r11700062 - files.eric.ed.govscience fun with electricity. 640 bc. ma les of miletus discovers...
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AUTHORTITLE
INSTITUTION
SPONS AGENCY
REPORT NOPUB DATECONTRACTNOTEAVAILABLE FROM
PUB TYPE
EDRS PRICEDESCRIPTORS
DOCUMENT RESUME
SE 053 921
Horton, Robert L.Science Fun with Electricity...Discoveries andInnovations.National Center for Science Teaching and Learning,Columbus, OH.; Ohio State Univ., Columbus.Cooperative Extension Service.Office of Educational Research and Improvement (ED),Washington, DC.FS-4-H-531Sep 93R1170006249p.National Center for Science Teaching and Learning,1929 Kenny Road, Columbus, OH 43210.Guides Classroom Use Instructional Materials (ForLearner) (051)
MF01/PCO2 Plus Postage.*Electric Batteries; *Electricity; Elementary SchoolStudents; Intermediate Grades; Physics; *ScienceActivities; Science Education; Science History;Scientific Concepts; Secondary Education; SecondarySchool Students
IDENTIFIERS 4 H Programs
ABSTRACTThis project manual is written for 4-H member
children who are in the fifth grade or older. This project isdesigned to familiarize members with the scientific historyconcerning the discovery and application of electric energy throughthe 1800's. Readers can conduct experiments similar to the onesperformed by the scientists and inventors of that day. Topics includestatic electricity, current electricity, electromagnetism,electromagnets, electric generation, electric motors, and electriclight. (PR)
***********************************************************************
Reproductions supplied by EDRS are the best that can be madefrom the original document.
***********************************************************************
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IDE
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OU
ND
Thi
s be
ginn
ing
leve
l pro
ject
is w
ritte
n fo
r m
embe
rs w
ho a
re in
the
fifth
gra
de o
r ol
der.
You
nger
mem
bers
may
take
this
pro
ject
und
er th
e su
perv
isio
n of
an
adul
t. D
ue to
the
tech
nica
l nat
ure
of th
e pr
ojec
t, m
embe
rs m
ay fo
cus
on a
few
of t
he A
ctiv
ities
per
yea
r.T
his
will
allo
w th
e in
divi
dual
to e
xplo
re th
orou
ghly
eac
h ex
perim
ent a
nd D
iggi
ng D
eepe
rA
ctiv
ity. I
t will
als
o he
lp r
educ
e th
e co
sts
asso
ciat
ed w
ith c
ompl
etin
g al
l the
exp
erim
ents
and
activ
ities
in o
ne y
ear.
Thi
s pr
ojec
t is
desi
gned
to fa
mili
ariz
e m
embe
rs w
ith th
e sc
ient
ific
hist
ory
conc
erni
ngth
e di
scov
ery
and
appl
icat
ion
of e
lect
ric e
nerg
y th
roug
h th
e 18
00's
. Mem
bers
will
con
-du
ct e
xper
imen
ts s
imila
r to
the
ones
per
form
ed b
y th
e sc
ient
ists
and
inve
ntor
s of
that
day
.
As
mem
bers
mov
e th
roug
h th
e m
anua
l the
y w
ill n
ote
that
the
expe
rimen
ts h
ave
been
orga
nize
d ch
rono
logi
cally
to th
eir
plac
e in
his
tory
. Thi
s al
low
s th
e m
embe
rs, l
ike
earli
ersc
ient
ists
, to
build
upo
n pr
evio
us d
isco
verie
s.
Mem
bers
sho
uld
also
not
e th
e tim
elin
e w
hich
run
s th
roug
h th
e bo
ok. I
t pro
vide
s a
grap
hic
repr
esen
tatio
n of
the
hist
oric
al d
evel
opm
ent o
f ele
ctric
ity. N
ote
that
onc
e th
eba
sics
of e
lect
ricity
had
bee
n le
arne
d, in
vent
ors
like
Edi
son
and
Mor
se q
uick
ly a
ppea
red
on th
e sc
ene
to a
pply
this
new
kno
wle
dge.
Thi
s is
evi
dent
by
the
abun
danc
eof
dat
es a
nd
even
ts to
war
d th
e en
d of
the
19th
cen
tury
as
com
pare
d to
the
begi
nnin
g. In
fact
thin
gsw
ere
happ
enin
g so
fast
that
onl
y a
frac
tion
of th
e im
port
ant e
vent
s ar
e lis
ted.
Che
ck y
our
coun
ty p
roje
ct g
uide
lines
for
addi
tiona
l req
uire
men
ts fo
r ta
king
this
proj
ect,
espe
cial
ly if
you
cho
ose
to p
artic
ipat
e in
cou
nty
proj
ect j
udgi
ng o
r pr
epar
e an
exhi
bit f
or th
e fa
ir. M
embe
rs w
ho c
ompl
ete
this
pro
ject
are
enc
oura
ged
to m
ove
to th
e
next
leve
l of 4
-H e
lect
ric e
nerg
y pr
ojec
ts.
.P
RO
JEC
T G
UID
ELI
NE
S
1.C
ompl
ete
the
Pla
nnin
g S
ectio
n of
this
gui
de (
step
s 1-
4).
2.E
xplo
re e
ach
of th
e P
roje
ct In
k.i e
st A
reas
.
3.C
ompl
ete
at le
ast o
ne o
f the
exp
erim
ents
for
each
Inte
rest
Are
a se
lect
ed. D
iggi
ng D
eepe
r A
ctiv
ities
are
optio
nal.
4. B
uild
a D
C m
otor
from
scr
atch
or
from
a k
it. S
ee p
age
20fo
r de
tails
.
5.T
ake
part
in a
t lea
st tw
o O
rgan
ized
Pro
ject
Act
iviti
es.
6.B
ecom
e in
volv
ed in
at l
east
two
Citi
zens
hip/
Lead
ersh
ipac
tiviti
es.
6
7
SC
IEN
CE
FU
N W
ITH
ELE
CT
RIC
ITY
PLA
NN
ING
YO
UR
PR
OJE
CT
Ste
ps 1
and
2P
RO
iEC
T I
NT
E R
E S
T A
RE
AS
AN
D A
CT
IVIT
IES
Exp
lore
eac
h of
the
Pro
ject
Inte
rest
Are
as li
sted
. Pla
nto
com
plet
e at
leas
t one
of t
he e
xper
imen
tsin
eac
h
Inte
rest
Are
a. D
iggi
ng D
eepe
r A
ctiv
ities
are
opt
iona
l.H
ave
your
par
ent o
r ad
viso
r in
itial
and
dat
e w
hat y
ouco
mpl
ete.
4 SC
IEN
CE
FU
N W
ITH
ELE
CT
RIC
ITY
Dat
e C
ompl
eted
Inte
rest
Are
as a
d A
ctiv
ities
1. S
TA
TIC
ELE
CT
RIC
ITY
, pag
e 8
Exp
erim
ent 1
Cha
rge
a B
allo
on
Exp
erim
ent 2
Sta
tic E
lect
ricity
Lig
ht
2. C
UR
RE
NT
ELE
CT
RIC
ITY
, pag
e 10
Exp
erim
ent 3
Ton
gue
Tes
t
Dig
ging
Dee
per
Get
ting
Ele
ctric
ity F
rom
a L
emon
Dig
ging
Dee
per
Pot
ato
Pol
arity
Indi
cato
r
3. E
LEC
TR
OM
AG
NE
TIS
M, p
age
12E
xper
imen
t 4M
agne
tic F
ield
Aro
und
a C
urre
ntC
arry
ing
Wire
Exp
erim
ent 5
Mak
ing
a G
alva
nsco
pe
4. E
LEC
TR
OM
AG
NE
T, p
age
15E
xper
imen
t 6M
ake
an E
lect
rom
agne
t
Dig
ging
Dee
per
Pol
arity
Che
ck
Dig
ging
Dee
per
Mag
netiz
e a
Scr
ewdr
iver
5. E
LEC
TR
IC G
EN
ER
AT
ON
, pag
e 17
Exp
erim
ent 7
Indu
ce C
urre
nt F
rom
a M
agne
t
Dig
ging
Dee
per
AC
/DC
Det
ectio
n
6. E
LEC
TR
IC M
OT
OR
, pag
e 19
Act
ivity
Mag
netic
For
ce
Exp
erim
ent 8
Bui
ld a
DC
Ele
ctric
Mot
or
7. E
LEC
TR
IC L
IGH
T, p
age
22E
xper
imen
t 9Li
ght a
Coi
led
Str
and
of W
ire
Ste
p 3
OR
GA
NIZ
ED
PR
OJE
CT
Arr
Ivrn
Es
Sel
ect t
wo
of th
e or
gani
zed
proj
ect a
ctiv
ities
list
edbe
low
, and
pla
n yo
ur in
volv
emen
t in
the
Rep
ort o
f Org
a-ni
zed
Act
iviti
es c
hart
. Bef
ore
star
ting
your
pro
ject
writ
eyo
ur c
hoic
es in
the
sect
ion
labe
led
Pla
n T
o D
o. O
nce
you
have
take
n pa
rt in
an
activ
ity, r
ecor
d w
hat y
ou d
id a
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Org
aniz
ed A
ctiv
ities
may
be
adde
d or
cha
nged
at
any
time. S
ampl
e O
rgan
ized
Act
iviti
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nty
Judg
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n T
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ate
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Dat
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5/28
Inte
rest
Are
as a
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ctiv
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Wia
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Aoe
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9 e
lect
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at
awm
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SC
IEN
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N W
ITH
ELE
CT
RIC
ITY
Ste
p 4
LEA
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HIP
/CIT
IZE
NS
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AC
TIV
ITIE
SC
heck
the
activ
ities
you
wis
h to
do
or p
lan
your
ow
nin
the
spac
e pr
ovid
ed. D
o at
leas
t tw
o. K
eep
trac
k of
you
r
prog
ress
by
mar
king
the
date
(m
onth
and
yea
r) w
hen
you
are
thro
ugh.
