material science teachers’ aide
Unit: Properties of Matter
Subject: Physical Properties
Grade Level: 7– 9
Key topics: Metal, Alloy, Ceramic
Light bulb:
Lab Act ivit y
Developed by: Andy Nydam, Teacher ( andrewnydam@hot mail.com) and
Debbie Goodwin, Teacher ( nywin@hot mail.com)
T able of Cont e nt s
Overview...........................................................................................
Science St andards Addressed ..........................................................
Goals/ Object ives .............................................................................
Mat erials and Equipment ..................................................................
Key Vocabulary Words .....................................................................
Saf et y ...............................................................................................
Procedure ( t ot al est imat ed t ime- 1 hr) ............................................
Assessment Examples ......................................................................
Locat ing Mat erials ............................................................................
Background Inf ormat ion ...................................................................
Ref erences........................................................................................
Acknowledgment ..............................................................................
Ove rvie w
St udent s observe what mat erials are inside an incandescent light bulb.
St udent s learn about dif f erent classes of mat erials including met als, and
ceramics. The light bulb globes are broken, and t he f ilament is burned in
air.
Scie nce St andards Addre sse d
U.1 Syst ems, order, and organizat ion
U.5 Form and f unct ion
B.1 Propert ies and changes of propert ies in mat t er
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material science teachers’ aide
Unit: Properties of Matter
Subject: Physical Properties
Grade Level: 7– 9
Key topics: Metal, Alloy, Ceramic
Goals/ Obje ct ive s
•
•
•
•
Learn and apply laborat ory saf et y procedures as covered in class.
Work cooperat ively t o decipher and f ollow direct ions.
Be able t o name t he part s of an incandescent light bulb.
Underst and why t here is a powdery subst ance inside t he bulb.
Mat e rials and Equipme nt
•
•
•
•
•
•
6 0 wat t light bulbs
4 0 wat t light bulbs
1 0 0 wat t light bulbs
t riangular f iles
goggles and aprons
power source wit h light bulb base
Ke y V ocabulary Words
Me t al - A mat erial t hat is usually hard, shiny, solid, and malleable. Met als
are good conduct ors of heat and elect ricit y.
Alloy - A solid solut ion of met als.
Ce ramic - Compounds made f rom met als bonded wit h non-met als.
Ceramics are hard, and brit t le. They are t hermal and elect rical
insulat ors. Glass is a special t ype of ceramic
Duct ile - Workabilit y, mat erials t hat can easily be changed in shape.
Duct ile mat erials can be rolled int o sheet s, drawn int o wires, et c.
Brit t le - Mat erials t hat are hard and cannot readily be changed in shape
wit hout breaking
Saf e t y
Safety goggles and lab aprons are required for this activity.
Glass shards are sharp. Light bulbs can get very hot.
Proce dure ( t ot al e st imat e d t ime - 1 hr)
Focusing Event
• St udent s leave t heir regular inst ruct ional classroom t o go t o t he
science lab.
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material science teachers’ aide
Unit: Properties of Matter
Subject: Physical Properties
Grade Level: 7– 9
Key topics: Metal, Alloy, Ceramic
Teaching Met hods and St udent Act ivit ies
• First , st udent s put on goggles and aprons f or saf et y purposes.
• An explanat ion is t hen given about t he light bulb, it s various part s,
and why t his lab is being done.
• The t eacher t hen demonst rat es t o t he st udent s how t o properly
score t he glass wit h t he f ile in order t o pull t he base f rom t he
envelope wit hout breaking t he bulb.
• A reminder is given t o be very caref ul as t hey are dealing wit h
glass.
• St udent s are given permission t o work wit h t heir laborat ory part ner
t o t ake apart t he bulb t hey have been given.
• As st udent s work, t he t eacher mills around t he room checking on
t heir progress, asking quest ions, and giving t hem t ips on how t o
get t he bulb apart .
• St udent s complet e laborat ory sheet s given in t heir regular
classroom prior t o leaving f or t he science lab.
• When it looks like all groups have successf ully t aken apart t heir
bulbs, t he t eacher t hen asks t he st udent s what t hey have
discovered inside t he envelope.
• The t eacher t hen t akes a disassembled bulb and caref ully places it
int o an elect rical socket wit h t he device unplugged. The t eacher
asks t he st udent s what t hey t hink will happen when t he bulb is
plugged in. Being caref ul not t o look at t he f ilament , t he power
plug is insert ed in t o t he out let .
• Discussion t hen ensue about what happened, why, and did it mat ch
up wit h what t hey t hought would t ake place.
• St udent s are given t he opport unit y t o ask quest ions, make
comment s, and t o writ e more inf ormat ion on t heir lab sheet s.
Closure
• St udent s are asked t o clean up t heir lab st at ions.
• Everyone ret urns t o t he general classroom t o complet e t he
discussion on t he dif f erent t ypes of light bulbs and t heir uses.
