Mechanics

Measurement

Basic Units

M-a1a

Meter Standard

A replica of the platinum-iridium bar in Paris that was the international standard for length before 1960.

Coordinate Systems

M-a3a

3-D XYZ axes

A simple 3-D XYZ Coordinate System

Vectors

M-a4a

Magnetic Blackboard Vectors

A set of magnet-backed vectors of lengths 3, 4, and 5 used to show vector addition on the blackboard.

M-a4b

Vector Addition Simulation

A 2-D and 3-D vector simulation: http://www.phy.ntnu.edu.tw/java/vector/vector.html

M-a4c

PhET Vector Addition Simulation

Colorado PhET 2-D vector simulation: http://www.colorado.edu/physics/phet/simulations/vectormath/vectorMath.swf

Scaling

M-a6a

Powers of Ten

"Powers of Ten" is a 9 minute film spanning scales from the edge of the universe to the sub-atomic

Motion in One Dimension

Velocity

M-c1a

Addition of Velocities--Tank and Sheet

A battery powered tank runs at constant speed on a moving paper to show how velocities add and subtract.

M-c1b

Linear Air Track: Position vs. Time

A glider travels down the 5 m air track while evenly spaced photogates record the elapsed time. One can then plot the position versus time for the glider on an overhead. The track may be inclined for uniformly accelerated motion.

Uniform Acceleration

M-c2a

Dime and Feather Tube

A penny and a feather fall freely inside a glass cylinder that can be evacuated.

M-c2c

Basketball and Tennis Ball drop

Basket and Tennis balls are dropped simultaneously from the same height.

M-c2b

Inclined Air Track

Prop up one end on an air track and use photogates to time the glider's voyage.

Measuring g

M-c3b

Timed Free Fall -- Classroom

A metal ball is dropped from 0.5m and then from 2m; a precise digital timer records the time of flight for each fall.

M-c3a

Timed Free Fall -- Lecture Hall

A metal ball is dropped from 1m and then from 4m into a catch bucket; a precise digital timer records the time of flight for each fall. [May conflict with Shoot-the-Monkey or Timed Free Fall.]

Position, Velocity, Acceleration

M-c4a

Motion Detector and Student

A student walks back and forth in front of an ultrasonic motion detector, and a real-time graph of her displacement (and/or veloctiy and/or acceleration) versus time is projected on the screen. [Currently out of commission.]

Motion in Two Dimensions

Displacement in Two Dimensions

M-d1a

Mounted Rotating 2D figure

An asymmetrical slab that can be mounted and rotated.

M-d1f

Balls on Rotating Disk

A disc with two balls mounted at different radii rotates at varying speeds. A third ball may be placed in the center if disk is horizontally mounted. Both orbital and spin rotations may be seen.

Velocity, Position, and Acceleration

M-d1e

High road low road

Two balls race, one down a slight incline and the other down an identical incline containing a valley.

Motion of the Center of Mass

M-d4b

Throwing Foam Slab

A slab of foam has its center of mass marked with a black dot; this dot follows a parabolic path when the slab is thrown.

M-d4c

Pendulum Air Cart

This air track glider has a heavy pendulum; when the pendulum is set swinging the glider moves in the opposite sense.

M-d4e

Air Track Inchworm

Two air track gliders coupled by a spring will oscillate about the center of mass that is marked by a flag.

Central Forces

M-d5a

Orbit Ball

This consists of a large and a small ball attached to opposite ends of a string which passes through a metal handle. The light ball is twirled and the centripetal force is provided by the weight of the heavy ball.

M-d5b

Conical Pendulum

Three balls, suspended by differing lengths of string from the same height on a rotating shaft, rotate in the same horizontal plane.

M-d5c

Swing the Bucket

Swing a bucket of water in a vertical circle and then in a horizontal circle over your head.

M-d5e

Chain Wheel

A loop of chain is rotated very fast and then released onto the demo table, where it runs over obstacles while retaining its circular form.

Deformation by Central Forces

M-d5k

Rotating Tank

A large but thin, clear rectangular box is half-filled with colored water and rotated. The water surface forms a parabola.

Centrifugal Escape

M-d5n

Ball and Hoop

A hoop that confines a ball to a circular orbit is suddenly removed

M-d5m

Tangential Velocity

This demo uses an apparatus that rotates a ball on a string and that provides a means to cut the string while the ball is in flight.

Projectile Motion

M-d6b

Jumping Block -- Air Track

A ball projected vertically upward from a moving air track glider falls back into the muzzle.

M-d6c

Jumping Ball on Cart

A ball projected vertically upward from a wheeled cart falls back into the muzzle.

M-d6f

Balls Shot and Dropped -- Classroom version

A ball is dropped and simultaneously another is projected horizontally; they hit the floor at the same time.

M-d6d

Balls Shot and Dropped -- Lecture Hall

A ball is dropped and simultaneously another is projected horizontally; they hit the floor at the same time. [May conflict with Shoot-the-Monkey and Timed Free Fall.]

M-d6h

Mini Shoot the Monkey

A minified version of the shoot-the-monkey demonstration.

M-d6i

Shoot the Monkey -- Classroom version

A shoot-the-monkey demo suitable for a normal size classroom

M-d6e

Shoot the Monkey

An air-gun shoots at a monkey, released when the air-gun is fired; the bullet hits the monkey in mid-air. [May conflict with Timed Free Fall or Balls Shot and Dropped.]

