| Demo |
Topic |
Short Name |
UMd |
Materials |
Long Description |
| 1
Collisions-04 Nuclear-03 |
intro
|
double ball bounce |
basketball tennis ball (well inflated) |
bounce tennis ball bounce basket ball place tennis ball over basketball and drop The tennis ball will bounce HIGH! (by varying the placement of the tennis ball on the basketball you can crudely aim the tennis ball) |
|
2 Pressure-02 |
intro
|
seat of nails |
seat of nails apple |
drop apple on seat. It will be impaled. let students feel nails (they are unblunted) place seat of nails on chair sit down slowly. Don't wear expensive pants. Jeans work best. Shorts can be slightly painful. |
|
3 Induction-06 |
intro
|
ringshooter |
ringshooter various rings |
shoot rings in the air |
|
4 Newton's 1st-01 |
inertia
|
coin drop in glass |
glass or beaker cardboard sheet coin |
place coin on cardboard sheet on glass ask class what will happen when the card is flicked flick card, coin will drop into glass |
|
5 Newton's 1st-02 |
inertia
|
weight and string pull |
c3-03 (similar) |
two lab stands separated by 18" supporting a
horizontal arm between them about 2' above the table tie a 12' cotton thread to the arm and a 0.5 kg mass to the bottom of the thread. Tie a second cotton thread to the bottom of the mass. The mass is now suspended from 12" cotton thread with 12" of cotton thread below. Have three of these for repeated tries. Nylon thread will not break. |
ask class which thread will break when I pull
on
the bottom thread. a) pull slowly. top thread will break b) jerk quickly. bottom thread will break |
6 Newton's 1st-03 |
inertia
|
small steel ball |
c3-01 |
demo with post, card, ball and flicker |
place ball on card on post pull back flicker let go |
7 Newton's 1st-04 |
inertia
|
hit prof with hammer |
c3-04
(similar) |
hammer (standard) two pieces lumber, each 4.5"x4.5"x12" (or equivalent) rubber padding large nail (10 or 12 penny) |
start nail into one piece of wood place padding on head, two pieces of wood on top of padding (hold lumber with your hands to make sure it stays in place) get student volunteer to pound the nail into the wood warnings: 1) try this with a friend first to make sure a) the padding is thick enough and b) the lumber has enough inertia, 2) do not choose the biggest guy in the class to do this, 3) make sure they miss your fingers (and theirs) |
8 Newton's 1st-06 |
inertia
|
walk and drop |
you something to drop |
walk at constant velocity ask class to predict where the weight will hit (in front, next to, behind you) drop weight |
|
8a Newton's 1st-07 |
inertia
|
walk and drop |
c2-28 |
you ball bucket |
place bucket on floor walk at constant v with ball ask class: where should you release the ball so it lands in the bucket? |
9 Newton's 1st-05 |
inertia
|
toilet paper pull |
full roll of TP almost empty roll of TP |
Put them on a toilet paper holder of some
kind
(eg: a horizontal metal rod) so they are free to
spin. Grab
a square of TP and give it a sharp jerk. The piece of
TP from the
full roll will
be ripped from the roll. The empty roll will
spin and the
rest
of the TP will land on the floor. Why? |
|
10 Newton's 1st-08 |
inertia
|
vertical ball shooter |
c2-25 |
PASCO cart with vertical ball shooter,
trigger,
and track (with bumper on the far end), bubble level. |
Show the class what you will do and how the
ball
shooter works. Ask class to predict where the ball will hit (in front, next to, behind the cart). cock the ball shooter and give the cart a push. (set this up before class to make sure the ball shooter is aimed properly and the ball lands in the shooter) |
11 Gravity-01 |
Gravity
|
Guinea and Feather |
c4-33 |
Guinea and Feather demo tube (clear plastic
tube
containing a nickel and a rather smashed cotton ball) (we
also have a
less
visible and narrower coin and feather tube) vacuum pump |
Ask class, which will hit the bottom of the
tube
first, the coin or the cotton ball. Pump the air out of the tube, invert it. The two objects should hit simultaneously. Note that there is some grease at one end of the tube. Do not start the drop from that end (since the cotton ball will stick). PRACTICE FIRST. |