Tear-Down ( 5 Minut es)
Gat her all used lab equipment . Dispose of broken light bulb in t he t rash.
Be caref ul of sharp edges.
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material science teachers’ aide
Unit: Properties of Matter
Subject: Physical Properties
Grade Level: 7– 9
Key topics: Metal, Alloy, Ceramic
Asse ssme nt Example s
1 . How does a light bulb work?
2 . What ’s t he dif f erence bet ween t hese light bulbs? Which one gives
more light ? Which one has more power? How do t hey give dif f erent
amount s of light and power?
3 . Which one has more resist ance? How do t hey have dif f erent
amount s of resist ance?
4 . Are all t he f ilament s made out of same mat erial? Are all t he
f ilament s t he same lengt h? Are all t he f ilament s t he same
t hickness?
5 . Which has more resist ance: long or short wire? t hick or t hin wire?
Observat ions and Int erpret at ion Act ivit ies and Quest ions ( in it alics) :
Dismant le light bulbs and make observat ions of glass envelope and
t ungst en f ilament .
Look at f ilament s under st ereoscope.
Burn t he f ilament s.
Why do we need t he glass envelope?
What causes a light bulb t o f ail?
When does it f ail?
Does it really “ burn-out ” ?
Remove t he f ilament f rom a “ burned-out ” light bulb and check it s
charact erist ics.
The f ilament breaks but it isn’t really oxidized ( burned) .
So why does it break?
What is inside t he glass envelope? A vacuum or a gas?
Heat t he envelope wt ih a propane t orch.
Dimple it in f irst if possible. Make several bumps. Let a bump “ pop” and
blow out t he t orch f lame – it is an inert gas. Argon and nit rogen mixt ure.
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material science teachers’ aide
Unit: Properties of Matter
Subject: Physical Properties
Grade Level: 7– 9
Key topics: Metal, Alloy, Ceramic
Why put a gas inside t he envelope?
Why not leave it a vacuum?
Show an old bulb wit h a dark ring or spot . Talk about changing a light
bulb wit h a new one of t he same wat t age and not icing t hat it looks
bright er.
A hot t ungst en f ilament undergoes sublimat ion.
Sublimat ion – solid st at e t o gas st at e w/ o becoming a liquid.
Locat ing Mat e rials
Light bulbs and propane t orch can be f ound at t he hardware st ore.
Background Inf ormat ion
How light bulbs are made:
The glass enclosures are made f rom a ribbon of hot glass t hat ' s f irst
t hickened and t hen blown int o molds t o f orm t he bulb shapes. These
enclosures are t hen cooled, cut f rom t he ribbon, and t heir insides are
coat ed wit h t he dif f using mat erial t hat gives t he f inished bulb it s sof t
whit e appearance.
The f ilament is f ormed by drawing t ungst en met al int o a very f ine wire.
This wire, t ypically only 4 2 microns ( 0 .0 0 1 7 inches) in diamet er is f irst
wound int o a coil and t hen t his coil is it self wound int o a coil. The
mandrels used in t hese t wo coiling processes are t rapped in t he coils and
must be dissolved away wit h acids af t er t he f ilament has been annealed.
The f inished f ilament is clamped or welded t o t he power leads, which have
already been embedded in a glass support ing st ruct ure. This glass support
is insert ed int o a bulb and t he t wo glass part s are f used t oget her. A t ube
in t he glass support allows t he manuf act urer t o pump t he air out of t he
bulb and t hen reint roduce various inert gases. When virt ually all of t he
oxygen has been eliminat ed f rom t he bulb, t he t ube is cut of f and t he
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www.cityofmaterials.com
material science teachers’ aide
Unit: Properties of Matter
Subject: Physical Properties
Grade Level: 7– 9
Key topics: Metal, Alloy, Ceramic
opening is sealed. Once t he base of t he bulb has been at t ached, t he bulb
is ready f or use.
Re f e re nce s
ht t p:/ / bulbcollect or.com/ art icle0 1 0 .ht ml
BIG light bulb
ht t p:/ / rabi.phys.virginia.edu/ HTW/ incandescent _ light _ bulbs.ht ml
how t hings work
ht t p:/ / invent ors.about .com/ library/ invent ors/ bllight 2 .ht m
hist ory
ht t p:/ / science.howst uf f works.com/ light -bulb.ht m
how st uf f works
ht t p:/ / invsee.asu.edu/ nmodules/ light bulbmod/ burnout .ht ml
why light bulbs f ail
Acknowle dgme nt
This module was developed by t he ASM Foundat ion K-1 2 commit t ee' s
Middle School Task Force wit h input f rom t eachers and st af f and edit ing
assist ance f rom Pet er Kazarinof f , all of whose cont ribut ions are
acknowledged wit h t hanks.
Copyright ASM International 2010; Permission is granted for
free use by instructors for educational purposes.
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