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FIREWORKS, SCIENCE THAT LIGHTS UP THE SKY

Introduction

The idea of celebrating special events in this world has been around since the beginning of history itself. Mankind has been marking occasions such as childbirths, marriages, planting and harvesting seasons, birthdays, and especially historic events of ones country or state. These celebrations have been made up of many different cultural traditions from singing and dancing to sacrifices but the use of fireworks has become the single most common feature of the party. We as a country, during the end of the revolutionary war, used fireworks to inspire the men and the country with hope and patriotism that enabled us to win our freedom. One year after signing the declaration of independence we celebrated our first Fourth of July in 1777 with large displays of fireworks representing the freedom of this young country. This celebration continues every year here in the United States and others like it all over the world using this chemical reaction as a canvas for entertainment.

History of Fireworks

The history of fireworks goes back to the early days of the Han Dynasty in China (200 B.C.), long before gunpowder was invented. The first “firecracker” was said to have been small cut pieces of bamboo tube that when put into a fire would explode with a loud bam! This was caused by trapped air and sap that expanded when heated and escaped with force through the sides of the tube causing the noise. These first firecrackers were used in special occasions such as weddings and royal events to chase away the bad spirits. The pao-chuk or bursting bamboo was used in China for over 1000 years. During the Sui and Tang Dynasties in China (600-900 A.D.) while trying to develop an elixir to prolong life a alchemist mixed sulphur, saltpeter, honey, and arsenic disulfide together. While cooking the mixture up it ignited and burst into a hot, bright red flame that was very powerful and unstable. The Chinese alchemist started experimenting with this reaction and found that the amount of saltpeter or potassium nitrate was the key to the size or power of the reaction. The saltpeter was found to release large amounts of oxygen when burned increasing the speed of the chemical reaction thus increasing the pressure of the gases given off. This increase in the speed and pressure of the burning gases is what determines the size and magnitude of the burn or explosion. The development of this chemical reaction was the invention of the fireworks we have today. The recipe used in today’s fireworks is the same as it was in the 11th century, 75% saltpeter, 10% sulphur, and 5% charcoal.   The creation of this compound allowed us not only to celebrate events beautifully but to kill each other in large numbers more efficiently. By the 12th century cannons were being used by the Chinese and this technology spread all over Europe. In the period between 1400 and 1600’s gunpowder was now more powerful, stable, and easily used in weapons. In our presentation we decided to concentrate on the beautiful use of this chemical reaction not the ugly one.

Types of Fireworks

Sparklers: Sparklers are long, metal wires that when lit, crackle and give off short rays of sparks. The metal wire is extremely hot during and after use. Rockets: There are two types of rockets: bottle rockets and sky rockets. Sky Rockets: Sky rockets are greater than one foot in length and contain more impressive effects such as stars, crackle, strobes and even parachutes. Repeaters and Cakes: Repeaters and cakes are one of the most popular types of fireworks. They are basically a fireworks show all in one. Repeaters usually consist of many tubes attached together ranging anywhere from half a dozen to nearly 100. A repeater always has a fuse on the lower side. Each tube of a repeater is a tiny aerial shell type device. A single fuse burns between the tubes. When it reaches one, the lifting powder inside ignites and shoots the effects high into the air.

Chemical Reactions

Sodium is used for the colors gold and or yellow, although it so intense it ends up taking over less intense colors. Calcium is used to increase the intensity of the colors in the fireworks while calcium salts are used to produce the orange color. Copper produces a blue green color in fireworks Barium salts are used to create green in fireworks. Aluminum is used to produce silver and white flames and sparks. Zinc is used to create smoke effects Carbon is used to provide fuel for the fireworks. Oxygen is used for the fireworks to burn. Phosphorus burns spontaneously and helps with the glow-in-the dark effects. Sulfur is another component in the fireworks fuel. Chlorine is a component of the oxidizers in fireworks. Antimony is used to create firework glitter effects.

Fireworks generate 3 forms of energy

  • Release of sound
  • Bright lights
  • Heat

    Sound

    Sound is caused by the result of the rapid release of energy into the air, causing the air to expand faster than the speed of sound This is when you hear a loud sound during a fireworks display

    Heat

    By heating metal salts a color is produced. Elements such as calcium chloride or sodium nitrate emits color. The energy absorbed by an atom rearranges it’s electrons from the lowest energy level to a higher one (from ground state to excited state). The excess energy of the excited state is the light. The amount of energy that is emitted is a characteristic of the element, and the amount of energy determines the color of the light Example: As sodium nitrate is heated the electrons of the sodium atoms absorb heat and become excited. As the atom releases energy it gives off the yellow light.

    Bright Lights

    The amount of energy released depends on the wavelength of light which is different from element to element Higher energies corresponds to shorter wavelengths. Located in the violet/blue region. Lower energies corresponds to longer wavelengths at the orange/red region. For further information visit the following sites (just copy and paste into your web browser) www.20ishparents.com/holiday/july4th/fireworks.shtml

  • Our Group:

  • Honcho- Dan
  • Web Coordinator- Karen
  • Researcher- Liz
  • Presentation- Michelle

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