Light Bulb

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Light Bulb

• By Chelsea Hogan
• 4/5/04

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Elements contained in light bulbs

• Argon
• Krypton
• Neon
• Tungsten

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Argon

• Argon is tasteless, colorless, odorless
• When you remove all the oxygen and nitrogen from
  the air the heaviest gas that is left is argon
• It is also the first discovered noble gas
• Argon has an atomic number of 18 meaning it has 8
  valence electrons making it stable and chemically
  motionless
• Argon is used in place of oxygen enriched air
  that corrodes tungsten filament and blackening of
  the bulb

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Krypton

• Like Argon Krypton is also tasteless, colorless,
  and odorless
• Krypton is a noble or an inert gas one that will
  not usually combine with other elements
• Krypton is used alone or with the elements Argon
  and the element neon in incandescent light bulbs
• Krypton is used because it has a high melting
  point and the elements with high melting points
  are used because the most efficient light comes
  from the highest filament temperature

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Neon

• Just like the other elements in light bulbs Neon
  is tasteless, colorless, and odorless
• Its a noble gas and it is stable with 8 valence
  electrons
• Neon is the fourth most abundant element in the
  universe
• Neon is used in light bulbs because of its unique
  glow

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Tungsten

• Tungsten is a really strong refractory metal used
  in steels to increase hardness and strength and
  in lamp filaments
• It is a steel gray to tin-white metal
• Tungsten has the highest melting point of all
  metals
• Tungsten has an excellent corrosion resistance
• Pure Tungsten is ductile
• Tungsten was first employed as a lamp filament
  material and thereafter used in many electronic
  applications

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How are light bulbs made?

• A ribbon of hot glass is made into glass
  enclosures
• The glass is first thickened and the formed into
  the bulb shaped molds
• The enclosures are coated with a diffusing
  material that gives the bulb its white look
• Then they use tungsten metal to form the filament
  by drawing it into a very thin wire
• It is first wound into a coil and that coil is
  wound into another coil

• A finished filament must be welded to the power
  leads these are embedded in a glass supporting
  structure
• The two glasses are fused together after the
  glass support is inserted into a bulb
• A tube in the glass support allows air to be
  pumped out and the inert glasses to be inserted
• After all of the oxygen is out of the bulb the
  tube is cut off and the opening is sealed

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Where Tungsten is mined

• The most common tungsten deposits are in
  California, Colorado, South Korea, Bolivia,
  Russia, and Portugal
• 75 of the worlds tungsten resources is are found
  in China

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How light bulbs effect our environment

• There is a lead bead on the end of every bulb
  making incandescent light bulbs a hazardous waste
• Ken Shollenberger invented a way to cut of the
  hazardous tip of the light bulb to lessen the
  amount of hazardous waste when they are disposed
• They remove the tips and then they are packaged
  in plastic bags and await disposal as hazardous
  wastes

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History of the light bulb

• In 1809 Davy an English chemist was the first to
  invent an electric light by connecting wires
• In 1820 Warren Da la Rue enclosed a coil in a
  tube and an electrical current passed through it
  but the metal was to costly
• In 1835 James Bowman Lindsay invented a lighting
  system
• In 1854 the first true light bulb was invented by
  Henricg Global

• During 1880 Edison improved his light bulb until
  it could last for more than 1200 hours using
  bamboo-derived filament
• In 1903 Willis Whitnew invented a filament that
  wouldnt make the inside of the light bulb turn
  dark
• The General Electric Company was the first to
  start a method of making incandescent light bulbs
• In 1991 Phillips invented a light bulb that lasts
  60,000hours it uses magnetic induction

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Bibliography

• http//library.thinkquest.org/C0113863/Argon.html
• http//library.thinkquest.org/C0113863/Krypton.sht
  ml
• http//library.thinkquest.org/Co113863/Neon.shtml
• http//library.thinkquest.org/C0113863.Tungsten.sh
  tml
• http//science.howstuffworks.com/light-bulb3.htm
• http//www.speclab.com/elements/tungsten.htm

• http//www.er.doe.gov/epic/DOCS/391.STM
• http//inventors.about.com/library/inventors/bllig
  ht2.htm

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Chelsea

School
Clark

Middle
7th Grade