M-d6g

Range of a Gun

Shoot at 45, then calculate 30 or 60 and place the target

Relative Motion

Moving Reference Frames

M-e1a

Crossing the River

A battery powered tank runs at constant speed on a sheet of paper that is pulled in a direction perpendicular to the tank's velocity.

Coriolis Effect

M-e3a

Deflecting Water Stream

Watch a horizontally-ejected stream of water falling into a pan, all mounted on a rotating platform, when the whole starts to rotate.

Newton's First Law

Inertia of Rest

M-f2a

Inertia Masses

A 100 g mass is suspended from a 1 kg mass which is suspended from a crossbar. A sharp downward pull breaks the lower thread; a slow pull the upper thread.

M-f2b

Hammered Blocks

The bottommost of a stack of blocks, when struck sharply, will slide to the side while the upper blocks remain in place.

Inertia of Motion

M-f3a

Glider on Level Air Track

A glider on a level air track persists in gliding.

Newton's Second Law

Force, Mass, and Acceleration

M-g1d

Second Law--Fan Propelled Cart

Measure the final speed of a fan-propelled (constant acceleration) cart whose mass can be varied.

M-g1a

Spring-Pulled Air Cart

An air track glider is pulled by a spring held at constant extension.

M-g1b

Newton's Second Law on air track

An air track glider whose weight can be varied is attached to one end of a spring that has its other end fixed. The glider is pulled back and released; a photogate records its transit time at one point before the glider collides with the compressed spring.

M-g1c

Atwood's Machine

Two equal masses are hung from a pulley. A small amount of mass is transferred from one side to the other.

Accelerated Reference Frames

M-g2a

The "Anti-Gravity" Plumb Bob

A balloon filled with helium is suspended from the bottom of a box and the box is pushed.

Newton's Third Law

Action and Reaction

M-h1c

3rd Law with Scales

Pull on two coupled spring scales with springs of equal or unequal strength.

M-h1a

Push Me Pull Me Carts

Two people stand on roller carts and both pull on a rope or push with a long stick.

M-h1d

Fan Cart with Sail

A cart with a sail propelled by a battery powered fan shows interesting third law behavior.

Recoil

M-h1b

Tennis Ball Cannon

A cannon mounted on an air track glider shoots out a tennis ball horizontallly.

Statics of Rigid Bodies

Finding Center of Gravity

M-j1a

Hanging Shapes

Suspend a 2-dimensional shape from holes drilled near the edges, and use a plumb bob to find the center of gravity.

M-j1d

Meter Stick on Fingers

Slide fingers together under a meter stick to come together at center of mass. Repeat with mass attached to one end of stick.

Exceeding Center of Gravity

M-j1b

Photo: Pisa's Leaning Tower

Digital image of the photo from Bloomberg's sixth floor of the Leaning Tower of Pisa. May be projected in the auditorium.

M-j1c

Center of Gravity Blocks

Stack blocks stairstep fashion at the edge of the table until the topmost block sticks out beyond the table edge.

Stable, Unstab., and Neut. Equil.

M-j2a

Stable and Unstable Equilibria

Two large rings each with two masses that have radially adjustable positions. By positioning both at same end, stable and unstable equilibrium can be shown.

Stable and Unstable Equilibrium

M-j2b

Tight Rope Walker

The Tight Rope Walker consists of a pulley with four heavy lead weights on long semi-stiff wires symmetrically mounted around it. When placed on the "rope" (Cord), the weights hang down well under the rope, leaving the center of the Walker's mass below the rope and thus making it easy for the Walker to keep its balance.

M-j2c

Tilted pop can

A partially-filled pop when tilted appropriately will remain tilted.

Resolution of Forces

M-j3a

Suspended Block

A 1 kg mass rests on a 3-4-5 incline (e.g. incline angle = arctan(3/4)). Forces parallel and perpendicular to the incline will support the mass in mid-air when the incline is removed.

M-j3d

Four scales in a row

A mass is hung at the end of a series of spring scales

M-j3c

Rope and three students

Two large strong students pull on the ends of a rope and a small student pushes down in the middle.

M-j3b

Force Board

This is a circular, ruled force table with four moveable pulleys arranged around the edge; four strings pull on a ring in the middle with masses hanging from each string. Used to show the vector sum of forces.

Static Torque

M-j4a

Torque Bar

A long thin rid mounted perpendicular to a bar handle holds a 2 kg mass on a sliding collar.

M-j4d

Wrench, Nut, and Bolt

Use a wrench, nut, and bolt to illustrate torque.

M-j4b

Equal Arm Balance

Combinations of weights and distances on either side of the fulcrum of the equal arm balance may be selected to produce equilibrium. An oblique arm is used to show that the effective length of the lever arm is set by the component of the force.

M-j4c

Mass on Bar between Scales

A horizontal beam with a sliding 1 kg mass is hung between two spring scales.

Applications of Newton's Laws

Dynamic Torque

M-k1a

Pushing the Refrigerator

Depending on where a large rectangular box is pushed, it will slid, tip, or turn.

M-k1b

Ladder against a Wall

Set a ladder against the wall and walk up the rungs until the ladder begins to slide.