Lea
ders
hip/
Citi
zens
hip
activ
ities
may
be
adde
d or
cha
nged
at a
ny ti
me.
Whe
n I F
inis
hed
Lead
ersh
ip/C
itize
nshi
p A
ctiv
ities
Enc
oura
ge s
omeo
ne to
take
an
elec
tric
pro
ject
.
Hel
p so
meo
ne w
ith h
is o
r he
r el
ectr
ic p
roje
ct.
Org
aniz
e an
ele
ctric
saf
ety
clin
ic in
you
r co
mm
unity
.
Invi
te s
omeo
ne to
talk
to y
our
club
on
elec
tric
ity.
Pre
pare
and
exh
ibit
or p
oste
rab
out e
lect
ricity
.
Tea
ch s
omeo
ne s
omet
hing
you
lear
ned
abou
tel
ectr
icity
.
Enc
oura
ge a
frie
nd to
join
4-H
.
App
ly s
omet
hing
you
lear
ned
abou
t ele
ctric
ityto
bene
fit y
our
fam
ily.
Hel
p a
mem
ber
prep
are
his
or h
erel
ectr
ic p
roje
ct fo
r
Hel
p a
mem
ber
prep
are
an e
lect
ricex
hibi
t for
the
coun
ty fa
ir.
Pla
n yo
ur o
wn
activ
ities
her
e.
1 3
SC
IEN
CE
FU
N W
ITH
ELE
CT
RIC
ITY
PR
OJE
CT
RE
VIE
WO
nce
you
com
plet
e w
hat y
ou p
lann
ed, a
rran
ge fo
rlo
cal p
roje
ct r
evie
w. T
his
revi
ew c
an ta
ke p
art w
ith y
our
pare
nt, p
roje
ct a
dvis
or o
r in
tere
sted
adu
lt. It
may
also
be
part
of a
mor
e co
mpr
ehen
sive
mem
ber
eval
uatio
n at
atim
e ag
reed
upo
n by
clu
b m
embe
rs. S
uch
eval
uatio
ns a
rede
sign
ed to
hel
p yo
u ev
alua
te w
hat y
ou le
arne
d as
wel
l as
your
gro
wth
as
a 4-
H m
embe
r.M
embe
rs w
ho ta
ke p
art i
nth
is le
vel o
f eva
luat
ion
can
rece
ive
spec
ial m
embe
rshi
pan
d pr
ojec
t ach
ieve
men
t aw
ards
like
rib
bons
, pin
s an
dce
rtifi
cate
s.
In a
dditi
on, y
ou m
ay w
ant t
o ta
ke p
art i
n co
unty
proj
ect j
udgi
ng. H
owev
er, t
his
leve
l of e
valu
atio
n de
ter-
min
es "
how
wel
l" yo
u di
d on
you
r pr
ojec
t by
assi
gnin
gyo
u a
"pro
ject
gra
de."
You
will
als
o be
com
pare
d ag
ains
tth
e ac
hiev
emen
ts o
f oth
ers
in o
rder
to d
eter
min
e "t
hebe
st"
in y
our
proj
ect a
rea,
as
wel
l as
poss
ible
sta
te fa
irpa
rtic
ipat
ion.
For
mor
e in
form
atio
n re
fer
to 4
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embe
r R
ecog
nitio
n P
rogr
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ntac
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cal
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on o
ffice
for
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ific
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ty p
roje
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for-
mat
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0,..4
F1 4
(41
ifN
NN
NN
NN
NN
NN
NN
NN
tN
et.s
'A
gate
!
II ta
t
TH
E
UM
V,IC
ITY
1 5
7S
CIE
NC
E F
UN
WIT
H E
LEC
TR
ICIT
Y
Whe
n an
y tw
odi
ffere
nt m
ater
ials
com
e in
to c
onta
ct,
tiny
part
icle
s of
elec
tric
ity c
alle
d"e
lect
rons
" m
ove
from
one
to th
eot
her.
Thi
s gi
ves
both
mat
eria
ls a
nel
ectr
ic c
harg
e.O
bjec
ts th
at g
ain
elec
tron
s be
com
ene
gativ
e w
hile
obje
cts
that
lose
elec
tron
s be
com
e
posi
tive.
1 6
ST
AT
K E
LEC
TR
IMY
The
sim
ple
act o
f flic
king
a s
witc
h to
turn
on
a la
mp
in
a da
rk r
oom
is th
ere
sult
of c
entu
ries
of in
vest
igat
ion
and
expe
rimen
tatio
n. T
he s
cien
ce o
f ele
ctric
ity,
the
pow
er th
at
light
s an
d he
ats
our
hom
es, o
pera
tes
com
plex
mac
hine
ryan
d pr
oduc
es c
onve
nien
ce a
nd e
nter
tain
men
tfor
mill
ions
of p
eopl
e, b
egan
mor
e th
an 2
,000
yea
rs a
go in
anci
ent
Gre
ece.
The
re, a
sci
entis
t by
the
nam
e of
Tha
les
of
Mile
tus,
bor
n in
640
BC
, obs
erve
d an
unus
ual p
rope
rty
of
ambe
r, a
pla
stic
type
of m
ater
ial c
omm
only
used
for
jew
elry
. Whe
n ru
bbed
bris
kly
with
fur,
the
ambe
r w
ould
attr
act b
its o
f clo
th, w
ool a
nd fu
r.
Wha
t the
Gre
eks
obse
rved
was
som
ethi
ng c
alle
d"s
tatic
ele
ctric
ity."
"S
tatic
" m
eans
"st
ill,"
or
"not
mov
ing.
"T
his
early
Gre
ek d
isco
very
als
o pr
ovid
ed th
eba
sis
for
the
wor
d "e
lect
ricity
." T
heir
nam
e fo
r am
ber
was
"ele
ctro
n."
Try
Exp
erim
ents
1 &
2 to
exp
lore
this
dis
cove
ry.
Tim
elin
e
8 SC
IEN
CE
FU
N W
ITH
ELE
CT
RIC
ITY
640
BC
Ma
les
of M
iletu
s di
scov
ers
stat
ic e
lect
ricity
.
. Exp
erim
ent
1
CH
AR
GE
A B
ALL
OO
NT
ry th
is e
xper
imen
t to
obse
rve
stat
ic e
lect
ricity
at
wor
k.
You
will
nee
d:.
Rub
ber
ballo
onP
iece
of w
ool o
r fu
r
Infla
te th
e ba
lloon
, tie
its
neck
sec
urel
yan
d ru
b it
:qu
ickl
y ag
ains
t a p
iece
ofw
ool.
Now
hol
d th
eba
lloon
aga
inst
the
wal
l. It
will
stic
k.
. .E
xpla
natio
n.
.R
ubbi
ng th
e ba
lloon
rem
oved
som
eof
the
free
elec
tron
s fr
om th
e w
ool.
Thi
s ga
ve th
e ba
lloon
ane
gativ
e ch
arge
and
the
woo
l a p
ositi
vech
arge
.W
hen
the
char
ged
ballo
on w
as b
roug
ht in
con
tact
with
the
unch
arge
d w
all,
it ex
chan
ged
elec
tron
s w
ith
the
wal
l, ca
usin
g it
to s
tick.
Que
stio
n. .
Exp
lain
wha
t hap
pens
whe
n yo
u ge
t"s
tatic
a
"sh
ock
in th
e w
inte
r af
ter
wal
king
acr
oss
a ca
rpet
edar
ea. W
hy d
oes
this
hap
pen
mor
ein
the
win
ter
than
in th
e su
mm
er?
Wha
t typ
e of
cha
rge
are
you
givi
ng
off,
nega
tive
or p
ositi
ve?
9el
,
1 7
EX
PE
RIM
EN
T 2
ST
AT
IC E
LEC
TR
ICIT
Y L
IGH
TT
ry th
is e
xper
imen
tel
ectr
icity
.
Y o
u w
ill n
eed:
Flu
ores
cent
tube
Pie
ce o
f woo
lD
ark
room
Exp
lana
tion
The
fric
tion
betw
een
the
woo
l and
the
glas
s tu
beca
used
ele
ctro
ns to
str
ike
and
disl
odge
ele
ctro
ns fr
omat
oms
in th
e ga
s in
side
the
tube
. Whe
n th
ese
dis-
lodg
ed e
lect
rons
try
to g
et b
ack
into
thei
r at
oms,
they
give
off
ultr
avio
let r
ays.
The
se r
ays
strik
e a
phos
phor
coat
ing
on th
e in
side
of t
he g
lass
tube
,w
hich
cau
ses
the
coat
ing
to o
bser
ve th
e po
wer
of s
tatic
:
In a
dar
k ro
om, r
apid
ly r
ub th
e tu
be w
ith th
ew
ool c
loth
as
show
n be
low
. The
tube
will
try
tolig
ht.
to g
low
.
It w
asn'
t unt
il 16
00 th
atpr
actic
al p
rogr
ess
bega
n w
ithst
atic
ele
ctric
ity. I
n th
at y
ear,
Eng
lish
phys
icia
n W
illia
mG
ilber
t des
crib
ed th
e st
atic
attr
actio
n in
am
ber.
Lat
erth
at c
entu
ry (
1663
), O
ttoV
an G
ueric
ke b
uilt
one
of th
e
Fig
. 2 S
tatic
elec
tric
ity m
achi
ne
first
sta
tic e
lect
ricm
achi
nes.