12 Gravity-02 |
Gravity
|
tool and feather |
Apollo
movie |
show movie of wrench and feather dropped on
the
Moon |
|
13 Gravity-03 |
Gravity
|
drop stuff |
paper textbook |
drop paper, it falls slowly crumple paper, it drops faster drop text book, it drops even faster ask students which will fall faster, the book or the paper. place paper under book and drop students will complain! place paper over book and drop. They still fall at the same rate! |
|
14 Newton's 2nd-01 |
F=ma
|
force and acceleration |
c4-01 |
track, pasco cart, pulley, string, hanging
masses |
Demonstrate the F=ma. Level track. Place cart on track. Attach string to cart, over pulley, to mass hanger. Place mass on hanger. Release cart. It will accelerate. Increase the hanging mass (applied force), 'a' will increase. Increase the cart mass, 'a' will decrease. |
15 Newton's2nd-02 |
F=ma
|
kick boxes |
two identical appearing boxes, one with large
M
and one with small m |
kick both ask class which has more mass |
|
16 Newton's 2nd-03 |
3rd law
|
rolling chairs |
two rolling chairs (must roll well) one assistant hard floor |
sit in one chair a) asst pushes you, you go back b) you push asst, you go back c) have assistant sit in other both push, both go backwards I push, both go backwards you push, both go backwards |
|
17 Newton's 3rd-01 |
3rd law
|
balloon |
rubber balloon |
inflate let go |
|
18 Newton's 3rd-02 |
3rd law
|
rubber band |
rubber band |
pull back discuss forces involved let go |
|
18.2 Newton's 3rd-03 |
3rd law
|
tug of war |
15' of rope two volunteers (large and small) moving dolly or wheeled chair |
set up tug of war between volunteers quiz class which one exerts more force on the rope then make the larger volunteer sit or stand on the dolly or chair! this shows that the tug-of-war winner is the one who can exert more force on the floor |
|
19 Newton's 3rd-04 |
3rd law |
two spring scales |
c5-01 |
two large circular identical spring scales
suspended from a lab stand. The top one should be
right side up
and the bottom one should be upside down (so the top one
measures the
force exerted from below and the bottom one measures the
force exerted
from above) |
both scales read the same pull down on the bottom scale they still read the same |
20 Newton's 3rd-05 |
3rd law |
spring and pulley paradox |
c5-02 |
two lab stands, each with a pulley. two mass hangers, each with equal mass (1 kg) large circular spring scale string anchor the lab stands so they do not topple inwards |
1) use spring scale to show that the weight
of
the first mass + hanger is 10 N. 2) use spring scale to show that the weight of the second mass + hanger is 10 N. 2a) show that the weight of the mass + hanger is the same, even when you use the pulley. 3) attach string to first mass hanger, over the left pulley and attach to spring scale. Attach string to second mass hanger, over the right pulley, to other side of spring scale. The two masses are now pulling on the spring scale from two directions. DO NOT LET THE CLASS SEE THE SCALE YET. 4) ask the class to predict the reading on the scale. 5) show them! |
21 Newton's 3rd-06 |
3rd law vectors |
sailboat upwind |
c5-31 |
dynamics cart track Make block with 3 slots, at 0, 45 and 90 degrees. Make a solid "sail" that is about 8" square that fits neatly into the slots. fan or hair dryer |
Can the fan make the cart move 'upwind' place normal sail on cart and fan behind. Cart moves place 45 degree sail on cart and fan behind. Cart moves place fan perpendicular. cart moves place fan mostly perpendicular but slightly ahead. Cart still moves! |
22 Newton's 3rd-07 |
3rd law |
reaction cart |
c5-14 |
reaction cart with fire extinguisher crash helmet for dramatic effect |
sit on cart squeeze extinguisher handle hold on (be careful. this can attain high speed. PRACTICE FIRST) |
22a Newton's 2nd-03 |
vectors |
rope and weights |
15 foot rope 2 kg masses |
get two volunteers ask class if they can pull hard enough to make the rope straight Have them try Then add 2 kg and have them try again! |
|
23 Collisions-01 |
stopping |
egg and sheet |
