
Ancient Rockets Urban Rockets
Resources and Sites • www.google.com • www.answers.com • www.wikipedia.com