Thi
s w
as fo
llow
ed in
174
5 by
the
inve
ntio
n of
the
Leyd
en J
ar b
y D
utch
mat
h-em
atic
ian
nam
ed P
iete
r va
n M
ussc
henb
roek
He
cove
red
a th
in g
lass
jar
insi
de a
nd o
utw
ith m
etal
foil.
Thr
ough
the
wra
ppin
g, h
ein
sert
ed a
bra
ss r
od w
ith a
hoo
k at
top.
Ach
ain
prov
ided
con
tact
with
the
inne
r fo
ilan
d th
e gr
ound
. Mus
sche
nbro
ek fo
und
the
devi
ce w
ould
sto
re e
lect
rical
cha
rges
. Thi
sw
as a
ver
y im
port
ant d
isco
very
bec
ause
befo
re th
is ti
me
no m
etho
d ha
d be
en fo
und
for
stor
ing
stat
ic c
harg
es.
14"
Fig
. 3 L
eyde
n Ja
rS
tore
s el
ectr
ical
cha
rges
An
equa
lly im
port
ant d
isco
very
occu
rred
in 1
787
by a
n E
nglis
h sc
ient
ist
nam
ed A
brah
am B
enne
t. In
that
yea
rB
enne
t per
fect
ed w
hat h
e ca
lled
the
"ele
ctro
scop
e."
An
elec
tros
cope
has
two
strip
s of
met
al fo
il ha
ngin
g in
side
a g
lass
vess
el. A
cha
rged
am
ber
rod
touc
hing
the
met
al b
all o
n to
p of
the
inst
rum
ent c
ause
sth
e le
aves
to r
epel
eac
h ot
her.
Thi
sin
stru
men
t was
use
ful f
or d
eter
min
ing
the
pres
ence
of e
lect
rost
atic
cha
rges
as
wel
las
det
erm
inin
g th
e po
larit
y of
the
char
ges.
Fig
. 4E
lect
rosc
ope
1296
AD
Pet
rus
Per
egrin
us d
isco
vers
prop
ertie
s of
mag
netis
m.
1 8
1600
The
wor
d "e
lect
ricity
" co
ined
from
the
Gre
ek w
ord
"ele
ctro
n" b
y W
illia
m G
ilber
t.
1663
1 9
Otto
Van
Gue
ricke
bui
lds
the
first
sta
tic e
lect
ric m
achi
ne.
9S
CIE
NC
E F
UN
WIT
H E
LEC
TR
ICIT
Y
Insi
de th
e ba
ttery
isa
carb
on r
od a
ndzi
nc c
onta
iner
topr
oduc
e an
ele
ctric
char
ge. A
cur
rent
flow
s if
the
rod
and
cont
aine
r ar
eco
nnec
ted.
Whe
nth
e ch
amic
als
are
used
up,
the
batte
rygo
es d
ead.
Car
bon
rod
Che
mic
als
Zin
cco
ntai
ner Fi
g. 5
Zin
c ca
rbon
bat
tery
10
-C
UR
RE
NT
ELE
CT
RIC
ITY
In 1
786,
Lui
gi G
alva
niob
serv
ed h
ow a
frog
's le
gs
mov
ed w
hen
expo
sed
to a
str
ong
stat
ic c
harg
e.H
e al
so
obse
rved
that
whe
n he
touc
hed
the
legs
with
cop
per
and
zinc
inst
rum
ents
, the
y al
som
oved
. He
conc
lude
a th
at th
e
actio
n ha
d so
met
hing
to d
o w
ithth
e "s
tatic
ele
ctric
ity
trap
ped
in th
e fr
og."
Alth
c 'g
h hi
s co
nclu
sion
was
wro
ng,
his
wor
k m
ade
othe
r sc
ient
ists
aw
are
of th
is u
nusu
al
occu
rren
ce.
In80
0, A
less
andr
o V
olta
, an
Italia
n ph
ysic
s pr
ofes
sor
disc
over
ed w
hy th
e fr
og's
legs
mov
ed. H
edc
,Irm
ined
that
Gal
vani
's d
isco
very
was
a n
ew fo
rmof
ele
ctric
ity w
hich
he c
alle
d "c
urre
nt e
lect
ricity
." T
his
type
of e
lect
ricity
was
gene
rate
d fr
om th
e ch
emic
alac
tion
of m
oist
ure
in th
e fr
ogco
uple
d w
ith th
e co
pper
and
zinc
inst
rum
ents
.
Fur
ther
exp
erim
enta
tion
led
Vol
ta to
pro
duce
the
first
sour
ce o
f con
tinuo
us c
urre
ntel
ectr
icity
--
the
batte
ry.
He
mad
e it
of s
tack
ed c
oppe
r an
d
zinc
pla
tes
sepa
rate
d by
pap
eror
clo
th th
at h
adbe
en s
oake
d
in a
sal
t sol
utio
n. T
his
early
sour
ce o
f bat
tery
pow
er w
asre
ferr
ed to
as
a "v
olta
ic c
ell."
Try
Exp
erim
ent 3
and
the
two
Dig
ging
Dee
perA
ctiv
ities
to
expl
ore
this
dis
cove
ry.
2017
29S
teph
en G
ray
disc
over
s th
e id
eaof
con
duct
ors
vs n
on-c
ondu
ctor
s.
SC
IEN
CE
FU
N W
ITH
ELE
CT
RIC
ITY
Fig.
6 V
olta
ic c
ell
Exp
erim
ent 3
if.it ir
Ton
gue
Tes
tni
kik,
4kM
ake
and
test
you
r(
'464
.41.
,
own
sour
ce o
fele
ctro
-
chem
ical
ele
ctric
ity.
: You
will
nee
d:1
zinc
car
bon
batte
ry (
gene
ral p
urpo
sety
pe)
Cop
per
penn
y (B
est
if m
inte
d be
fore
198
0 du
e to
high
cop
per
cont
ent)
Han
d to
ols
With
hel
p fr
om a
n ad
ult,
take
apa
rt a
zinc
c..r
bon
batte
ry. W
ash
the
cont
aine
r th
orou
ghly
.P
lace
the
cont
aine
r an
d th
ecl
ean
copp
er p
enny
on
your
tong
ue. T
ouch
the
coin
and
con
tain
er to
geth
er.
You
will
feel
a ti
nglin
g se
nsat
ion.
Mov
eth
em a
part
and
it
stop
s.
Exp
lana
tion
The
con
tain
er is
mad
e of
zin
c.if
zinc
and
cop
per
are
plac
ed in
sal
ty w
ater
and
conn
ecte
d to
geth
er, a
smal
l ele
ctric
cur
rent
flow
s be
twee
nth
em. Y
our
saliv
a is
slig
htly
sal
ty, s
o th
e co
inan
d co
ntai
ner
prod
uce
a w
eak
curr
ent.
You
feel
this
cur
rent
be-
.ca
use
your
tong
ue is
ver
yse
nsiti
ve.
5
1733
Cha
rles
Du
Fay
dis
cove
rs th
at li
kech
arge
s re
pel a
nd u
nlik
e at
trac
t.
2 1
1745
Pie
ter
Van
Mus
sche
nbro
ck d
evel
ops
the
Leyd
enJa
r;
stat
ic e
lect
ricity
can
now
be
built
up
and
stor
ed.
Dig
ging
Dee
per
GE
TT
ING
ELE
aRIC
ITY
FR
OM
A L
EM
ON
Try
mak
ing
elec
tric
ity fr
om a
nat
ural
pow
er s
ourc
e.
You
will
nee
d:Le
mon
Pap
er c
lip12
feet
22-
gaug
e in
sula
ted
wire
, sin
gle
stra
nd
Ano
ther
form
of a
vol
taic
cel
l can
be
mad
e by
usi
ng a
lem
on. T
his
cell
cons
ists
of t
wo
elec
trod
es, s
epar
ated
and
imm
erse
d in
an
elec
trol
yte.
Tw
o di
ffere
nt m
ater
ials
are
used
for
the
elec
trod
es s
o th
e el
ectr
olyt
e (le
mon
juic
e)w
ill a
ct m
ore
on o
ne e
lect
rode
than
it d
oes
on th
e ot
her
and
prod
uce
a po
tent
ial d
iffer
ence
bet
wee
n th
em.
Her
e is
how
to m
ake
the
cell:
Rol
l the
lem
on o
n a
hard
sur
face
with
you
r pa
lm to
bre
ak u
p so
me
of th
etis
sue.
Str
aigh
ten
the
pape
r cl
ip, a
nd p
ush
it ab
out h
alf
way
into
the
lem
on. C
lean
the
insu
latio
n of
f the
wire
, and
push
it in
to th
e le
mon
nea
r th
e pa
per
clip
. 13o
th w
ires
shou
ld b
e cl
ose
to e
(. .,
n ot
her
but s
houl
d no
t be
touc
hing
insi
de o
r ou
tsid
e th
e le
mon
. If y
ou h
ave
any
diffi
culty
inse
rtin
g th
e w
ire, f
irst m
ake
a ho
le w
ith th
e pa
per
clip
so
it m
ay b
e in
sert
ed m
ore
easi
ly.
To
find
whe
ther
the
lem
on is
a s
ourc
e of
ele
ctric
ity,
touc
h yo
ur to
ngue
to th
e en
ds o
f the
two
wire
s th
at c
ome
A 1750
Ben
Fra
nklin
giv
es +
and
desi
gnat
ions
to e
lect
ricity
and
inve
nts
light
ning
rod
.