3 eggs (raw) sheet 2 volunteers paper towel |
hold sheet with volunteer. Hold one end
of
sheet high and let the other end drape down and back up so
it looks
like
a J in cross section. Do not hold the sheet tight. Have the other volunteer throw the egg (hard) at the sheet. Be prepared to clean up after misses. |
|
24 Collisions-02 |
collisions |
happy/unhappy balls |
c7-16 |
happy and unhappy balls |
one bounces one doesn't |
25 Collisions-03 |
collisions |
happy/unhappy balls and block |
happy and unhappy balls, track with lab stand block to knock over |
set up the track and block carefully so that
when you roll the happy ball down the track, it knocks over
the block
but the
unhappy one won't. query the class which will knock over the block then do it |
|
26 Collisions-05 |
collisions |
air track collisions |
c7-01 c7-02 c7-03 c7-04 |
air track blower large cart small cart |
various collisions a) elastic (with bumpers) same mass, different mass, both moving, one moving b) inelastic (need to jigger this with screws and magnets) As always, PRACTICE FIRST. |
27 Energy Conservation-01 |
E con |
bowling ball pendulum |
c8-01 c8-02 |
bowling ball pendulum attached to eye in
ceiling backdrop (eg: table piled with empty boxes) |
sit in chair immediately in front of boxes
(head
against boxes), pull bowling ball to head, give it a small
push, get
out
of the way! Go oops! Redo without pushing the pendulum to show that your head is safe. Can also do this standing. The backdrop can then be a piece of plywood mounted on a ladder. |
28 Energy Conservation-02 |
E con |
billiard ball race |
c2-11 |
Aluminum billiard ball tracks, one straight,
one
dips. two billiard balls stick to push them equally with box or stopper for the far end |
roll ball on flat track start both balls with same v and stop them query class: which will win the race do it. make sure you give a large enough initial v to overcome the extra friction in the dip track. |
29 Rotation-01 |
Rotation |
bike wheel |
bicycle wheel with handle at hub |
use to demonstrate rotational position, v, a show that a quarter on the rim will slide off if v is large enough |
|
30 Rotation-02 |
Rot |
AC lights |
AC lights on a long cord |
plug in lights, darken room, swing in a
circle shows that x = r*omega so the larger the radius, the larger the arc covered |
|
31 Rotation-3 |
Rot |
rot stability |
parallel tracks (eg: two meter sticks with a
4"
separation) double cones a) two paper cups attached mouth to mouth b) two paper cups attached base to base |
Roll double cup down track. Show that
the
mouth-to-mouth cups roll stably. |
|
32 Rotation-04 |
Rot Inertia |
Rolling Race |
Large blue triangular wooden rolling tracks 2 blue rolling disks |
which will win? the disks with the weights
inside or the weights outside? |
|
33 Rotation-05 |
Rot Inertia |
Balancing sticks |
long stick with weight on one end |
easier to balance with weight up or weight
down? |
|
34 Rotation-06 |
Rot Inertia |
twisting sticks |
pairs of sticks, apparently identical in each pair, one has weights near center, the other has weigths near end |
twist back and forth. what's the difference? |
|
35 Rotation-07 |
Rot Inertia |
racing pendula |
two pendula, swinging from a horizontal bar
attached to a lab stand one pendulum has the bob near the top, the other near the bottom |
which pendulum will be faster? |
|
35.5 Rotation-08 |
Rot Inertia not made yet |
Baseball bat sweet spot (not made yet) |
d2-21 |
Baseball bat hanging from its
thick end small bell attached to thin (handle) end mallet (or baseball on stick) to hit bat with |
Strike bat with mallet (or
baseball) bell will ring except when struck at the sweet spot (NB: UMd demo not identical) |
36 Torque-01 |
torque |
torque |
wooden meter stick suspended in the middle points to hang weights from various weights string to hang some weights lower than others |
show a) equal weights at equal distances
balance b) unequal distances don't c) Mr = mR will balance d) hanging the weight lower makes no difference |
|
37 Center of Mass-01 |
CM |
thrown CM |
thrown CM demo (wood block with light at CM) |
