The Chemistry of Christmas Lights

• Wiring
  • Copper
• Plastic covering the wire
  • Polyvinyl chloride (PVC)C₂H₃Cl
• Filament
  • Tungsten
• Case around filament filled to glow
  • Argon
• The casing
  • Glass SiO₂

Main Chemicals, Compounds, Components

Glass(SiO₂), also known as silica, is a main component in christmas lights. It is melted down and formed into a bulb shape. It is then fit to be put around the filament of the light. It is made of sand, soda ash, and limestone. Glass was first used in christmas lights in 1880. It is used in christmas lights because it is resistant to high temperatures and can hold the Argon in around the filament.

Polyvinyl chloride(C₂H₃Cl), also known as PVC, is another important factor in christmas lights. It is polymerized and formed to cover the copper wiring. It is made of ethylene, chlorine, hydrogen, and carbon. PVC was first used for christmas lights in 1880 as well. It helps to run the electricity through the copper wiring without letting it touch or burn anything around it.

Chemistry's Role

How are glass and polyvinyl chloride made you might ask? This is how…

• Glass is made of sand mixed with waste glass, soda ash, and limestone. Soda ash is used to reduce the sands melting point, making the process more energy efficient. A drawback of this is that it produces a dissolvable glass. Limestone is added to prevent this from happening. Melting the mixture at high temps of 1700°C (3090°F) makes it able to be poured into molds of the shape that is wanted.
• PVC is made of vinyl chloride monomers which are a gas at ambient state but stored as a liquid under pressure. They are put together by polymerization (a process of reacting monomer molecules together in a chemical reaction to form three-dimensional networks). Ethylene and chlorine are raw materials put together to make ethylene dichloride. This is then transformed to vinyl chloride. The chlorine makes it compatible with other materials and flame retardant. PVC also contains hydrogen and carbon as elements involved in the process of making the final product.

Background Research

Christmas lights are not as complex as you may think they are. An electric current runs through the copper wire, that is covered with the polyvinyl chloride, to reach the filament. A contact wire brings the electric current to the filament, made of tungsten. The filament then gets hot and causes the inert gas, such as Argon, around the filament to glow. The glass casing around all of this can be different colors to make the season bright. With a closed circuit the electric current runs through the filament and back out of the bulb. In an open circuit the filament is burnt and the current cannot continue through it. Also, in the series of lights the electric current travels through each light and onto the next. That’s why if one light goes out, so do all of the ones after. In a parallel this does not happen because each light has it’s own circuit to the power source and the others can continue to get power, even though the other burned out.

Resources

http://people.howstuffworks.com/culture-traditions/holidays-christmas/christmas-lights.htm

• Mini lights(2.5-volt incandescent bulb)- typical strand at the store
  • Used in a series, 2.5x48=120volts that its plugged into
    • explains why one bulb gone can stop the strand from working

https://en.wikipedia.org/wiki/Christmas_lights

• History on them

http://www.loc.gov/rr/scitech/mysteries/christmaslights.html

• Why they work
• What is involved

http://energy.gov/articles/how-do-holiday-lights-work

• Open circuit and closed circuit
• Series and parallel
• LED’s
• http://www.popularmechanics.com/home/how-to/a3231/how-to-fix-a-string-of-christmas-lights-14774047/
• How to fix lights
• Voltage detector

https://www.decodedscience.org/how-christmas-lights-work/5755

• Incandescent bulbs
• why lights burn out so quickly

http://www.pvc.org/en/p/how-is-pvc-made

• PVC is made

http://www.explainthatstuff.com/glass.html

• Glass is made

http://gizmodo.com/5425395/christmas-lights-the-brief-and-strangely-interesting-history-of

• Didn’t start as decoration
• Used to be so expensive, suggested to rent instead

http://www.madehow.com/Volume-5/Holiday-Lights.html

• How the lights are manufactured
• 22-gauge copper wire covered with green plastic
• Injection molded plastic
• Plastic resin
• Glass
• UV additives
• Each bulb uses 600 milliamps of energy

http://archive.onearth.org/articles/2013/12/christmas-lights-are-coated-with-toxic-chemicals-lead

• Lead on PVC of all lights
  • Can be dangerous/ maybe illegal?

https://www.decodedscience.org/how-christmas-lights-work/5755

• Contact wires connect filament to electric circuit
• A case protects the filament(tungsten) made of material resistant to high temp(glass) as the bulb can get very hot(more than 200 C)
  • Case filled with inert gas, such as Argon
  • High temps cause glowing and light

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