'2
Str
ippe
d co
pper
wire
Lem
on, o
rang
e or
gra
pefr
uit
Ope
ned
out p
aper
clip
from
the
lem
on. Y
ou w
ill ta
ste
slig
ht a
cidi
ty. Y
ou m
ayev
en fe
el a
slig
ht ti
nglin
g. T
his
is th
e sa
me
sens
atio
n yo
uca
n ex
perie
nce
by to
uchi
ng y
our
tong
ue to
the
term
inal
sof
a 9
vol
t (tr
ansi
stor
) ba
ttery
. You
may
als
o tr
y th
is e
xper
i-m
ent w
ith a
n or
ange
or
any
othe
r ci
trus
frui
t.
1786
Gal
vani
inad
vert
ently
dis
cove
rs "
curr
ent
elec
tric
ity"
whi
le e
xper
imen
ting
with
frog
.
1.
In 1
750,
Ben
Fra
nklin
orig
inat
edth
e te
rms
"pos
itive
"an
d "n
egat
ive"
for
elec
tric
al p
olar
ity.
He
is s
aid
to h
ave
ci s
cove
rod
the
bi.
pole
OM
nat
ure
ofel
ectr
icity
dur
ing
his
expe
rimen
ts w
ithlig
htni
ng. H
islig
htin
g ex
perim
ents
also
led
way
to h
isin
vent
ion
of th
elig
htni
ng r
od.
<M
11S
CIE
NC
E F
UN
WIT
H E
LEC
TR
ICIT
Y
Ele
ctric
ity c
an a
lso
be g
ener
ated
from
heat
and
is c
alle
dth
erm
oele
ctric
itv.
Inle
t, T
hom
as J
.S
eebe
ck, a
Ger
man
phys
icis
t, ob
serv
edth
at a
n el
ectr
iccu
rren
t is
gene
rate
d w
hen
copp
er a
nd ir
onw
ires
are
join
edan
d th
eir
junc
tion
poin
t hea
ted.
ELE
CT
RO
N F
LOW
Cop
per
wire
e,,,*
" To
cKen
t det
ecto
r
Dig
ging
Dee
per
PO
IAR
ITY
IND
ICA
TO
RP
ositi
veN
egat
ive
term
inal
term
inal
Tes
t to
see
if th
e +
and
-m
arki
ngs
on y
our
batte
ryar
e co
rrec
t.
Iron
wire
ELE
CT
RO
N F
LOW
12
Bub
bles
You
will
nee
d:O
ne p
otat
oF
our
feet
22-
gaug
e in
sula
ted
1 6-
volt
lant
ern
batte
ry
Som
etim
es it
may
be
nece
ssar
y to
det
erm
ine
the
pola
rity
of a
sto
rage
bat
tery
, suc
h as
one
in a
n au
tom
obile
or b
oat,
beca
use
the
mar
king
s ha
vebe
com
e ob
scur
ed.
Whe
n th
is h
appe
ns, a
pot
ato
may
be
used
.
Slic
e th
e po
tato
in h
alf.
Con
nect
lead
s fr
om b
oth
term
inal
s of
the
batte
ry to
the
pota
to a
s ill
ustr
ated
. Put
the
wire
s ab
out o
ne in
ch a
part
so
that
they
do
not t
ouch
insi
de o
r ou
tsid
e of
the
pota
to. A
lso
mak
e su
re th
e pa
rt o
fea
ch w
ire w
hich
goe
s in
to th
e po
tato
has
all
the
insu
latio
n
rem
oved
.
Pot
ato
Gre
enis
hco
lor
wire
, sin
gle
stra
nd
In a
sho
rt ti
me,
gre
en d
isco
lora
tion
will
be
notic
edar
ound
one
of t
he w
ires.
At t
he s
ame
time
ther
e m
ay b
eso
me
bubb
ling
(or
no in
dica
tion
of a
ny a
ctiv
ity a
tal
l) at
the
othe
r w
ire. T
he d
isco
lora
tion
is a
roun
d th
e le
ad g
oing
/ to
the
nega
tive
term
inal
. The
oth
er w
ire, w
here
the
Fig
, 9 T
herm
oele
ctric
itybu
bble
s ap
pear
, goe
s to
the
posi
tive
term
inal
.
2417
87B
enne
t inv
ents
"el
ectr
osco
pe"
to d
etec
tpo
larit
y of
sta
tic e
lect
ric c
harg
es.
SC
IEN
CE
FU
N W
ITH
ELE
CT
RIC
ITY
1800
Vol
ta's
inve
ntio
n of
firs
t pra
ctic
alst
orag
e ba
ttery
, the
"V
olta
ic P
ile."
3E
LEC
TR
OM
AG
NE
TIS
MT
he e
ffect
s of
Vol
ta's
dis
cove
ry o
n th
e sc
ient
ific
wor
ldw
ere
imm
edia
te. A
t las
t, sc
ient
ists
had
a co
ntin
uous
sour
ce o
f ele
ctric
ity w
ithw
hich
to w
ork.
In 1
819,
,D
anis
h sc
ient
ist,
Han
s C
hris
tian
Oer
sted
, dis
cove
red
that
. Exp
erim
ent 4
MA
GN
ET
IC F
IELD
AR
OU
ND
AC
UR
RE
NT
CA
RR
YIN
G W
IRE
Try
this
sim
ple
expe
rimen
t to
see
how
a c
urre
ntca
rryi
ng w
ire g
ives
off
a m
agne
tic fi
eld.
You
will
nee
d:W
ire h
ange
rC
ardb
oard
Com
pass
2 fe
et o
f 22-
gaug
e in
sula
ted
wire
, sin
gle
stra
nd1
6-vo
lt la
nter
n ba
ttery
Mak
e a
stan
d fr
om a
wire
han
ger
as il
lust
rate
d in
Fig
ure
10. S
crap
e th
e co
atin
g of
f the
han
ger
for
abou
tan
inch
at e
ither
end
. Cut
a p
iece
of c
ardb
oard
at l
east
eigh
t inc
hes
squa
re w
ith a
hol
e in
the
mid
dle
and
draw
thre
e co
ncen
tric
circ
les
on it
. The
se s
houl
d be
spa
ced
abou
t one
inch
apa
rt w
ith th
e in
ner
circ
le a
bout
two
inch
es fr
om th
e w
ire. C
ente
r th
e bo
ard
on th
e st
and
soit
stay
s ab
out h
alf w
ay u
p w
ithou
t slip
ping
. A li
ttle
tape
will
hel
p ho
ld it
in p
ositi
on.
*
1808
Dum
phry
Dav
y cr
eate
s "a
rc li
ght"
from
a r
efle
cted
spa
rk.
1819
25O
erst
ed d
isco
vers
mag
netic
fiel
dis
cau
sed
by e
lect
ric c
urre
nt.
a co
mpa
ss h
eld
near
a w
ire c
arry
ing
curr
ent f
rom
aba
ttery
wou
ld m
ove
the
need
le. T
his
was
the
disc
over
y of
elec
trom
agne
tism
. Try
exp
erim
ent 4
to fu
rthe
r ex
plor
e th
is
disc
over
y.
OO
OO
OO
Com
pass
on
card
boar
d
Fig
. 9
Stif
f cop
per
wire
or c
oat h
ange
r
Loos
ew
ire
Con
nect
the
stan
d w
ith a
wire
to o
ne te
rmin
al o
f the
batte
ry a
s sh
own.
Lay
the
com
pass
on
any
snot
on
the
first
circ
le a
nd c
onne
ct th
e lo
ose
wire
to th
e ot
her
batte
ryte
rmin
al. T
he c
ompa
ss n
eedl
e w
ill a
lign
itsel
f with
the
circ
le. T
ry m
ovin
g th
e co
mpa
ss to
diff
eren
t spo
ts o
n th
eci
rcle
or
othe
r ci
rcle
s.
Han
s C
hris
tian
Oer
sted
'sE
lect
rom
agne
tism
exp
erim
ent
Exp
lana
tion
The
res
ults
of t
his
expe
rimen
t ind
icat
e th
atth
e di
rect
ion
of th
e m
agne
tic fi
eld
is c
onst
ant.
the
mag
netic
fiel
d is
loca
ted
all a
roun
d th
e w
ire.
the
mag
nec
field
spr
eads
from
the
cent
er s
imila
rth
e pa
ttern
whi
ch fo
rms
whe
n a
pebb
le is
thro
wn
into
a la
ke.
Que
stio
nW
hat w
ould
hap
pen
to th
e st
reng
th o
f the
ele
ctro
mag
-ne
tic fi
eld
if th
e w
ire w
as lo
oped
thro
ugh
two
or m
ore
times
and
then
con
nect
ed to
the
batte
ry?
vO
OO
O
Nat
ural
mag
nets
calle
d lo
adst
ones
or
lead
ing
ston
es w
ere
used
by
early
expl
orer
s to
find
thei
r w
ay o
n se
avo
yage
s. T
he G
reek
sdi
scov
ered
this
mag
netic
roc
k ne
arth
e ci
ty o
f Mag
nesi
a.T
hey
nam
ed th
ero
ck "
mag
netit
e" fo
rth
e ci
ty.
A 1820
And
re A
mor
e di
scov
ers
rela
tions
hip
betw
een
elec
tric
ity a
nd m
agne
tism
. n 4
1821
Far
aday
sho
ws
that
ele
ctric
ene
rgy
coul
dbe
con
vert
ed in
to m
echa
nica
l mot
ion.
A 1821
See
beck
dis
cove
rs th
at e
lect
ric c
urre
nt c
an b
e pr
oduc
ed27
13w
hen
two
diss
imila
r m
etal
s ar
e jo
ined
and
hea
ted.