darken room throw upwards light follows a nice parabola |
|
38 Center of Mass-02 |
CM |
irregular shape CM |
irregular shape CM demo lab stand to suspend it from string and plumb bob |
suspend CM demo from stand, hang plumb bob
from
same point. draw vertical line repeat for two more points lines intersect at CM |
|
39 Center of Mass-03 |
CM |
fork and glass |
glass, 2 forks, coin (quarter works best) (identical forks work best) |
balance two forks on coin on glass practice first! Put forks tines together and parallel insert quarter with one edge between two tines of both forks balance other edge of quarter on rim of glass place on overhead projector for viewing |
|
40 Center of Mass-04 |
CM |
touch toes |
touch your toes with your heels against the
wall |
try it! |
|
41 Center of Mass-05 |
CM |
kick CM |
CM block with markers in it long sheet of white paper |
place paper on ground place CM block on paper kick it so it goes forward and spins the central marker will go straight as the side markers swirl around it. |
|
42 Center of Mass-06 |
CM |
Ernest CM |
Ernest the balancing bear string |
||
43 Center of Mass-07 |
CM |
L-shaped CM |
Two identical L-shaped objects |
Find the CM show that they balance with the long side down |
|
44 Center of Mass-08 |
CM |
boy/girl CM |
two volunteers |
Have each one kneel with elbows to
knees.
Place a small object at the fingertips. Put hands
behind
back.
Try to knock over the object with your nose. Boys
mostly can't do
it. Girls mostly can. |
|
45 Centripetal Force-01 |
centripetal force |
loop-the-loop |
D1-53 |
loop-the-loop track ball |
When the ball has enough speed (ie: when it
is
released from high enough up), it will loop the loop.
At lower
speeds it will fall off. |
46 Centripetal Force-02 |
centripetal force |
rotating bucket |
d1-41 |
bucket of water |
swing bucket in big circle water stays in it |
47 Centripetal Force-03 |
centripetal force |
cup on rotating tray |
tray suspended by string cup of water (not glass!) |
place cup on tray swing in big circle practice first |
|
48 Centripetal Force-04 |
centripetal force |
coin on bike wheel |
coin bike wheel |
place coin on wheel near rim spin wheel coin falls off |
|
49 Angular Momentum-01 |
ang mom |
rotating stool and weights |
d3-03 |
rotating stool weights |
student sits on stool (weight centered!) holds weights close to chest spin stool (not too fast, not too slow) students brings weights out and in |
50 Angular Momentum-02 |
ang mom |
rotating stool and wheel |
d3-05 |
rotating stool weighted bike wheel with handles |
student sits on stool (weight centered!) hold wheel in vertical plane spin wheel tilt wheel one way, then the other |
51 Angular Momentum-03 |
ang mom |
mystery suitcase |
mystery suitcase motor |
remove protective slat from the bottom of the
suitcase start the motor spinning (it prefers to spin one way rather than the other, you might need to give it a push to start it spinning) place the suitcase carefully on the motor so it makes the wheel inside spin rapidly put the protective slat back on ask people to pick up the suitcase, walk with it, turn around, and return. |
|
52 Angular Momentum-04 |
ang mom |
gyro wheel |
weighted bike wheel with handles and an
attached
rope |
spin wheel suspend from rope watch precession |
|
53 Gravity-04 |
gravity |
weightlessness |
bucket styrofoam cups water |
fill cup with water poke hole in side near bottom with pen ask class: will water flow change when dropped? drop into bucket |
|
54 Projectile-01 |
trajectory |
ball dropped and shot |
c2-21 |
gizmo to drop and shoot two balls
simultaneously |
ask class to predict which ball will hit the
ground first do the demo |
55 Projectile-02 |
trajectory |
monkey shoot |
c2-22 |
gizmo to make target drop simultaneous with
ball
launching |
aim the launcher at the target select a launch speed leave enough room for the target to fall launch ball w/o letting target fall (it misses) ask class to predict whether ball will hit target launch! |
| 56 Electrostatics-01 |
electrostatics |
electrostatics |
j1-01
j1-05 |