Friction

M-k2a

Friction Cars on Inclined Plane

The static or dynamic forces required to move teflon-coated, rubber-coated, and wooden carts on an inclined plan are displayed on a spring scale

Pressure

M-k2d

Bed of Nails

Lie down on a bed of nails.

Gravity

Univ. Gravitational Constant

M-L1a

Cavendish Balance Video

Time lapse of the Cavendish Experiment on Videodisk.

Orbits

M-L2a

Gravitational Well

A large fiberglass vortex-shaped cone is used to show circular and elliptical orbits and conservation of angular momentum.

M-L2c

Satellite Launch Applet

Animation launching a satellite tangentially to earth surface, as function of velocity: http://www.phy.ntnu.edu.tw/ntnujava/viewtopic.php?t=24

M-L2b

Styrofoam cup -- conic sections

A cone is cut in circular, elliptical, parabolic, and hyperbolic cross sections.

M-L2d

Kepler's Laws Applet

Animation illustrating Kepler's first, second, and third laws: http://www.phy.ntnu.edu.tw/ntnujava/viewtopic.php?t=25

Work and Energy

Work

M-m1a

Pile Driver

Drive a nail into a block of wood with a pile driver.

Simple Machines

M-m2b

Compound Pulley

Weights of a proportion of 5-to-1 are the equilibrium conditions for this compound pulley.

M-m2a

Simple Pulley

Show a simple pulley in equilibrium

Work-Energy Theorem

M-m2c

Spring Launched Cart on Level Track

A spring (of measurable spring constant) launches a cart (with measurable final veloctiy) on a level air track. Mass of cart can be varied.

Non-Conservative Forces

M-m3a

Decelerated Pendulum Rider

A pendulum hits a level board, transferring a mass rider that slides to a stop.

Conservation of Energy

M-m4a

Bowling Ball Pendulum

A bowling ball pendulum is pulled back until it touches the lecturer's nose and let go. The lecturer does not move.

M-m4b

Galileo's Pendulum and Nail

A pendulum started at the height of a reference line reaches the same height when its swing is intercepted by a post that effectively shortens the length of the pendulum.

M-m4c

Loop the Loop

A rolling ball must be released from a height equal to 2.7 times the radius of the loop.

M-m4d

Ballistic Pendulum with Gun

A ball is shot out of a fixed, spring-powered gun into a pendulum which traps the ball.

M-m4e

Spring Launched Air Cart

Predict the height to which a spring-compressed glider will rise on an inclined air track given the mass, spring constant, and amount of spring compression. Do the experiment.

M-m4f

Spring-Launched Rolling Cart

Predict the height to which a spring-compressed cart will rise on an inclined plane given the mass, spring constant, and amount of spring compression. Do the experiment.

M-m4g

Rattleback

The rattleback, or celt, will slow down and reverse direction when rotated against its preferred rotational direction.

Linear Momentum and Collisions

Impulse and Thrust

M-n1a

Lacrosse Ball Compression/Impression

Drop a lacrosse ball on down-ward facing carbon paper, and then press down on the ball until it is squashed the same amount.

M-n1b

Egg in sheet

Throw an egg into a sheet held by two people.

Conservation of Linear Momentum

M-n2d

Spring apart air track gliders

Cut a string between two air track gliders compressed by a spring. Either 150g carts, 300g carts, or one of each can be used.

M-n2c

Spring apart Pasco carts

Tripping the spring between two Pasco carts launches them in opposite directions; the cart masses may be varied.

Rockets

M-n2a

Fire extinguisher wagon

Mount a fire extinguisher on a cart and take a ride.

M-n2b

Water Rocket

A toy rocket is launched twice, once when pumped up with air and once when pumped up with water.

Collisions in One Dimension

M-n3a

Newton's Cradle

Five adjacent metal balls on a bifilar suspension illustrate momentum conservation properties.

M-n3c

Elastic Collisions on Air Track

Elastic collisions between air track gliders of equal and/or unequal mass.

M-n3d

Inelastic Collisions on Air Track

Inelastic collisions between air track gliders of equal and/or unequal mass.

M-n3e

Supernova

A tennis ball is placed on top of a basketball and both are released from rest.

M-n3f

Astroblaster

Four balls of progressively smaller diameter resting on top of one another are dropped to the floor.

Collisions in Two Dimensions

M-n4a

Air Table

Can use to illustrate the properties of momentum in two dimensions with these pucks that glide freely over an air table.

Rotational Dynamics

Moment of Inertia

M-q1a

Inertia Wands

Students twirl equal mass wands, one with the mass concentrated in the middle, the other with the mass concentrated at the ends.

M-q1b

Ring versus Disk Race

The Matched Disk and Ring are identical in diameter and mass. When rolled down the inclined plane, the disk wins the race due to its lower moment of inertia.

M-q1c

Racing Disks

Two disks of identical mass, one weighted in the center and the othe weighted at the rum, are rolled down an incline.

M-q1d

Racing cylinders

3 Cylinders of identical mass and appearance accelerate down an incline at different rates.

Rotational Energy

M-q2a

Whirlybird

Two equal masses with adjustable positions are mounted on a radial bar fixed to a horizontal axis with a pulley. A weight on a string rotates the assembly.

M-q2b

Massive Atwood's Machine

Atwood's machine with a large, massive pulley.