SC
IEN
CE
FU
N W
ITH
ELE
CT
RIC
ITY
Oer
sted
's d
isco
very
sho
ws
a di
rect
rel
atio
nshi
pbe
twee
n el
edric
ity a
ndm
agne
tism
. Thi
s w
as a
impo
rtan
t, be
caus
eth
e
only
sou
rce
of m
agne
tism
befo
re th
at ti
me
was
from
natu
ral m
agne
ts c
alle
dlo
adst
ones
. Bas
ed o
n
Oer
sted
's fi
nd, a
n in
stru
-m
ent c
alle
d a
Gal
vans
cope
was
soo
n pe
rfec
ted
to
dete
ct e
lect
rom
agne
ticcu
rren
t. T
ry E
xper
imen
t 5to
furt
her
expl
ore
this
disc
over
y.
.E
xper
imen
t 5
. MA
KE
A G
ALV
AN
SC
OP
EM
ake
a ga
lvan
scop
e to
furt
her
expl
ore
the
rela
tion-
ship
bet
wee
n el
ectr
icity
and
mag
netis
m.
You
will
nee
d:C
ompa
ssF
lash
light
bat
tery
3 x
4-in
ch p
iece
of c
ardb
oard
10 fe
et o
f 22-
gaug
e in
sula
ted
wire
, sin
gle
stra
nd
Fol
d tw
o en
ds o
f the
car
dboa
rd to
form
for
the
wire
, the
n w
rap
the
wire
aro
und
the
card
boar
d
abou
t 30
times
(F
igur
e 13
.1).
Lea
veab
out a
foot
of
OO
OO
555
If
surp
lus
wire
for
conn
ectio
ns. S
crap
eab
out a
hal
f an
inch
of t
he in
sula
tion
from
eac
hen
d of
the
wire
. Pla
ce
the
com
pass
on
the
card
boar
dan
d be
neat
h th
e w
ire a
s
show
n in
Fig
ure
13.2
. Tur
n th
eca
rdbo
ard
so th
e w
ires
run
east
and
wes
t the
n co
nnec
tthe
m to
the
batte
ry
(Fig
ure
13.3
). W
hen
the
ends
of t
he w
ires
are
con-
nect
ed to
the
batte
ry, t
he c
ompa
ssne
edle
will
be
defle
cted
nea
rly e
ast a
nd w
est,
show
ing
the
curr
ent
flow
. Thi
s m
ovem
ent i
ndic
ates
the
pres
ence
of a
n
elec
trom
agne
tic fi
eld
with
in th
e co
il.
111
Fig
. 13.
1 W
rap
the
wire
aro
und
the
card
boar
d an
d re
mov
e th
ein
sula
tion
from
the
ends
.
Fig
. 13.
2 P
lace
the
com
pass
insi
deth
eco
il of
wire
. Alig
n th
e w
ires
east
and
wes
t.
Fig
. 13.
3 T
ouch
the
wire
s to
the
batte
ryan
d w
atch
the
com
pass
nee
dle.
Als
o tty
reve
rsin
g th
e w
ires
to s
ee w
hat h
appe
ns.
14.
SC
IEN
9EF
UN
WIT
H E
LEC
TR
ICIT
Y
r)8
1825
Will
iam
Stu
rgeo
n in
vent
sth
e el
ectr
omag
net.
1827
Geo
rge
Ohm
dis
cove
rs r
elat
ion
betw
een
curr
ent,
volta
ge a
nd r
esis
tanc
e.n
4.
1831
Far
aday
dis
cove
rs g
ener
atio
n of
elec
tric
ity b
y us
e of
"D
isk
Dyn
amo.
"
4E
LEC
TR
OM
AG
NE
T1.
1111
1111
111
With
out q
uest
ion,
the
grea
test
imm
edia
te p
ract
ical
appl
icat
ion
of O
erst
ed's
dis
cove
ry (
elec
trom
agne
tism
,18
19)
was
the
even
tual
inve
ntio
n of
the
elec
trom
agne
t.T
his
was
acc
ompl
ishe
d in
182
5, w
hen
Will
iam
Stu
rt, o
nof
Woo
lrich
, Eng
land
wou
nd c
oppe
r w
ire a
roun
d a
bar
ofiro
n an
d m
ade
the
first
ele
ctro
mag
net.
Thi
s in
vent
ion
mad
e th
e te
legr
aph,
ele
ctric
gen
erat
or, a
nd th
e el
ectr
icm
otor
pos
sibl
e. H
is m
agne
t was
mad
e fr
om a
sof
t iro
n ba
rab
out 1
2-in
ches
long
and
1/2
-inch
in d
iam
eter
ben
t int
o a
"U"
shap
e. T
ry E
xper
imen
t 4 a
nd th
e D
iggi
ng D
eepe
r to
furt
her
expl
ore
this
inno
vatio
n.
Exp
erim
ent 6
MA
KE
AN
ELE
CT
RoM
AG
NE
TE
xper
ienc
e th
e po
wer
of a
n el
ectr
omag
net.
You
will
nee
d:M
agne
t wire
hel
dLa
rge
nail
(abo
ut th
ree
inch
es lo
n,4)
in p
lace
with
tape
1 6-
volt
lant
ern
batte
ry4
feet
of 2
2-ga
uge
insu
late
d w
ire, s
ingl
e st
rand
Leav
ing
a fe
w in
ches
of w
ire fo
r a
lead
, wra
p ab
out 5
0 tim
esar
ound
the
nail
as s
how
n in
Fig
ure
14.1
. Lea
ve a
littl
e w
ire a
t the
end
for
anot
her
lead
. Whe
n th
e en
ds o
f the
coi
l are
con
nect
ed to
a b
atte
ry,
the
elec
trom
agne
t can
pic
k up
sm
all n
ails
and
pap
er c
lips.
11
Dig
ging
Dee
per
__
PO
LAR
ITY
CH
EC
KC
heck
the
pola
rity
ofyo
ur e
lect
rom
agne
t with
aco
mpa
ss. H
old
your
ele
c-tr
omag
net o
ne to
two
inch
es fr
om th
e co
mpa
ss a
ssh
own
in F
igur
e 14
.2. R
e-m
ove
the
nail
and
rech
eck
the
pola
rity.
Not
e th
e di
f-fe
renc
e in
the
defle
ctio
ntim
e of
the
com
pass
. Whe
nth
e na
il w
as in
pla
ce, a
llth
e av
aila
ble
mag
netic
stre
ngth
was
funn
eled
inan
d ar
ound
the
nail.
P2r
6 5
43
1
Fig
. 14.
2 T
ap o
n te
rmin
al a
ndw
atch
ele
ctro
mag
net a
ttrac
tne
edle
Fig
. 14.
1 M
agne
t wire
held
in p
lace
with
tape
Pin
s or
tack
s
*183
3Jo
seph
Sax
on o
f Eng
land
inve
nts
first
AC
gen
erat
or.
3 0
*183
4W
illia
m S
turg
eon
perf
ects
DC
gen
erat
orth
roug
h in
vent
ion
of s
plit
ring
com
mut
ator
.
Usi
ng a
bat
tery
oper
ated
elec
trom
agne
t,S
amue
l Mor
sein
vent
ed th
ete
legr
aph
in 1
837.
The
firs
t lon
gdi
stan
ce te
legr
aph
mes
sage
, "W
hat h
ath
God
wro
ught
?" w
asse
nt fr
om th
e U
.S.
Sup
rem
e C
ourt
inW
ashi
ngto
n D
.C. o
nM
ay 2
4, 1
844
toB
altim
ore
MD
.
re-
In a
n ea
rly M
orse
tele
grap
h,le
ctro
mag
netic
coi
ls (
1) w
ere
ener
gize
d by
a c
urre
nt p
ulse
tran
smitt
ed th
roug
h a
tele
grap
hlin
e (2
). T
he c
oits
attr
acte
d a
leve
r (3
) th
at p
ress
ed a
n in
ked
rolle
r (4
) ag
ains
t a m
ovin
g pa
per
strip
(5)
driv
en b
y a
cloc
kwor
kfli
otor
wou
nd b
y a
hand
le (
6).i
*183
53
1D
aven
port
pat
ent's
the
first
DC
elec
tric
mot
or (
batte
ry-p
ower
ed).
15S
CIE
NC
E F
UN
WIT
H E
LEC
TR
ICIT
Y
Man
-mad
e m
agne
tsar
e al
umin
um,
nick
el a
nd c
obal
t(a
lnic
o). O
nce
elec
trom
agne
tical
lych
arge
d th
isex
trem
ely
hard
met
al w
ill r
emai
npe
rman
ently
mag
netiz
ed,
outla
stin
g so
fter
stee
l mag
nets
.
16
Dig
ging
Dee
per
MA
GN
ET
IZE
A S
CR
EW
DR
IVE
RU
se e
lect
rom
agen
tisim
to m
agne
tize
asc
rew
driv
er.
You
wiii
nee
d:6-
voit
lant
ern
batte
ryS
crew
driv
er25
feet
of 2
2-ga
uge
insu
late
d w
ire,
sing
le s
tran
d
Leav
e a
leng
th o
f wire
for
a le
ad, t
hen
wra
pth
e w
ire
arou
nd th
e sh
ank
of th
e sc
rew
driv
er in
eve
n co
ils(F
igur
e
15.1
). U
se a
ll th
e w
ire e
xcep
t for
ano
ther
shor
t len
gth
for
a le
ad. R
emov
e th
ein
sula
tion
from
the
ends
of t
he le
ads
(Fig
ure
15.2
). B
riefly
touc
h th
e en
ds to
the
term
inal
s of
the
batte
ry (
Fig
ure
1 5.
3). T
his
shou
ld m
agne
tize
the
scre
w-
driv
er.
4111
11IIM
ININ
EX
PLA
NA
TIO
NY
ou h
ave
mad
e a
perm
anen
t mag
net.