glass, plastic and rubber rods fur, wool, and silk cloths display (projection) electroscope balloons (small) suspended metal-painted ping pong balls scotch tape |
Place electroscope on overhead projector. rub balloon on me or on fur. make it stick to me or wall. make hair stand up. touch to scope and see deflection rub fur on rubber rod, place rod on scope, see deflection rub silk on glass rod, place rod on scope, see deflection cancelled. do it again and see deflection. test this first! Place suspended PP ball on overhead projector (low enough to focus on it). rub fur on rubber rod. bring rod near suspended pp ball. It attracts and then repels (after touching). rip scotch tape from roll, touch to scope (also works w/plastic wrap) |
57 Electrostatics-02 |
electrostatics |
charged attracts neutrals |
glass, plastic and rubber rods fur, wool, and silk cloths 4' long wooden 2x4 beam watch glass |
balance beam on watch glass start beam normal to the audience (so the deflection is most obvious) charge rod (fur and rubber works best) hold near end of beam. watch it rotate |
|
57a Electrostatics-03 |
electrostatics |
charged attracts neutrals |
small piece of fur, pen, plastic knife and spoon rubber band |
Beforehand: wrap fur around
pen,
secure with rubber band, place in pocket (so the pen
is easily
removable) Place spoon overhead, balance knife on spoon Pull pen from pocket (rubbing it against the fur), hold near knife, make it rotate. Explain the trick! |
|
58 Electrostatics-04 |
electrostatics |
induction |
j1-12 |
glass, plastic and rubber rods fur, wool, and silk cloths projection electroscope ground wire |
charge rod, hold it near the electroscope
plate,
scope needle deflects ground the electroscope frame, needle undeflects move rod away, needle deflects, scope is charged by induction! |
59 Electrostatics-05 |
electrostatics |
van de Graaff |
j1-26 |
van de graaff generator plastic stool whirly-gig pie plates rice krispies in plastic cup (+broom) second dome (groundable to VDG ground) for throwing sparks to lightning rod (sharp rod attached to VDG ground) small (but not compact) fluorescent bulb |
bring grounded dome near vdg. throw big
sparks (more impressive with room lights off) next bring a grounded lightning rod near the dome (no more sparks!) place stack of pie plates on vdg dome. watch them fly off one by one place a cup of rice krispies on the vdg dome and watch them fountain! (bring a broom to clean up) (discuss electric field here) place whirlygig on vdg and watch it whirl hold bulb (near the end but not at it) with the other end pointing toward the vdg. it lights up. If it is held tangent to the vdg, it won't light. Why not? |
59a Electrostatics-06 |
electrostatics |
electric dipole / VDG |
|
van de graaff generator two metal balls on ends of wooden dowel (dipole) suspended by thread from a plastic rod short metal conductor labels for each ball |
Hold dipole pointing toward the VDG with the
conductor connecting the two balls While it is still pointing (and the VDG is on) remove the conductor The dipole is now charged by induction Walk around the VDG. One end of the dipole will always rotate to point toward the VDG. This demonstrates a) charging by induction, b) the torque on a dipole in an E field and c) the direction of the E field around the VDG |
60 Electrostatics-07 |
electrostatics |
hair raising |
j1-24 |
vdg plastic stool (or styrofoam block) victim |
get volunteer to stand on plastic stool (or
styrofoam block) place hands firmly on vdg turn it on and wait for the hair to stand up turn off vdg and ground it before letting volunteer let go |
61 Electrostatics-08 |
electrostatics |
induction |
glass, plastic and rubber rods fur, wool, and silk cloths two PASCO conductive balls on posts projection electroscope |
place two balls touching charge rod bring rod near one ball separate balls touch to electroscope to show that they are charged |
|
62 Electrostatics-09 |
electrostatics |
bouncing ball |
j1-27 |
vdg extra grounded dome metal painted or foil-wrapped pingpong ball suspended by two threads (for lateral stability) from a lab stand arm |
place conductive ping-pong ball between vdg
and