M-q2c

Toppling Chimney

A column of two sticks, one on top of the other, is pushed until it topples

Conservation of Angular Momentum

M-q4f

Collapsing Star

Collapse a spinning suspended Hoberman Sphere into a small ball.

M-q4a

Rotating Platform and Weights

Spin on a rotating platform with a dumbbell in each hand.

M-q4b

Swinging Bat on Rotating Platform

Stand on a rotating platform initially at rest, and swing a bat or a mallet.

M-q4c

Bike wheel on rotating platform

Invert a spinning bicycle wheel while standing on a rotating platform.

M-q4d

Rotating Platform and Mallet

Rotate yourself one full revolution using a mallet.

M-q4e

Angular Momentum Funnel

The angular speed of a ball bearing increases as it approaches the bottom of a large glass funnel.

Gyros

M-q5f

Throwing Top

A classic throwing top

M-q5a

Precessing Disk

Spin a metal disk on a nail inserted in a central hole and touch a finger to the rim. [Broken]

M-q5b

Toy Gyroscope

The toy gyroscope has a knob on the end of an axis that fits into a hollow in a separate mound. Useful demo for a small classroom.

M-q5c

Bicycle Wheel Gyro

The bike wheel is hung from its axle by a wire attached to the ceiling; when spun the bike wheel illustrates gyroscope motion nicely.

M-q5d

MITAC Gyroscope

This motorized gyroscope, used in the teaching labs, is good for showing a gyroscope's directional constancy; can also show precession due to applied torques.

M-q5e

Gimbaled Gyroscope

An old aircraft navigational gyroscope that spins fast and shows the gyroscope's ability to maintain its orientation in space

Rotational Stability

M-q6a

Good, Bad, and Giant YoYos

Comparison betwen well and poorly designed yoyos.

Properties of Matter

Tensile and Compressive Stress

M-r2a

Breaking Wire

Suspend a wire from the ceiling and add masses until the wire breaks.

M-r2b

Young's Modulus

Hand weights from a wire, and use a laser and mirror-mounted-on-lever to display the elongation.

M-r2c

Poisson's Ratio with rubber tube

The striped tube can be stretched to show lateral contraction with increasing length.

Shear Stress

M-r3a

Deformation of Thick Book

The large book can be pushed perpendicular to the spine to show shear.

M-r3b

Striped Tube Twist

The striped tube can be twisted to show torsion.

Coefficient of Restitution

M-r4b

Atomic Trampoline

Compare a steel ball bouncing on an amorphous metal to one bouncing on stainless steel.

M-r4a

Happy and Unhappy Balls

Two black rubber balls of about 1.5 cm diameter are dropped from a height simultaneously. One ball bounces high while the other barely rebounds. Great to pass around.

Crystal Structure

M-r5a

NaCl crystal model

NaCl model made of wooden balls connected by metal sticks.

Fluid Mechanics

Surface Tension

Force of Surface Tension

F-a1a

Floating Metals

Float a razor blade, a paperclip, and a needle on the surface of water.

Minimal Surface

F-a1b

Ring and Thread

A loop of thread inside a soap film forms a circle when the film interior to the loop is popped.

Capillary Action

F-a2a

Capillary Tube

Compare the height of water in different diameter tubes

Statics of Fluids

Static Pressure

F-b2a

Pascal's Vases

Tubes of different geometries rise vertically out of a common reservoir of colored water.

F-b2f

Hydraulic Press

Break a piece of wood in a hydraulic press. [BROKEN summer 2005]

Atmospheric Pressure

F-b3d

Indent the Can--cooling of air

Heat the air inside the can until it's hot, cap, and remove from heat.

F-b3c

Crush the Can--water condensation

Heat water in a can until boiling, then cap and remove from heat.

F-b3a

Crush the Can--with pump

A vacuum pump evacuates a 1 gallon can; atmospheric pressure crushs the can.

F-b3b

Magdeburg Disks

Evacuate Magdeburg hemispheres and try to separate them.

F-b3e

Vacuum Cannon

Puncture the packing tape that seals each end of an evacuated PVC tube containing a ping pong.

Density and Buoyancy

F-b4a

Weigh Submerged Block

A 2 kg Al cylinder, suspended from the 20 N spring scale, is lowered into water and the new weight is observed; Can have beaker on scale; Can lower into oil for comparison

F-b4f

Ice Melting in Water

Show that the water level doesn't change when the ice in a beaker of ice water melts.

F-b4b

Cartesian Diver

Squeeze the bottle to sink the diver.

F-b4d

Coke and Diet Coke

An unopened diet soda can floats in water, and a regular soda can sinks.

F-b4c

water and oil "U" tube

Water and oil rise to different heights in a "u" tube.

F-b4e

Floating Balloons

Helium filled ballons trailing masses float without rising or sinking.

Dynamics of Fluids

Bernoulli Force

F-c2a

Venturi Flowmeter

Air flows through a restricted glass tube to the atmosphere; the pressure at different points of the tube is shown by manometers.

F-c2b

Floating Ping Pong Ball

A ping pong ball floats in an upward stream of air.

F-c2c

Funnel and Ball

A ping-pong ball is supported by air streaming out of an upside down funnel.

F-c2d

Windbag

Blow up an 8-foot long bag with one breath.

F-c2f

Curving Baseball

A relatively complicated apparatus that holds and spins a ping pong ball and has an attachment to hit the ball, resulting in a curved trajectory.

