Lecture Master List


Spinning Cylinder


Ping pong ball nuclear reaction: 2 or 3 balls per person in the room....hit throw

Coin Flip Radioactive decay model, needs 200+ people

Balloon model of solid, liquid, gas.



Frictionless airpuck human (fire extinguisher)

frictionless airpuck, CD with balloon

air bubble in tube

candle in a jar in freefall

switched stopwatch

drop a slinky what does the bottom do?

drop a slinky it expands like an astronaut's back

Ball bounce recording

falling frame balloon burst (Tien)

strings and weights on pie pan (A)

freefall bottle

dart gun and washer

distance versus time (run bike drive) )(A)

rolling acceleration (A)

Human bowling ball collision pendulum

Lunar walk

orbiting coin inside balloon (2 coins mate) pop - radioactive decay

tennis ball on basketball launch (superball)

raquet ball cut bend launch (hopper popper)

Force on climbing rope with scale

drop basket type coffee filters (fluids)

Falling stick (1 end on floor other end a > g)

Inclined plane with a car jack

falling 2L bottle with holes

whirl a bucket of water overhead

spinning cylinder



collapsing can

water pressure collapse

Soy sauce Cartesian divers

floating aluminum coins Crystal structure (A)

falling basket coffee filters

center of pressure of plane

soap convection in milk (A)

Bernoulli blower

Bernoulli bottle with tygon u-tube manometer (A)

Flubber recipe (A)

Float a potato in salt water under fresh water

oil will form a ball floating in water under isopropanol

entrainment blow a toilet paper roll with a blower

Balloon in a 2 Liter bottle with hole

fill it with water

battling balloons

flow vis

visual convection tray of flow vis over hand

Clear plastic case of CO2, butane lighter burns high above top of CO2

mist poured from beaker of dry ice and water floats on the surface of CO2

like a cloud layer

float bits of dry ice on a water surface, comet like

Hole in a bubble

make an airplane from a styrofoam plate



Whirly playing

bag whirly, blower

big whirly

Aluminum rod

long slinky

short slinky on fish line

short slinky spun from top, hung vertically

bicycle tuning fork (A)

phone cord pulses, resonance

mug of foam

Luisa's halftone sound model

harmonic singing

lightly hold a balloon to feel sound (in sound column)

straw oboe, sound vs length

Ken's straw music

string over hands over ears (pluck it, stroke it)



sound meters

binaural stethoscope sound intensity comparator

pipes-of-pan (S)

Breathe Sulfur Hexaflouride

Breathe Helium

Bang two 5 L plastic water containers together then hold the open ends next to your ears.



Flying tinsel

flying charged bubbles

electroscope (A)

charged tapes (A)

electrophorus (A)

balloon zap (A)

A battery dissection (A)

Amplifiers (A)



magnetism, AC with pick-up coil

disposable camera electronics (A)

High voltage (A) 9v battery pile


make a speaker

sound transmitted by light waves

listening to IR transmitters

neon tubes



Magnetic accelerator from Michel Junge (Newton's balls)

magnet collision on pencil, use multiples.

Shawn's levitation magnet over copper slab

Repel Grapes

Digital Audio tape (A)

Peirson Oscillators (A) Big or small on overhead

magnets on a pencil (A)

magnet collisions on a pencil (A)

magnets round the rim collisions (A)

magnets round the rim symmetry

define a north pole (multicultural) (Tien) (A)

simple poles (likes repel) (A)

magnetic poles advanced broken magnets, magnets side by side (A)

magnetic balancing act opposed on finger tip (A)

magnetic shielding (Tien) use cover of Klutz book

magnetism force vs distance (A) digital scale

earth sphere with magnet and magnaprobe (A)

projection magnetic dip (A)

magnetic model of electric current (A)

floating magnets (film can) (A) Garden of Magnets

air table magnets

Barkhausen effect, pick-up coil, cow magnet, radio shack amplifier

eddy currents open channel

magnetic levitation over spinning disk

Tien's Revolution (Tien)

Tien's film can iron filing magnetization model (Tien)

Magnetic field viewer paper

Nd attracts paper money

Canadian coins are magnetic (K)

recent English coins are magnetic

bashful coins (K)

Magnetic cannon (K)

magnet stack shot out of donut magnets (K)

guided magnetic roller roll Nd along aluminum channel

silent collisions (K)

magnetic pendulum strange attractor (K) On book cover

magnetic tug of war (A)

magnets 1 vs 3 (A)

Magnet rings even and odd magnets (A)

Suspense explainer (A)

Extract iron from cereal

magnetic orbiter, Nd slides on rotating inclined Al disk

Curie point coins

Magnetizing iron (hold a paperclip on a fork) ( K Explorabook)

the birth of a paperclip (K)

magnetic fluid from burned steel wool or magnaflux powder (Eric)