grounded dome turn on vdg watch ping-pong game! |
63 Circuits-01 |
current |
light the bulb |
lots of light bulbs, batteries, and wire (3-4" insulated wire with the ends stripped) |
distribute to the class ask them to light the bulb warn them that if the wire gets hot, they are doing something wrong! |
|
64 Circuits-02 |
current |
car battery and bulbs |
k6-03 |
car battery with tall terminals 3 light bulbs in bases with wires w/clip leads |
show complete circuit light one bulb show series and parallel circuits show bird on power lines |
65 Circuits-04 |
battery |
fruit battery |
fruit battery apple |
connect leads to fruit clock now works |
|
66 Circuits-03 |
current |
circuit boards |
k6-11 |
five premade circuit boards using D batteries
and small bulbs 1) series vs parallel 2) short circuit 3) 5 bulb conundrum 4) and 5) circuit conundrums (see UMd K6-11) |
show boards challenge class to predict results 1) which is brighter, 1 parallel bulbs or 2 series bulbs 2) what happens to the bulbs when the switch is closed (and shorts bulb B) 3) rank the 5 bulbs in order of brightness |
67 Magnetism-01
|
magnetism |
magnets |
j5-04 |
various magnets stuff to pick up (Fe, Al, plastic, wood, balloon) |
see what the magnets pick up charge the balloon, show it sticks to you, show the magnet does not pick it up. |
68 Magnetism-02 |
magnetism |
rotating magnet |
magnet on rotating stand another magnet |
show attraction and repulsion |
|
69 Magnetism-03 |
magnetism |
display compass |
compass needle in clear plastic case for
overhead
projection Note: fill compass case with water for damping |
show it points North affected by other magnets |
|
70 Magnetism-04 |
magnetism |
magnetic field (A) |
j5-01 |
bar magnet plastic tray iron filings |
place magnet under tray on overhead sprinkle filings gently tap to realign |
71 Magnetism-05 |
magnetism |
mag field (B) |
bar magnet plastic tray with internal iron filings in viscous fluid |
shake tray to redistribute filings place magnet underneath wait |
|
72 Magnetism-07 |
magnetism |
3D B field |
j5-03 |
bar magnet 3d B field visualizaer |
too small for large classes |
73 Magnetism-06 |
magnetism |
B field (C) |
j5-07 |
bar magnet array of small compass needles in plastic plate |
place bar on plate on overhead projector |
74 Magnetism-08 |
magnetism |
B field around wires |
j5-11 12 13 |
wire, loop and solenoid configurations
on
plastic trays power supply iron filings |
connect configuration to power supply run a LOT of current sprinkle filings |
74a Magnetism-09 |
magnetism |
B field around wires |
compass, wire and power
supply |
wrap the wire around the
compass 2 or 3 times connect the wire to the power supply see the compass needle deflect |
|
75 Magnetism-10 |
magnetism |
jumping wires |
k1-03 |
jumping wire setup power supply (perhaps we should reconfigure our demo to look like UMd's w/ hanging wire and horizontal forces) |
connect power supply to jumping wire setup turn supply (high current) operate knife switch (NOT SAFE!!!) |
76 Magnetism-11 |
magnetism |
small jumping wires |
k1-04 |
C-magnet wire 6 volt battery |
place C magnet with gap horizontal suspend loop in gap and connect wire to battery see deflection reverse B or I |
77 Magnetism-12 |
magnetism |
deflect e beam |
k1-11 |
deflect e beam with current in wire see UMd set up we don't do this one yet |
|
78 Magnetism-13 |
magnetism |
deflect e beam |
k1-12 |
electron beam tube tesla coil magnets |
either a) connect tesla coil to e-beam tube
or
b)
hold portable tesla coil near end of tube show e-beam on phosporescent screen hold magnet near tube to show deflection (and to show it reverses when the field reverses) |
79 (same as #74a) Magnetism-09 |
magnetism |
current and compass |
display compass power supply long wire |
place compass on overhead loop wire around compasss (2-3 loops) attach to power supply quiz class: how will compass deflect? turn it on! |
|
80 Magnetism-14 |
magnetism |
build an electromagnet |
iron nails (10 or 12) 20-24 guage insulated wire (3 feet long) sandpaper battery paperclips (one set per 2-3 students) |
have them build an electromagnet. |