The
mag
netic
field
of t
he c
oil a
ligns
the
mol
ecul
esof
the
scre
wdr
iver
into
a m
agne
t. (F
ig. 1
5.6)
(Y
ou c
anac
com
plis
h th
e sa
me
thin
g by
str
okin
g th
e sc
rew
driv
er w
ith a
bar
mag
net i
n a
dow
nwar
d fa
shio
n.)
It w
illre
mai
n rn
agni
tized
for
afe
w h
ours
, day
s or
yea
rsde
pend
ing
on th
e m
ater
ials
from
whi
ch it
was
mad
e.T
he h
arde
r th
e m
ater
ial,
the
long
er it
will
rem
ain
Ell
011
Ell
Ell
Ell
Ell
EU
Ell
Ell
Ell
Ell
Ell
Ell
Ell
011
CI E
l EN
Ell
GM
Fig
. 15.
6
f3cl
ice1
1341
a1fi
rill
ON
Nic
-alV
ilEE
Nm
agne
tized
.F
ig. 1
5.7
To
rem
ove
the
char
ge, t
ry s
trik
ing
the
scre
wdr
iver
with
a ha
mm
er. (
Fig
. 15.
5)T
his
will
jum
ble
the
atom
s th
atw
ere
alig
ned
in th
e m
agne
tizin
g pr
oces
s.(F
ig. 1
5.7)
..."-
al.1
0101
040"
4:1.
110"
.
Fig
. 15.
4 S
crew
driv
er b
ecom
es a
char
ged
mag
net
Fig
. 15.
1 W
rap
wire
Fig
. 15.
2 C
ut, l
eavi
ng a
lead
er
1837
32S
amue
l Mor
se in
vent
s th
e te
legr
aph.
SC
IEN
CE
FU
N W
ITH
ELE
CT
RIC
ITY
Fig
. 15.
3 C
onne
ct th
e w
ire to
bat
tery
Fig
. 15.
5 S
trik
e sc
rew
driv
ier
to d
isen
gage
mag
net
3318
44F
irst l
ong-
dist
ance
tele
grap
h sy
stem
est
ablis
hed
betw
een
Was
hing
ton,
D.C
. and
Bal
timor
e, M
d.
5E
LEC
TR
ICG
EN
ER
AT
ION
In 1
831,
whi
le u
sing
a ty
pe o
f gal
vans
cope
, a y
oung
scie
ntis
t nam
ed M
icha
el F
arad
ay m
ade
an im
port
ant
disc
over
y. H
e fo
und
that
a m
ovin
g m
agne
t wou
ld in
duce
an e
lect
ric c
urre
nt in
the
coil
of h
is g
alva
nsco
pe.
Far
aday
's d
isco
very
led
to th
e ra
pid
deve
lopm
ent o
f the
"dyn
amo
elec
tric
mac
hine
" or
the
elec
tric
gen
erat
or.
The
se e
arly
gen
erat
ors
prod
uced
a s
impl
e di
rect
cur
rent
ION
E W
AY
> D
.C. C
urre
nt
- E
xper
imen
t 7 ..
......
......
......
IND
UC
E C
UR
RE
NT
FR
OM
A M
AG
NE
TU
se y
our
galv
anos
cope
to te
st th
e pr
esen
ce o
fel
ectr
icity
that
you
cre
ate.
S
0You
win
nee
d:B
ar m
agne
t10
feet
of 2
2-ga
uge
insu
late
d w
ire, s
ingl
e st
rand
(bel
l wire
)G
alva
nosc
ope
(DC
) lik
e th
at o
f a b
atte
ry.
Thi
s m
eant
that
cur
rent
flow
ed in
the
sam
e di
rec-
tion;
pos
itive
alw
ays
rem
aine
d po
sitiv
e an
d ne
gativ
e al
way
s re
mai
ned
nega
tive.
Late
r ge
nera
tors
pro
duce
d an
alte
rnat
ing
curr
ent (
AC
). T
his
mea
nt th
at th
e cu
rren
t wen
t bac
k an
d fo
rth,
alte
rnat
ing
the
pola
rity
of th
e po
les.
Thi
s al
low
ed e
lect
ricity
to b
e tr
ans-
mitt
ed o
ver
long
er d
ista
nces
. Try
Exp
erim
ent 7
and
the
Dig
ging
Dee
per
Act
ivity
to e
xplo
re th
is d
isco
very
furt
her.
<U
P D
OW
N>
A.C
. Cur
rent
.W
rap
the
wire
aro
und
your
fing
ers
abou
t 30
times
tom
ake
a co
il as
sho
wn
in F
igur
e 17
.1. I
t sho
uld
be a
littl
ela
rger
than
the
bar
mag
net.
Leav
e a
leng
th fr
ee a
t eac
h en
dto
mak
e co
nnec
tions
. Rem
ove
ahou
t a h
alf i
nch
of th
ein
sula
tion
on e
ach
end
and
conn
ect t
hem
to th
e ga
lvan
om-
eter
(se
e F
igur
e 17
.2).
Mov
e th
e ba
r m
agne
t abr
uptly
in a
ndou
t of t
he c
ente
r of
the
coil
as s
how
n in
Fig
ure
17.3
.
Not
ice
the
dire
ctio
n of
the
mov
emen
t of t
he n
eedl
e.W
hen
the
mag
net i
s fir
stpu
shed
into
the
coil,
the
need
le is
def
lect
ed in
one
dire
ctio
n. W
hen
the
mag
net i
s re
mov
ed, i
tm
oves
in th
e ot
her
dire
c-tio
n. T
he c
urre
nt c
hang
eddi
rect
ions
(F
igur
e 17
.4).
The
cur
rent
can
be
in-
crea
sed
by u
sing
a s
tron
ger
mag
net,
mov
ing
the
mag
net f
aste
r or
add
ing
mor
e lo
ops
in th
e co
il.F
ig.1
71 M
ake
a co
il of
wire
.F
ig. 1
7.2.
Con
nect
the
coil
toth
e co
il w
ith th
e co
mpa
ss.
1850
Man
ufac
turin
g of
wire
by
mac
hine
take
sth
e pl
ace
of "
hand
dra
wn"
met
hods
.3
4
Fig
. 173
Qui
ckly
pus
h th
e m
agne
t int
oth
e co
il an
d w
atch
the
com
pass
nee
dle.
1873
Z'e
nobe
The
ophi
le G
ram
me
dem
onst
rate
dfir
st D
C m
otor
to b
e po
wer
ed b
y a
gene
rato
r.
1875
Ale
xand
er B
ell d
evel
ops
the
elec
tric
tele
phon
e.
In th
e U
nite
d S
tate
s,A
C c
urre
nt m
akes
this
turn
abou
t 60
thne
s ea
ch s
econ
d.T
his
60-c
ycle
stan
dard
allo
ws
elec
tric
clo
cks,
elec
tric
al a
pplia
nces
and
elec
tric
mot
ors
to o
pera
teco
nsis
tent
ly a
cros
sth
e co
untr
y.
Fig
. 17.
4. Q
uick
ly w
ithdr
aw th
em
agne
t and
not
ice
that
the
com
pass
is d
efle
cted
in th
e op
posi
te d
ilect
ion.
S S
S S
I
3 5
17S
CIE
NC
E F
UN
WIT
H E
LEC
TR
ICIT
Y
Whe
n th
e fir
st A
Cge
nera
tor
was
inve
nted
in 1
833
itw
as n
ot fu
llyun
ders
tood
how
itco
uld
be u
sefu
l.
183t
;Dig
ging
Dee
per
AC
/DC
',D
ICT
ION
Try
this
exp
erim
ent t
o se
e fo
r yo
urse
lfho
w A
C a
nd
DC
cur
rent
s di
ffer.
You
will
nee
d:2
teas
poon
s co
rnst
arch
1/2c
up w
ater
2 te
aspo
ons
of p
otas
sium
iodi
de(o
btai
n fr
om p
har-
mac
y, o
r ca
ll N
AS
CO
at
1-80
0-55
8-95
95)
2 m
etal
(no
n-al
umin
um)
pie
pans
8 fe
et b
ell w
ireM
easu
ring
cup
2 6-
volt
lant
ern
batte
ries
AC
trai
n tr
ansf
orm
erC
loth
str
ips
Mix
two
teas
poon
s of
cor
nsta
rch
inth
-cup
of w
ater
.
Add
two
teas
poon
s of
pot
assi
um io
dide
. Soa
kth
e st
rips
of
clot
h in
the
solu
tion.
SC
EN
CE
FU
N W
ITH
ELE
CT
RIC
ITY
1878
Firs
t com
mer
cial
tele
phon
e lin
ese
t up
in S
omer
ville
, Mas
s,
Dire
ct C
urre
ntW
ire th
e ne
gativ
e po
stof
one
bat
tery
to th
e po
sitiv
epo
st o
f the
oth
er b
atte
ry.
Tur
n a
pie
pan
upsi
de d
own,
and
conn
ect a
wire
from
the
free
neg
ativ
e po
st to
the
oute
r rim
of t
he p
late
.S
quee
ze th
e so
lutio
n ou
t of
one
clot
h an
d st
retc
hth
e
clot
h ov
er th
e pl
ate.
Atta
cha
wire
to th
e re
mai
ning
posi
tive
post
. Usi
ng th
e tip
of th
is w
ire a
s a
styl
us, d
raw
it ac
ross
the
clot
h. A
sol
idlin
e w
ill a
ppea
r.