F-c2e

Ping Pong Ball and Racket

Use a ping pong racket to hit a curve ball using a 2-3" diameter styrofoam ball or a ping pong ball.

Viscosity

F-c3a

Ball Drop in Oil

A steel ball is dropped into a tall cylinder filled with water and then with corn syrup.

F-c3b

terminal velocity--coffee filters

Drop a coffee filter and it descends at a low terminal velocity. Crumble it and it free falls.

F-c3c

Coffee Filter Drop

One coffee filter dropped from one meter and four coffee filters dropped from 2 meters hit the ground at the same time, demonstrating that the drag force is proportional to the square of the velocity

Turbulent and Streamline Flow

F-c4a

Mixing-Unmixing

Two concentric cylinders, separated by corn syrup and with a line of dye in the syrup parallel to the axis, can be rotated and "unrotated" to restore the line of dye. [Broken]

Oscillations and Waves

Oscillations

Pendula

W-a1a

Simple Pendulum

A bob on a string hanging from a stand exhibits simple harmonic motion for small angles.

W-a1b

4-to-1 Pendula

One pendulum four times longer than a second oscillates with twice the period of the second.

W-a1c

Different mass pendula

Three pendula of different masses but the same length all oscillate with the same period.

W-a1d

Torsion Pendulum

A steel cylinder is suspended by a steel music wire along its right axis. When the cylinder is displaced by rotation and released it will oscillate in simple harmonic motion.

W-a1e

Pendula Amplitude Dependence

Two identical simple pendula set in motion with different initial amplitudes, oscillate nonisochronically.

Springs and Oscillators

W-a2a

Spring and Weight

A mass hangs on the end of a spring. Using two springs of different k and a variety of masses, show the effect of varying k and m.

W-a2d

Springs in Series and Parallel

A spring with mass m, two identical springs in parallel with mass 2m, and two identical springs in series with mass m/2 oscillate with the same period.

W-a2b

Spring and Air Cart

An air track glider is attached to a horizontal spring and displaced from equilibrium.

W-a2c

Air track glider and Spring

Two identical air track carts are attached to (opposite) ends of an air track by means of two different springs. A mass may be added to either cart, and the dependence of the oscillation frequency on mass and on spring constant may be explored.

Simple Harmonic Motion

W-a4a

Projected SHM

Shadow project a ball mounted on a rotating disk.

W-a4b

Projected SHM Applet

Java Applet relating circular motion to a mass on a spring: http://www.phy.ntnu.edu.tw/ntnujava/viewtopic.php?t=13

Driven Mechanical Resonance

W-a6a

Tacoma Narrows Film

A 4.40 minute video of the collapse of the Tacoma Narrows Bridge. Very impressive and memorable.

W-a6b

Driven Cart Between Springs

An air track glider attached by springs to an mechanical oscillator, is swept through resonance.

W-a6c

Damped Driven Hanging Mass

A mass, supported by a spring whose support is driven, vibrates against a solid screen; the drive amplitude, frequency and the screen angle can be varied.

Coupled Oscillations

W-a7a

Wilberforce Pendulum

Illustrates the transfer of energy between torsional and vertical oscillation modes.

W-a7b

Coupled Pendula

Two pendula are coupled with a light spring.

Non-Linear Systems

W-a9k

Amplitude Jumps

An air cart is driven between two springs. A magnet on top interacts with other magnets to perturb the potential and produce the jump effect.

W-a9m

Chaotic/Anharmonic Pendulum

A physical pendulum made of a ruler blade oscillates between between two disk magnets. This is a modification of a pendulum in the advanced lab.

W-a9n

Two Uncoupled, Physical Double Pendula

Two uncoupled, physical double pendula, each having one bob hanging from an upper bob, are used do demonstrate chaos.

Wave Motion

Transverse Pulses and Waves

W-b1a

Pulse on 1.9m spring

Give the 1.9 m spring a quick pulse. The length and/or tension in the spring can be varied. Good for showing pulses, standing waves, harmonics, energy transfer.

W-b1b

Pulses on Torsional Wave Apparatus

Excite each of the three torsional transverse wave machines by hand to show how the wave speed varies as the inertia of the medium (the rod lenght) varies.

W-b1c

Reflection--Torsional Wave Apparatus

Send pulses down a Shive wave model machine with the other end free, then fixed.

Longitudinal Pulses and Waves

W-b2a

Hanging Slinky

A long slinky is supported on a bifilar suspension, and the ends are taped to the lab stands, for showing longitutinal wave properties with minimal friction. [BROKEN]

W-b2b

Slinky

Two students stretch a slinky and send longitudinal waves down the slinky.

Standing Waves

W-b2e

Driven Rope Waves

A horizontal rope with a mechanical vibrator at one end and a weight over a pulley at the other end is used to show standing waves at different driving frequencies.

Inpedance and Dispersion

W-b2k

Joined spring and cord

The 1.9 m spring is attached to a rubber cord; pulses started at one end will produce both transmitted and reflected pulses.

W-b2m

Pulse over trough edge

A slinky lies in a tilted channel raised above the table; pulling one point of the slinky onto the table causes a pulse to propagate along the channel, in mechanical analog to nerve conduction along axons.

Compound Waves

W-b2r

Wave Superposition -- Torsional Wave Apparatus

Send pulses simultaneously from both ends of one section of the torsional wave machine.