Paper clips in a bottle pulled up by magnet under lid

filings from VCR tape

magnetic feedback and frequency shift.

pierson oscilator



image walk (A)

antigravity mirror (A)

plastic on table (A)

finding images with foamcore straws and tripod (A)

eye chart

Image made by a cylindrical mirror (A)

image in ulexite

image in a hologram

light comparator (A) wax, plastic, grease spot

solar brightness vs 200 W bulb (A)

Camera dissection (A)

camera strobe and sound trigger

Fluorescent vs incandescent with comparator

minimag activities (A)


multi-shadow with holder and anti hole

dim maglite in a blindspot

diffraction naked eye, 3 x 5 card


candle diffraction

bright source

handmade minimag


dim minimag and retina

inverse square perf board

shadow through a frosted bulb

fresnel lens (A)

find the image

overlap lenses

image relay

jigsaw puzzle

make an image on a mirror with a fresnel

pupil mirror bug-box

rainbow dust (A)

soap film on a film can (A)

spectra diffraction grating


tidy bowl


slit under anti-slit


fraunhoffer lines

tapetum activity

U-V detector cards

bend a beam of light laser through water over clear karo


Bubble color (A)

Light island

polarization puzzle (squares with polarizer along the diagonal

Laser through a light bulb (x-ray shadow)


Visual perception

pinhole in film can (A)

1 pinhole vs 3 pinholes in filmcans

Gray Step (A)

Laser Speckle (A) (laser into frosted bulb)

Master eye (A)

Blacker than black (A)

how many moons in the bowl of the big dipper

moon illusion

after image size illusion

person vs distance size illusion

Hewitt's 2 eye vs 1 eye view hands at full distance 1/2 distance

Benham's disk on overhead (Centered top)

spiral on overhead




photo frame ripple tank

string thing (Don)

phone cord waves

giant slinky waves



group velocity make overheads with dark bands, and enlarged 10%

move them together or one faster, note group velocity



thermal postcards

solar power vs 200 W bulb (A)

give and take, black pens and overhead (S)

elastic model

conduction, propagation of heat and warmth with depth slides

convection, lamp, hands (A)

radiation, globe and sunlight (A)

evaporation (A)

seasons flat or wrapped around cylinder

Cloud in a bottle use a bike pump and isopropyl

match in water provides soot seeds and ion seeds too

Liquid nitrogen

balloons in a dewar

break a penny

freeze flowers in a dewar

break a frozen hot dog

hot dog in a playtex glove (break it )

make liquid oxygen and pull onto a magnet


Modern Physics

Radioactive Decay - audience coin flip and clap

RGB LED's (true green and bright blue)

Radioactive decay model (phosphorescent paint brightness)



Spin a Koosh (A)

Tide model (A) (E)

Magnet stack model of earth atmosphere

map projection (A)

timing earth rotation (A)

sidereal day

solar day

self-centered globe light distribution and temperatures by hand

contour lines

sea floor spreading model with magnetic tape strips

minimag and thermal postcard model of Hawaiian islands



Projection diffraction grating

fraunhoffer lines with holographic diffraction grating and thin distant slit,

expanding Universe overhead (star field and star field enlarged 10%



Circumference vs height of glass (A) (E)

toilet paper tube height vs circumference (E)

8.5 x 11 paper cylinder volumes (E)

deflection of beams

deflection of floor or wall (mirror laser beam)

milli can coins in film cans

Take it from the top (A) with cassette boxes

mobius collisions



Camera dissection

Descriptions of the activities


Whirly Playing

Whiled Music, the Science of corrugated tube sounds.

I play music on an assortment of different size corrugated plastic tubes by whirling them around in circles. Between playing the tubes I tell stories and do activities which show the science behind the singing tubes. I can play tubes up to 12 feet long and 6 inches in diameter, if the stage is large enough. I also play the bag whirly, a corrugated tube with an inflated garbage bag on one end &emdash; it is played like a bagpipe by squeezing the bag under one arm.


Frictionless Airpuck

I ride a disk which slides without friction on a cushion of air. A battery operated leaf blower blows air into the disk. I hold a Carbon Dioxide Fire Extinguisher and use its blast as a rocket propulsion system.


Breathe Sulfur Hexaflouride, Breathe Helium

I breath helium from a balloon the frequency of my voice more than doubles.

Then I breathe sulfur hexaflouride from a balloon, which by the way behaves like a lead balloon, and the frequency of my voice is lowered to less than one-half.


Air bubble in tube

I have a 1 meter long, 2 inch diameter clear plastic tube with water and a 2" diameter air bubble inside it. The bubble floats to the top of the tube. Let the bubble rise to the middle of the tube and then drop the tube and the bubble stops rising. The air in the bubble and the water in the tube fall together in free fall. Let the bubble rise to the middle of the tube then throw the tube into the air keeping it vertical and the bubble does not rise even when the tube is going up &emdash; the tube is in freefall even when it is going up. Hold the tube horizontal extending in front of you then spin around and the bubble comes toward the center of the circle of your spin.