|
81 Induction-01 |
magnetism |
DC motor |
DC motor power supply |
connect it up it spins! be careful to use as little current as possible |
|
82 Induction-02 |
induction |
coil, wire, galvanometer |
k2-01 (sort of) |
large coil several bar magnets wire to connect coil to galvanometer display galvanometer |
put display galvanometer on overhead wire it to the coil push magnet in and out |
82a Induction-03 |
induction not made yet |
coil w/LEDs, magnet |
k2-29 |
coil with two LEDs to show current direction magnet |
push magnet through coil, show direction of
current |
83 Induction-04 |
induction |
Large Lenz's tube |
k2-42 |
Large Lenz's tube two identical weights, one magnetic, one not |
get student to help. show that both weights are identical get student to drop one through (try to get her to choose the nonmagnetic one first) then have her drop the magnet ham it up while you wait for it to emerge make sure you show that the tube itself is nonmagnetic. query class what the difference is. |
84 (Not included) |
induction |
small Lenz's tube |
small Lenz's tube |
see above. Works better in lab than in
lecture. |
|
85 Induction-05 |
induction |
Lenz's pendulum (large) |
k2-44 |
lucite pendulum stand with aluminum disk as
pendulum
bob Large C magnet |
remove magnet, show pendulum swings freely place magnet, pull pendulum back and let go. |
85a (Not included) |
induction |
Lenz's pendulum (small) |
PASCO pendulum set (includes solid and
slotted
pendulum
bobs) |
good for lab |
|
86 Induction-06 |
induction |
ring shooter |
ring shooter and rings (solid Al, slotted Al,
plastic,
iron) |
Make the ring hover by placing it at the top
of
the iron core. Ask the class how much electromagnetic force
holds it
there
(assuming it weighs 1 N). Then shoot Al ring high in the air. How much EM force was exerted on that ring? Ask class what will happen with the slotted ring? Then ask about the plastic ring. Alternatively, put the slotted ring on, push the button, act like it's really hard to hold down (especially for a wimpy physics teacher). Ask for a strong volunteer to see how much force is required. Switch rings to the solid one. See how long the strong man holds it down. It gets HOT! |
|
87/81 Induction-07 |
induction |
motor/generator |
electric motor display galvanometer power supply (can do this either AC or DC) |
connect motor to power supply watch it spin connect motor to galvanometer, make it spin, generate current |
|
88 Induction-08 |
induction not made yet |
single wire induction |
k2-02 |
wire, galvanometer, C magnet (strong) |
more single loop of wire through magnet,
induce
current |
89 Induction-09 |
induction |
hand crank generator |
hand crank generator with light bulb |
crank generator, light bulb (in lab, you can have them crank it with and without the load to see that it is harder to crank when the bulb is connected) |
|
90 Induction-10 |
induction |
pistol-type generators |
two pistol-type generators light bulb (or other accessory) |
attach to bulb. crank one, light bulb attach to each other. crank one, other turns. One is motor, other is generator. |
|
91 Induction-11 |
induction |
ring shooter with coil and bulb |
k2-22 |
ring shooter coil and bulb |
push button, bulb lights light is dimmer when held higher up |
92 Induction-12 |
induction |
two coil 'radio' |
k2-24 (similar) k2-25 |
two coils metal core display galvanometer switch DC power supply |
Connect one coil to the galvanometer. Connect the other coil to the DC supply and the switch. Place the coils face to face without the core. Tap the switch showing the deflection of the meter. Redo with iron core lying through both coils. |
93 Induction-13 |
induction |
transformer |
PASCO transformer and coils set variac AC display voltmeter Can also do this with 1 and 2-loop coils made from regular wire. |
Attach the two coils to the iron core Attach
the
primary coil to the variac (don't use too much voltage) Attach the secondary to the AC voltmeter Compare the display voltages with those expected. Vary the number of turns in the secondary. |
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