Alte
rnat
ing
Cur
rent
Use
an
AC
trai
n tr
ans-
form
er in
stea
d of
bat
terie
s.A
ttach
a w
ire fr
om th
e lo
w-
volta
ge te
rmin
al to
the
rimof
a p
ie p
late
. Spr
ead
a cl
oth
satu
rate
d in
sol
utio
n on
the
plat
e. C
onne
ct a
wire
to th
eun
used
term
inal
of t
hetr
ansf
orm
er, a
nd p
lug
the
tran
sfor
mer
into
an
elec
tric
outle
t. H
oldi
ng th
e in
sula
ted
part
of t
he fr
ee w
ire, d
raw
the
wire
qui
ckly
acr
oss
the
clot
h. A
bro
ken
line
will
form
.
1879
Cha
rles
Scr
ibne
r in
vent
sth
e kn
ife s
witc
h.3
718
79E
diso
n in
vent
s th
eel
ectr
ic li
ght b
ulb.
ELE
CM
ICM
OT
OR
Imo= N
ow th
at th
e ge
nera
tion
of e
lect
rom
agne
tism
and
relia
ble
elec
tric
cur
rent
had
bee
n di
scov
ered
, inv
ento
rssc
ram
bled
to h
arne
ss th
ese
new
pow
ers.
As
early
as
835,
an A
mer
ican
sci
entis
t nam
ed T
hom
as D
aven
port
pate
nted
the
wor
ld's
firs
t DC
ele
ctric
(ba
ttery
-ope
rate
d) m
otor
.T
his
inve
ntio
n w
as b
ased
on
anot
her
of F
arad
ay's
dis
cov-
erie
s. In
182
1, F
arad
ay le
arne
d th
at e
lect
ric c
urre
nt c
ould
crea
te m
echa
nica
l mot
ion
or a
type
of "
mov
ing
mag
net."
His
dev
ice
was
a w
ire (
elec
tric
coil)
whi
ch w
ould
rot
ate
arou
nd a
mag
net w
hen
curr
ent
was
app
lied.
How
ever
, unl
ike
Far
aday
's in
vent
ion,
Dav
enpo
rt's
mot
or u
tiliz
ed a
nel
ectr
omag
net i
n pl
ace
of a
natu
ral m
agne
t, in
crea
sing
the
mot
or's
pot
entia
l pow
er.
A m
otor
is s
impl
y tw
om
agne
ts w
orki
ng in
opp
osi-
tion.
The
sta
tiona
ry m
agne
t or
elec
trom
agne
t is
calle
d th
est
ator
, whi
le th
e ro
tatin
g el
ectr
omag
net i
s ca
lled
the
roto
ror
arm
atur
e. A
bas
ic e
lect
ric m
otor
con
sist
s of
only
four
mai
n pa
rts:
sta
tor,
rot
or/a
rmat
ure,
com
mut
ator
and
bru
shes
.
T h
ere
are
two
type
s of
mot
ors
thos
e th
at o
pera
te o
nD
irect
Cur
rent
(D
C)
and
thos
e th
at o
pera
te o
n A
ltern
atin
gC
urre
nt (
AC
). A
DC
mot
or w
orks
bec
ause
the
spin
ning
mag
net k
eeps
tryi
ng to
line
up
oppo
site
pol
es w
ith th
est
atio
nary
mag
nets
. With
eac
h ha
lf tu
rn, t
he s
plit
cont
acts
of th
e co
mm
utat
or fu
nctio
n au
tom
atic
ally
to c
hang
e th
epo
larit
y of
the
roto
r. (
Fig
. 21.
1)
Fig
. 20
Ear
ly D
.C. M
otor
1880
Edi
son
pate
nts
the
glas
s en
clos
ed fu
se.
3 8
3
NE
*111
1
Fig
. 21
Pol
arity
cha
nge
of r
otor
D.C
. ma`
or
AC
mot
ors
do n
ot h
ave
split
rin
g co
mm
utat
ors.
Thi
s is
beca
use
Alte
rnat
ing
Cur
rent
rev
erse
s th
e po
larit
y of
the
curr
ent a
utom
atic
ally
. Bec
ause
of t
his,
the
com
mut
ator
inan
AC
mot
or is
set
up
as s
epar
ate
rings
. (F
igur
e 21
.2)
Try
Exp
erim
ent 8
to fu
rthe
r ex
plor
e th
e in
vent
ion
of th
e D
.C.
Mot
or.
C-A
71P
LED
.C. M
OT
OR
Fig
. 21.
1
Spl
itrin
g co
mm
utat
or
Bru
sh
Pol
esco
nsta
nt
Sta
tor
(D.C
. Ele
ctro
mag
net)
Pol
esco
nsta
nt b
ut o
ppos
ite r
otor
pol
es Fig
. 21.
2'Act
ivity
MA
GN
ET
IC F
OR
CE
See
how
a m
otor
wor
ksus
ing
two
bar
mag
nets
. Firs
t,tr
y m
akin
g th
em r
epel
eac
hot
her,
then
attr
act e
ach
othe
r. W
hat y
ou a
re o
bser
v-in
g is
the
prin
cipl
e of
mag
-ne
tism
. Eac
h m
agne
t has
ano
rth
and
sout
h po
le, j
ust
like
the
eart
h. T
he li
ke p
oles
(N/N
, S/S
) of
the
mag
nets
repe
l eac
h ot
her,
just
as
the
oppo
site
pol
es (
SIN
) of
the
mag
nets
attr
act.
Tha
t's w
hya
mot
or w
orks
. The
pol
arity
of th
e st
ator
and
rot
or p
oles
are
in c
onst
ant o
ppos
ition
;pr
ovid
ing
the
forc
e th
attu
rns
the
roto
r. (
Fig
21)
A S
IMP
LE A
.C. M
OT
OR
A.C
. Ele
ctra
mag
net
Pol
es a
ltern
ate
oppo
site
to r
otor
Rot
or/
vf..a
rmat
ure
Bru
sh
\IIIIM
MIO
INtle
2
I II
D.0
pow
er s
ourc
e
Com
mut
ator
s
Bru
sh
1882
Firs
t DC
mun
icip
al p
ower
plan
t put
into
ope
ratio
n.
AL.
pow
er s
ourc
e
A 1883
Firs
t ele
ctric
str
eet r
ailro
ad w
as3
9st
arte
d in
the
U.S
. in
Bal
timor
e, M
d.19
SC
IEN
CE
FU
N W
ITH
ELE
CT
RIC
ITY
Prio
r to
187
3 al
lel
ectr
ic m
otor
s w
ere
batte
ry p
ower
ed.
Tha
t is
until
Bel
gian
scie
ntis
t Z'e
nobe
The
ophi
le G
ram
me
dem
onst
rate
d th
at a
mot
or c
ould
be
pow
ered
by
age
nera
tor.
Exp
erim
ent 8
BU
ILD
A P
C E
LEC
TR
IC M
OT
OR
Bui
ld th
e sa
me
type
of "
mov
ing
mag
net"
orig
inal
lydi
scov
ered
by
Far
aday
. You
may
als
o bu
ild o
nefr
om a
kit.
Thi
s in
clud
es m
otor
s th
at u
se a
n el
ectr
omag
netf
or
tile
stat
or r
athe
r th
an a
mag
net.
Sev
eral
goo
d ki
ts a
rcav
aila
ble
and
can
be o
btai
ned
from
a h
obby
sto
re, t
oyst
ore,
the
Boy
Sco
uts
ofA
mer
ica
Sup
ply
Cat
alog
or
by
,ca
lling
NA
SC
O a
t 1-8
00-5
58-9
595.
Y o
u w
ill n
eed:
15 fe
et o
f 22
gaug
e el
ectr
ic m
otor
wire
Tap
eT
hin
plas
tic o
r w
oode
n ro
d1
6-vo
lt la
nter
n ba
ttery
Blo
ck o
f woo
d4
nails
Bar
mag
net (
or e
lect
rom
agne
t)K
nife
Ham
mer
Bro
om h
andl
e
Usi
ng th
e co
pper
wire
,m
ake
a ne
at c
ircul
ar c
oil b
yw
indi
ng 3
0 tu
rns
of th
e w
irear
ound
a b
room
han
dle.
Rem
ove
the
coil
and
flatte
n its
win
ding
s, to
mak
e a
ring
shap
e w
ith p
roje
ctin
g w
ireen
ds. K
eep
the
coil
in s
hape
by b
indi
ng it
spa
ringl
y w
ithlit
tle p
iece
s of
stic
ky ta
pe.
Stic
k th
e co
il on
the
rod
as s
how
n. S
crap
e aw
ayin
sula
tion
from
the
ends
of t
he w
ires
proj
ectin
gfr
om
,th
e co
il. A
ttach
the
ends
of t
he b
are
wire
on
oppo
site
side
s of
the
rod,
usi
ng th
in b
ands
of t
ape.
The
exp
osed
wire
s ar
e ca
lled
com
mut
ator
con
tact
s (1
and
2) a
nd th
e
coil
is c
alle
d th
e ar
mat
ure.
Com
mut
ator
bare
d w
ire I
Tap
e
,
AR
MA
TU
RE
Tap
e
00,1
00T
ape
01'
Com
mut
ator
bare
d w
ire 2
Tap
e Cro
ssed
nai
ls
Bar
mag
net
Fig
. 24
OO
OO
OO
OO
OO
. "
20()
SC
IEN
CE
FU
N W
ITH
ELE
CT
RIC
ITY
1885
Elih
u T
hom
son
inve
nts
the
circ
uit b
reak
er.
1886
EC
hu T
hom
son
pate
nts
Ifit
elec
tric
al w
eldi
ng s
yste
m.
1886
Firs
t AC
mun
icip
al p
ower
plan
t put
into
ope
ratio
n.
Mou
nt th
e ro
d (w
ith it
s ar
mat
ure
and
com
mut
ator
inpl
ace)
bet
wee
n tw
o pa
irs o
f cro
ssed
nails
or
a bl
ock
of
woo
d. (
See
Fig
ure
24.)