Candle in a jar in freefall

Place a lit candle in a jar. Drop the jar. The candle goes out quickly. In freefall the oxygen depleted gas around the candle is not removed by convection.


Human bowling ball collision pendulum

While standing on top of a ladder, and belayed from above. Pull a bowling ball to your chin and release it. The ball will swing away and return but due to conservation of energy not hit you. The citing the need to test the symmetry of this experiment. Fix the bowling ball in place and swing away from it and back on the belay rope. Then, as a super collider the bowling ball and I swing away and back together at the same time.


Force on climbing belay with a scale

A climber hangs from a scale capable of reading 300 pounds. He holds both ends of a rope from the scale. The scale reads 150 pounds. The climber hands one end of the rope to another person to belay him and the scale reads 300 pounds.


Inclined plane with car jack

I stand on an inclined plane as another person jacks up the end of the plane with a car jack. When the angle gets steep enough my shoes slide down the plane. The tangent of the angle of the plane from horizontal tells me the friction coefficient of my shoes.


Whirl a bucket of water overhead

I have a water bucket and whirl it in a vertical circle over my head. The water stays inside the bucket. Then I put the bucket down and pick up another bucket full of glitter. When I stop the bucket over my head I get a bath of glitter.


Spinning cylinder (Not for large audiences.)

A piece of PVC pipe is spun and rotated at the same time. If it is marked at on end it produces patterns of marks. A tube cut three diameters long produces a triangle of marks. Spin the tube from the other end and the marks vanish.


Collapse the can

Small version:

Boil a small amount of water in an empty one gallon can. Take the can off the heat and immediately close it, it must be airtight. As the can cools it emits popping noises and eventually suffers a sudden collapse as the water vapor inside the can condenses leaving a partial vacuum in the can.

Large version

I can also collapse a 55 gallon drum. Add 2 liters of water. Boil it for 5 minutes. Turn off the heat, and then seal the can. It will collapse explosively.

Smallest version

You can boil water in an aluminum soda can, then invert the can in cold water and it will explosively collapse.


Floating aluminum coins (for large audiences on an overhead.)

I float aluminum coins in a tray of water. The coins are denser than water but are suspended by surface tension. Two nearby coins seems to attract each other moving together to form a coin dimer. Many identical coins come together to form a hexagonal closest packed structure.


Falling basket coffee filters

Basket type coffee filters fall stably and slowly.

Race a stack of 2 filters against one. Measure the height from which the two must be released in order to arrive at the ground at the same time as the single one. The double mass filter must be released from a height of 1.4 times the single one, i.e. the square root of 2 higher. This is because the air resistance is proportional to the square of the speed of fall of the filter. A quadruple mass filter must be dropped from twice the height of a single, while 9 nested filters must be dropped from three times the height of a single to reach the ground at the same time.


comet model

Float small bits of dry ice on the surface of a tank of water with a dark bottom. The bits of dry ice skitter about leaving a spinning trail of mist behind like the tail of a comet.


Hole in a bubble (small group demo)

Make a large bubble. Tie a loop out of string, leave a tail of string. Wet the string in bubble solution. Place the string on the bubble, keep hold of the tail. Puncture the bubble within the string and the surface tension of the bubble will draw the string out into a circle. The hole can then be moved around through the bubble film.


Ringing Aluminum Rod

I have a 1.5 meter long solid aluminum rod 1.5 cm in diameter. By striking this rod on the end while I hold it in the center I can make it resonate at its fundamental frequency. It rings for a very long time, for over a minute. Grab the rod at the end and it stops ringing, grab it near the middle and it doesn't stop ringing. How fast it stops ringing tells you how much it is moving at that point. The faster the sound dies away the more it is moving. So you can map the vibrational motion of the rod with your fingers. Hold the rod 1/4 of the way from one end and it will also ring for a long time, or 1/6 or 1/8. Map out the pattern of motion of these harmonics. There are also sounds due to bending of the rod. Strike the rod sideways at the end and excite the fundamental mode of bending which has a lower frequency.



Hold a slinky by one end and allow it to hang vertically. Drop the slinky and observe what happens to the bottom. (It remains at rest initially) The top meanwhile accelerates down with an acceleration greater than g.


Compress a slinky, then drop it. It will expand just like the spine of an astronaut.



talc in blanket for egg throw. poof white.

pop can to indicate slinky motion. pulses add to double motion.


antinode jumping

red hose full of water, wrap with retroreflector tape.











Scientific Explorations with Paul Doherty

© 2004

25 May 2004