W-b2p

Wave Superposition--Long Spring

Send pulses simultaneously down both ends of the 1.9 m spring to show the addition of amplitudes.

W-b2q

Wave Superposition -- on scope

Electronically add two 440 Hz sine waves of different phases together on the scope and audibly.

Wave Properties of Sound

W-b3a

Bell in a Vacuum

An alarm buzzer is suspended inside an evaculated bell jar, turned on, and the bell jar is evaculated. When air is let back into the jar, the sound returns.

W-b3c

Speaker and Candle

A large speaker operating at low frequncy and large amplitude makes a candle flame oscillate.

W-b3b

Helium in recorder

Fill your lungs with helium and then talk, sing, or blow a musical instrument.

Doppler Effect

W-b4a

Doppler Buzzer

Swing a small battery powered buzzer on the end of a string in a circle over your head.

W-b4b

Doppler in Ripple Tank

Move the wave generator back and forth in the ripple tank.

W-b4c

Doppler with Stroked Aluminum Rod

Shake the stroked aluminum rod at the audience

Interference and Diffraction

W-b5a

Single Slit in Ripple Tank

Diffraction from a plane wave passing through a single slit on the ripple tank mounted on the overhead projector.

W-b5c

Two Points in Ripple Tank

Two point source generators of ripples show interference patterns in the ripple tank on the overhead projector.

W-b5d

Double Slits in Ripple Tank

A plane wave impinges on a barrier with two slits in the ripple tank on the overhead projector.

W-b5b

Moire Pattern Transparancies

Transparancies with identical concentric circular patterns are placed on top of each other with a slight offset.

Interference and Diffraction of Sound

W-b5e

Two-Speaker Bar

A 2 meter long bar with a speaker at each end produces auditory interference patterns.

W-b5f

Baffle and Speaker

Listen to a single bare speaker, then surround it by a baffle.

Beats

W-b6a

Beats with Tuning Forks

Two tuning forks of identical frequency are mounted on resonant enclosures; when a small piece of wax is attached to one, beats can be heard.

W-b6b

Beats on Scope

Two audio signals are fed through a summing amplifier and the result is presented on the oscilloscope and a speaker.

Coupled Resonances

W-b7a

Coupled Tuning Forks

Strike one of two matched tuning forks mounted on resonant boxes and the other vibrates too.

Acoustics

Wave Analysis and Synthesis

W-c5d

Java Fourier Synthesizer NTNU

Construct, hear, and see waveforms built from up to fifteen harmonics: http://www.phy.ntnu.edu.tw/java/sound/sound.html

W-c5f

Java Fourier Synthesizer Thole-Huber

Construct any waveform by specifying numerically up to 13 fourier components or inputing the analytical expression, and hear and see the resulting waveforms. built from up to over a hundred harmonics: http://homepages.gac.edu/~huber/fourier/

W-c5a

Pasco Fourier Synthesizer

Construct, hear, and see waveforms built from the 440 Hz fundamental and up to eight harmonics.

W-c5e

Java Fourier Synthesizer Falstad

Construct, hear, and see waveforms built from up to over a hundred harmonics: http://www.falstad.com/fourier/j2

W-c5b

Fourier Analyzer

Use the FFT module of the Tektronix TDS3014 oscilloscope to examine the waveform and spectrum of sound waves.

W-c5c

Resolution of Fourier Analyzer

The width of the Fourier transforms depends on the length of the wave being analyzed and limits the resolution of the spectrum.

Instruments

Resonance in Strings

W-d2a

Guitar

Hanging weights on the end of a "guitar" can be varied to "tune" the guitar to a desired pitch.

Resonant Cavities

W-d3a

Resonant Tube

A long tube is rolled in front of a speaker driven by a sine wave generator to show resonance. A microphone probe shows pressure variations on the o-scope.

W-d3d

Bloogle

Whirl a corrugated plastic tube to produce sound. At least five tones can be heard.

W-d3g

Ruben's Tube

Show nodes and antinodes with the flames coming from a row of holes in a hollow tube filled with propane.

W-d3f

Kundt's Tube

Sawdust in a tube piles up at standing-wave nodes when driven by rubbing a rod attached to a disc.

Air Column Instruments

W-d3b

Organ Pipe

A closed-end, square wood organ pipe of adjustable length.

W-d3e

Conical Organ Pipes

A collection of conical pipes.

W-d3c

Trombone

A student-class trombone illustrates the effect of pipe length on resonant frequencies.

Resonance in Plates, Bars, Solids

W-d4c

Chladni Plates

A driven Chladni plate covered with sand shows standing wave patterns. Noisy!

W-d4d

Stroked Aluminum Rod

An aluminum rod sings when stroked with rosin-covered fingers.

Thermodynamics

Thermal Properties of Matter

Solid Expansion

H-a3a

Bimetallic Strip

Strips of dissimilar metals bonded together bend when heated. Makes a nice thermometer.

H-a3b

Ball and Ring

The Ball will pass through the hole in the brass plate (termed the ring) when both are at room temperature. When the ball is heated with the torch it expands and will not pass through the ring.

Heat and the First Law

Heat Capacity and Specific Heat

H-b1a

Calorimeter and Steel Mass

The heat capacity of a 1 kg steel mass is measured by calorimetry.