Put
a s
tron
g ba
r m
agne
t jus
tun
der
the
arm
atur
e w
here
it w
ill n
ot o
bstr
uct t
he a
rma-
ture
as
it is
spu
n.
Mak
e tw
in le
ads
from
thin
wire
s an
d co
nnec
t the
mto
)a 6
-vol
t bat
tery
. Bar
e th
eir
othe
r en
ds fo
rab
out 2
inch
es to
mak
e br
ushe
s fo
r th
e m
otor
. Set
the
rod
with
com
mdt
ator
con
tact
s 1
and
2 on
a le
vel.
Tou
chth
e
cont
aCts
with
the
side
s of
the
brus
hes,
whi
ch y
ou h
old
vert
ical
ly. T
he m
otor
sho
uld
star
t by
itsel
fan
d ke
epsp
inni
ng. I
f not
, hav
e so
meo
ne g
ive
the
spin
dle
a tu
rn.w
hile
you
hol
d th
e br
ushe
s in
pla
ce a
gain
st th
e co
mm
u-ta
tor.
Wha
t Can
Go
Wro
ng?
Too
muc
h fr
ictio
n w
ith th
e cr
osse
d na
il be
arin
gsA
bad
ly-b
alan
ced
arm
atur
e co
ilS
hort
-circ
uitin
g of
cur
rent
bet
wee
n w
ires
1 an
d 2
if
they
touc
hP
oor
batte
ry c
onne
ctio
nsT
he m
agne
t pla
ced
too
far
away
from
the
arm
atur
e
Insu
latio
n no
t scr
aped
off
of c
omm
utat
or w
ires
The
re a
re m
any
kind
s of
mot
ors.
If y
ou c
ompl
eted
Exp
erim
ent 8
, you
mad
e a
liken
ess
of F
arad
ay's
exp
eri-
men
tal D
C m
otor
; sin
ce it
ope
rate
s on
dirc
ct c
urre
nt.
The
re a
re a
lso
mot
ors
whi
ch o
pera
te o
n A
C (
alte
rnat
ing
curr
ent)
and
are
use
d ar
ound
the
hom
e an
d in
bus
ines
ses.
A 1888
Oliv
er S
halle
nber
ger
inve
nts
elec
tric
met
er.
42
1888
Am
eric
an-b
orn
Nik
ola
Tel
sa c
onst
ruct
s fir
stA
C m
otor
to b
e po
wer
ed b
y a
gene
rato
r.
43
21S
CIE
NC
E F
UN
WIT
H E
LEC
TR
ICIT
Y
ELE
CT
RIC
LIG
HT
Pro
babl
y on
e of
the
mos
t sig
nific
ant e
lect
rical
inno
va-
tions
of t
he c
entu
ry c
ame
by w
ay o
f an
inve
ntor
nam
edT
hom
as E
diso
n. E
diso
n w
as a
ttem
ptin
g to
cre
ate
anin
expe
nsiv
e so
urce
of l
ight
usi
ng e
lect
ricity
from
a D
.C.
gene
rato
r. U
ntil
then
, lig
ht w
as p
rovi
ded
byca
ndle
s an
doi
l and
gas
lam
ps. A
ttem
pts
wer
e ev
en m
ade
to c
reat
e an
arc-
type
lam
p fr
om a
ref
lect
ed m
etal
spa
rk.
Edi
son
and
othe
r in
vent
ors
note
d th
at if
a c
oil s
tran
d of
wire
got
hot
from
too
muc
h el
ectr
ic c
urre
nt, i
t glo
wed
. The
pro
blem
;E
diso
n an
d ot
hers
face
d w
as th
at th
e m
ater
ials
wou
ld.
even
tual
ly b
reak
or
burn
up
from
the
heat
.(F
igur
e 25
)
4422 S
CIE
NC
E F
UN
WIT
H E
LEC
TR
ICIT
Y
Afte
r te
stin
g m
ore
than
6,0
00 m
ater
ials
,E
diso
n ga
vebi
rth
to th
e fir
st e
lect
ric li
ght o
n O
ctob
er 2
1, 1
879.
He
disc
over
ed th
at c
arbo
nize
d se
win
g th
read
mou
nted
insi
dea
glas
s bu
lb w
ould
glow
con
tinuo
usly
whe
n th
e ai
r w
asre
mov
ed fr
om th
e bu
lb a
nd c
urre
nt a
pplie
d. T
hela
mp
cont
inue
d to
bur
n fo
r ab
out 4
0 ho
urs.
In fa
ct, i
t was
only
afte
r E
diso
n in
crea
sed
the
volta
ge to
the
bulb
that
itbu
rned
out
. Try
exp
erim
ent 9
to fu
rthe
r ex
plor
eth
is
disc
over
y.
Fig
. 25
Com
paris
on o
f Edi
son'
s fir
st la
mp
with
a m
oder
n in
cand
esce
nt ty
pe.
Vac
uum
sea
l off
tip
Ter
min
als
Bas
e
Gla
ss b
ulb
Fila
men
t
Sup
port
Gla
ss b
utto
n
But
ton
supp
ort
Inne
r le
ads
Gla
ss s
eal
Exh
aust
tube
She
ll
Con
tact
1892
Firs
t ele
ctric
aut
omob
iles
wer
e pu
t on
the
mar
ket.
1895
Gug
lielm
o M
arco
ni in
vent
sth
e w
irele
ss r
adio
.
45
Exp
erim
ent 9
, LIG
HT
A C
OIL
ED
ST
RA
ND
OF
WIR
EE
xper
ienc
e th
e sa
me
chal
leng
e th
at E
diso
n fa
ced
in c
reat
ing
the
elec
tric
ligh
t.
You
will
nee
d:P
iece
of w
ood
6 in
ches
of 3
0-ga
uge
wire
2 th
umb
tack
sS
mal
l nai
l2
6-vo
lt la
nter
n ba
tterie
s4
feet
of 2
2-ga
uge
insu
late
d w
ire, s
ingl
e st
rand
Sec
ure
two
leng
ths
of b
ell w
ire w
ith th
umb
tack
s to
a pi
ece
of w
ood
as in
Fig
ure
26. O
btai
n a
6-in
ch le
ngth
of a
sin
gle
stra
nd o
f the
wire
use
d in
a c
omm
on p
ower
cord
. You
will
hav
e to
cut
apa
rt a
n ol
d po
wer
cor
d or
ask
for
6 in
ches
of "
zip"
cor
d fr
om th
e ha
rdw
are
stor
e.W
ind
the
stra
nd o
f wire
aro
und
a sm
all-d
iam
eter
nai
l to
prod
uce
a co
il of
wire
. Con
nect
the
free
end
s of
this
coil
to th
e be
ll w
ire a
s sh
own.
Now
con
nect
the
entir
e ci
rcui
t to
one
6-vo
lt ba
ttery
and
wat
ch w
hat h
appe
ns. T
he c
oil w
ill h
eat,
and
the
clos
e tu
rns
of h
igh-
resi
stan
ce w
ire p
rodu
ce e
noug
hhe
at to
glo
w. I
ncre
ase
the
volta
ge b
y w
iring
the
batte
r-ie
s as
sho
wn
Fig
ure
26.1
. Eve
ntua
lly th
is c
ircut
will
fail
beca
use
the
inte
nse
heat
will
wea
ken
the
wire
and
caus
e it
to b
reak
. BE
VE
RY
CA
RE
FU
L W
HE
N D
OIN
GT
HIS
EX
PE
RIM
EN
T. T
HE
HE
AT
PR
OD
UC
ED
IS Q
UIT
EH
IGH
AN
D C
AN
CA
US
E S
ER
IOU
S B
UR
NS
OR
EV
EN
CA
US
E P
AP
ER
TO
BU
RN
.
"Zip
" co
rd
Bel
l wire
Rem
ove
one
stra
nd o
f wire
Coi
led
stra
nd o
f wire
Fig
. 26
Illum
inat
ed w
ire c
oil
Fig
. 26.
1
1896
Tho
mas
Edi
son
appl
ies
for
pate
nton
the
fluor
esce
nt la
mp.
4 6
1899
Firs
t ad
for
G.E
. lig
ht b
ulbs
app
ears
in th
eS
atur
day
Eve
ning
Pos
ton
Feb
ruar
y 4
.
GO
ING
BE
YO
ND
Now
that
you
've
com
plet
ed th
is p
roje
ct,
thin
k ab
out g
oing
bey
ond
in th
e 4-
H E
lect
rical
Ene
rgy
Ser
ies.
Uni
t 2 e
xplo
res
toda
y's
appl
icat
ion
ofel
ectr
icity
in th
e ho
me
incl
udin
g w
iring
, lig
htin
gan
d sw
itche
s. U
nit 3
intr
oduc
es y
ou to
the
wor
ld o
f ele
ctro
nics
. You
may
also
wis
h to
take
Lear
ning
Abo
ut C
ompu
ters
or R
adio
Con
trol
led
Ve-
hicl
es a
s a
com
pani
on to
your
4-H
ele
ctric
al
proj
ects
.
4 7
23S
CIE
NC
E F
UN
WIT
H E
LEC
TR
ICIT
Y
'I P
LED
GE
MY
HE
AD
TO
CLE
AR
ER
TH
INK
ING
,
14Y
HE
AR
T T
OG
RE
AT
ER
LO
YA
LTY
,
MY
HA
ND
S T
O L
AR
GE
RS
ER
VIC
E A
IND
MY
HE
ALT
H T
O B
ET
TE
RLI
VIN
G, F
OR
MY
CLU
B, M
Y C
OM
MU
NIT
Y,
MY
CO
UN
TR
Y
AN
D M
Y W
OR
LD.
...7
soii,
0