Physics Lecture Demonstrations
Demonstrations suggested for the text
Physics, 5th ed., by
Resnick, Halliday, and Krane
Revised Fri Oct 3 14:29:00 2003
||Powers of Ten
||"Powers of Ten" is a 9 minute film spanning scales from the edge of the universe to the sub-atomic
||A replica of the platinum-iridium bar in Paris that was the international standard for length before 1960.
Chapter2--Motion in One Dimension
||Magnetic Blackboard Vectors
||A set of magnet-backed vectors of lengths 3, 4, and 5 used to show vector addition on the blackboard.
||Tank on moving sheet
||A battery powered tank runs at constant speed on a moving paper to show how velocities add and subtract.
||Dime and Feather Tube
||A penny and a feather fall freely inside a glass cylinder that can be evacuated.
||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.
Chapter3--Force and Newton's Laws
||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.
||The bottommost of a stack of blocks, when struck sharply, will slide to the side while the upper blocks remain in place.
||Fan Propelled Cart
||Measure the final speed of a fan-propelled (constant acceleration) cart whose mass can be varied.
||3rd Law with Scales
||Pull on two coupled spring scales with springs of equal or unequal strength.
||Push Me Pull Me Carts
||Two people stand on roller carts and both pull on a rope or push with a long stick.
Chapter4--Motion in Two and Three Dimensions
||Range of a Gun
||Shoot at 45, then calculate 30 or 60 and place the target
||Ball Drop in Oil
||A steel ball is dropped into a tall cylinder filled with water and then with corn syrup.
||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
||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.
||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.
||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.
||Ball and Hoop
||A hoop that confines a ball to a circular orbit is suddenly removed
||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.
||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.
Chapter5--Applications of Newton's Laws
||Two equal masses are hung from a pulley. A small amount of mass is transferred from one side to the other.
||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.
||Rope and three students
||Two large strong students pull on the ends of a rope and a small student pushes down in the middle.
||Weights of a proportion of 5-to-1 are the equilibrium conditions for this compound pulley.
||Friction Cars on Inclined Plane
||The static and dynamic forces required to move teflon-coated, rubber-coated, and wooden surfaced carts on an inclined plane are displayed on a spring scale.
||Three balls, suspended by differing lengths of string from the same height on a rotating shaft, rotate in the same horizontal plane.
||Swing the Bucket
||Swing a bucket of water in a vertical circle and then in a horizontal circle over your head.
||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.
||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.
||Egg in sheet
||Throw an egg into a sheet held by two people.
||Spring apart Pasco carts
||Tripping the spring between two Pasco carts launches them in opposite directions; the cart masses may be varied.
||Five adjacent metal balls on a bifilar suspension illustrate momentum conservation properties.
||A tennis ball is placed on top of a basketball and both are released from rest.
||Four balls of progressively smaller diameter resting on top of one another are dropped to the floor.
Chapter7--Systems of Particles
||Motion of an Extended Object
||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.
||Pendulum Air Cart
||This air track glider has a heavy pendulum; when the pendulum is set swinging the glider moves in the opposite sense.
||Air Track Inchworm
||Two air track gliders coupled by a spring will oscillate about the center of mass that is marked by a flag.
||Determining Center of Mass
||Suspend a 2-dimensional shape from holes drilled near the edges, and use a plumb bob to find the center of gravity.
||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.
||A toy rocket is launched twice, once when pumped up with air and once when pumped up with water.
||A long thin rid mounted perpendicular to a bar handle holds a 2 kg mass on a sliding collar.
||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.
||Students twirl equal mass wands, one with the mass concentrated in the middle, the other with the mass concentrated at the ends.
||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 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.
||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.
||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.
||Ladder against a Wall
||Set a ladder against the wall and walk up the rungs until the ladder begins to slide.
||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.
||A column of two sticks, one on top of the other, is pushed until it topples
||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.
||Two disks of identical mass, one weighted in the center and the othe weighted at the rum, are rolled down an incline.
||3 Cylinders of identical mass and appearance accelerate down an incline at different rates.
||Collapse a spinning suspended Hoberman Sphere into a small ball.
||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.
||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.
Chapter11--Energy 1: Work and Kinetic Energy
||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.
||Drive a nail into a block of wood with a pile driver.
Chapter12--Energy 2: Potential Energy
||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.
||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.
||High road low road
||Two balls race, one down a slight incline and the other down an identical incline containing a valley.
||Loop the Loop
||A rolling ball must be released from a height equal to 2.7 times the radius of the loop.
Chapter13--Energy 3: Conservation of Energy
||A large fiberglass vortex-shaped cone is used to show circular and elliptical orbits and conservation of angular momentum.
||Crush the Can
||A vacuum pump evacuates a 1 gallon can; atmospheric pressure crushs the can.
||Evacuate Magdeburg hemispheres and try to separate them.
||Tubes of different geometries rise vertically out of a common reservoir of colored water.
||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 also lower into oil for comparison
||Coke and Diet Coke
|| An unopened diet soda can floats in water, and a regular soda can sinks.
||Float a razor blade, a paperclip, and a needle on the surface of water.
||Ring and Thread
||A loop of thread inside a soap film forms a circle when the film interior to the loop is popped.
||Air flows through a restricted glass tube to the atmosphere; the pressure at different points of the tube is shown by manometers.
||Funnel and Ball
||A ping-pong ball is supported by air streaming out of an upside down funnel.
||Blow up an 8-foot long bag with one breath.
||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.
||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.
||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.
||A bob on a string hanging from a stand exhibits simple harmonic motion for small angles.
||One pendulum four times longer than a second oscillates with twice the period of the second.
||Different mass pendula
||Three pendula of different masses but the same length all oscillate with the same period.
||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.
||Shadow project a ball mounted on a rotating disk.
||Tacoma Narrows Film
||A 4.40 minute video of the collapse of the Tacoma Narrows Bridge. Very impressive and memorable.
||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.
||Two students stretch a slinky and send longitudinal waves down the slinky.
||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. Better than rope!
||Pulse Propagation (Inertia)
||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.
||Pasco Fourier Synthesizer
||Construct, hear, and see waveforms built from the 440 Hz fundamental and up to eight harmonics.
||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.
||Two Points in Ripple Tank
||Two point source generators of ripples show interference patterns in the ripple tank on the overhead projector.
||Moire Pattern Transparancies
||Transparancies with identical concentric circular patterns are placed on top of each other with a slight offset.
||A 2 meter long bar with a speaker at each end produces auditory interference patterns.
||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.
||Hanging weights on the end of a "guitar" can be varied to "tune" the guitar to a desired pitch.
||A closed-end, square wood organ pipe of adjustable length.
||A student-class trombone illustrates the effect of pipe length on resonant frequencies.
||A driven Chladni plate covered with sand shows standing wave patterns.
||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.
||Beats on Scope
||Two audio signals are fed through a summing amplifier and the result is presented on the oscilloscope and a speaker.
||Swing a small battery powered buzzer on the end of a string in a circle over your head.
Chapter20--The Special Theory of Relativity
Chapter22--Molecular Properties of Gases
Chapter23--The First Law of Thermodynamics
Chapter24--Entropy and the Second Law of Thermodynamics
Physics Lecture Demonstrations at
the Department of Physics and Astronomy
The Johns Hopkins University