H-b1b

Metals Sinking into Wax

Hot copper, lead, and aluminum cylinders at a common temperature are placed on a wax block.

Convection

H-b2a

Convection Tube

One side of a glass tube loop is heated while a drop of ink is inserted in the other side.

Conduction

H-b3a

Melting Wax on Rods

Three metal rods (Cu, Al, Steel), with wax mounted on the ends of each, radiate horizontally from a central heated disk. This is a race to see which melts first.

Radiation

H-b4b

Light the Match

A match at the focus of one parabolic mirrir is lit by a heating element at the focus of another parabolic mirror.

H-b4a

Black and White Radiation

A thermopile with indicator is held to both sides of a hot coffeepot with one side painted black and the other side white.

Mechanical Equivalent of Heat

H-b6a

Dropping Lead Shot

One kg of lead in a 1 m long tube is inverted repeatedly and the temperature rise is measured.

H-b6b

Stretching Rubber Band

Stretch a rubber band or balloon and feel the heat generated with your lips.

Adiabatic Processes

H-b7a

Fire Syringe

A small (2mm x 2mm) piece of tissue is put at the bottom of the "fire torch," a clear glass cylinder that is closed at one end. When a plunger is inserted into the open end and rapidly pressed inwards, the tissue bursts into flames. [BROKEN]

H-b7b

Quickly Plunging Plastic Piston

A thermocouple embedded in a cylinder-and-piston assembly causes a galvanometer deflection when the cylinder is pressurized.

Change of State

PVT Surfaces

H-c1a

PVT Surfaces

Three dimensional models, about 25 cm on a side, of the PVT surfaces for water and carbon dioxide.

Phase Changes: Liquid-Gas

H-c3a

Boiling by Cooling

Use ice to cool a stoppered flask of hot water until boiling starts.

Cooling by Evaporation

H-c3b

Cryophorus

When one end of a glass tube with bulbs at each end containing water is placed in liquid nitrogen, the water at the other end starts to freeze.

H-c3c

Drinking Bird

This toy bird keeps bobbing its head in water because the evaporative cooling and internal pressure differences force the liquid inside above its center of mass, whereupon it tips, momentarily restoring equilibrium.

Sublimation

H-c4a

Carbon Dioxide Sublimation

A balloon filled with gaseous carbon dioxide is immersed in liquid nitrogen, sublimating the carbon dioxide to a solid and reducing the balloon to its original size.

Phase Changes: Solid - Solid

H-c4b

Memory Wire (Nitinol)

Heat a bent Nitinol wire with warm water and it springs back to its original shape

Kinetic Theory

Brownian Motion

H-d1a

Brownian Motion

The Brownian movement of smoke particles in air is projected onto a screen or wall for all to see.

H-d1b

Brownian Motion Applet

Browning motion java applet: http://www.phy.ntnu.edu.tw/ntnujava/viewtopic.php?t=41

Mean Free Path

H-d2a

Crookes' radiometer

Light shining on the "radiometer" makes the vanes spin, but in a direction opposite to that expected for light absorption and reflection.

Kinetic Motion

H-d3a

Vertical Molecular Motion Simulator

H-d3b

Equipartition of Energy--balls in cup

As this cup of balls is jostled manually with increasing fervor, first the cork, then the polystyrene, and finally the aluminum ball is knocked out.

H-d3c

Equipartition of Energy--vibrating frame

A vibrating frame with two collections of balls differing in mass is used to simulate gases of different molecular weights.

Diffusion and Osmosis

H-d5a

Ink in Water

A drop of ink diffusion slowly in water

H-d5b

Permeable Membrane--sucrose/water

Sucrose solution rises against atmospheric pressure driven by osmotic pressure.

Gas Law

Constant Pressure

H-e1c

Charles' Law--Piston Chamber and Flask

The piston rises and falls depending on whether the flask is heated or cooled.

H-e1a

Balloons in liquid nitrogen

Liquid nitrogen is poured over an air-filled balloon until it collapses.

H-e1b

Helium balloon in liquid nitrogen

Immerse a He balloon successively in graduated pyrex beakers of water and liquid nitrogen to measure its change in volume with temperature at constant pressure

H-e1d

Heat Engine--Piston Chamber and Flask

A mass on top of the piston is lifted when the flask is heated.

Constant Temperature

H-e2a

Boyle's Law--Piston Chamber and Flask

Vary the mass on top of the piston and observe the volume change

Constant Volume

H-e3a

Gay-Lussac's Law--Constant Volume bulb

The constant volume bulb is filled with helium at room temperature and pressure, then sealed. It is then immersed in boiling water, ice water, and liquid nitrogen (or in a alcohol/acetone bath).

Entropy and the Second Law

Heat Cycles

H-f3b

Carnot Cycle Simulation

Carnot Cycle Java Applet: http://www.phy.ntnu.edu.tw/ntnujava/viewtopic.php?t=40

H-f3a

Stirling Engine

An excellent, simple, working model of the Stirling engine.

Electricity and Magnetism

Electrostatics

Producing Static Charge

EM-a1a

Frictional Electricity

An electroscope is charged using charged rods.

EM-a1b

Electrophorus

The top plate of an electrophorus is charged by induction.

EM-a2a

Charged Rods on Pivots

A charged rod on a pivot is used to show attraction and repulsion by another charged rod.

EM-a2c

Party balloon on wall

Rub a balloon against your hair or wool shirt and stick it on the wall.

Electrostatic Meters

EM-a2b

Conductive Balls

Two lightweight conducting spheres suspended by nylon thread can be used as charge indicators

Conductors and Insulators

EM-a3a

Conductors and Insulators

Shows that charge can be transferred to an electroscope through conductors but not insulators

Induced Charge

EM-a4a

Electroscope Charged by Induction

Charge an electroscope by induction.

EM-a4b

Charged Rods and Aluminum Can

A charged rod can be used to pull a soda can by electrostatic induction

EM-a4c

Deflection of stream of water

A charged rod deflects a stream of water.

Electrostatic Machines

EM-a5a

Wimshurst Machine

Generate sparks with a Wimshurst Machine, and explain its workings.

Electric Fields and Potential

EM-a5b

Van de Graaff Generator

Describe the operation of the Van de Graaff and show sparks from the ball to a nearby grounded conductor.

EM-a5c

Van de Graaff Generator--Sound

The engine strains more and more as the charge on the dome increases.

Electric Fields

EM-b1a

Oscilloscope

Show that an electron beam passing between charged, parallel plates is deflected using an oscilloscope.

EM-b1b

Hair on End

Charge yourself with a Van de Graaff generator

EM-b1c

Styrofoam Peanut Blowout

Styrofoam peanuts in a box on top of the Van de Graaff fly out.

EM-b1e

Tart Pan Blowoff

Tart pans stacked on top of the Van de Graaff fly off.

EM-b1h

Popcorn blow-off

A fake--Pour unpopped popcorn into a bucket on the van de graaff and popped popcorn flies out.

EM-b1f

Ball Charge Transfer

A conductive ball bounces between electrically charged horizontal plates

Electric Field

EM-b1d

Electric Field Visualizer

Tiny fibers in a clear oil align in the direction of strong applied electric fields.

EM-b1k

Visualizing Field Lines in a Capacitor

Use the Electric Field Visualizer with two parallel conductors to show the field lines for a capacitor including edge effects

EM-b1g

Torque on Electric Dipole

A small rod aligns between parallel plates

Gauss' Law

EM-b2a

Faraday Bucket

Show that charge resides on the outside of a hollow conductor.

EM-b2f

Gauss with Electric Field Visualizer

Tiny fibers in a clear oil that align in the direction of strong applied electric fields remain randomly oriented inside a charged ring.

EM-b2b

Radio in a Cage

Surround a radio by a Faraday cage and the signal goes away

Electrostatic Potential

EM-b3a

Surface charge density - balls

Separate two pairs of balls of different radius but same separation are attached to and charged simultaneously with the Wimhurst.

EM-b3c

Charged Ovoid

Use a proof plane and an electroscope to compare charge densities at different points on an egg-shaped conductor.

EM-b3g

Lightning Rod

Electrical arcing between two large metal spheres abruptly ceases when the lightning rod is touched to one.

EM-b3d

electric wind with Wimhurst

A point attached to the Wimhurst electrodes blows a candle flame.

EM-b3f

Electric Wind with Van de Graaff

A point attached to the Van de Graaff blows a hanging peice of cardboard.

EM-b3e

Van de Graaff Pinwheel

A pinwheel rotates on top of a van de Graaff generator.

Capacitance

Capacitor

EM-c1a

Parallel Plate Capacitor

Vary the spacing of a parallel plate capacitor attached to an electroscope.

EM-c1b

Rotary Plate Capacitor

The rotary plate capacitor is attached to the electroscope.

Dielectric

EM-c2a

Parallel Plate Capacitor with Dielectric

Insert and remove a dielectric sheet from a charged parallel plate capacitor attached to an electroscope.

EM-c2c

Force on a dielectric

Mineral oil climbs in the gap between parallel plates

EM-c2b

Dissectable Capacitor

This curious capacitor is charged, disassembled, passed around, assembled, and discharged with a spark.

Energy Stored in a Capacitor

EM-c3a

Explosive Capacitor Discharge

Discharge a 10kV, 1uF capacitor through a thin wire or thick screwdriver

EM-c3c

Bulb and 1 Farad Capacitor with DVM

A large (1 Farad) capacitor is charged with a battery then discharged through a light bulb, with output monitored with DVM

EM-c3d

Bulb and 1 Farad Capacitor with Oscilloscope

A large (1 Farad) capacitor is charged with a battery then discharged through a light bulb, with output monitored with an oscilloscope.

EM-c3b

Bulb and 1 Farad Capacitor

A large (1 Farad) capacitor is charged with a battery then discharged through a light bulb.

Resistance

Resistance Characteristics

EM-d1a

Wire Resistivity

Place 6V across a set of wires of different diameters and measure the currents.

Resistivity and Temperature

EM-d2a

Change of Resistance with Temperature

A coil in series with a lamp is immersed in liquid nitrogen making the lamp glow brighter.

EM-d2b

Carbon Resistor in Liquid Nitrogen

Drop a resistor in liquid nitrogen and measure its resistance.

EM-d2c

Conduction in Glass

Heat a glass rod with a flame until its resistance is low enough to sustain conduction.

Conduction in Gases

EM-d4a

Jacob's Ladder

An arc rises between rabbit ear electrodes attached to a hig