269 Demos Found.
10101
Simple Pendulum
Mechanics
Mechanics, Period, Frequency, Pendulum, Measurement
Demonstrating oscillations and frequency of a basic pendulum.
10102
Cart on Slope
Mechanics
Mechanics, Gravity, Acceleration, Cart
A sonic sensor measures the position over time as a cart rolls down a slope. Its acceleration can be calculated by its trajectory.
10103
Feather and Penny
Mechanics
Vacuum, Gravity, Acceleration, Mechanics
We drop a penny and a feather inside a vacuum chamber. Without air resistance, they fall with the same acceleration.
10105
Monkey Shoot
Mechanics
Mechanics, Gravity, Reference Frames
Shooting a plastic dart at a stuffed animal; the dart is aimed directly at it and the animal is dropped the instant the dart is fired, so the dart hits the animal.
10106
Twin Pendula
Mechanics
Mechanics, Pendulum, Frequency, Period, Beats
Two nearly identical pendula are run side by side to show that even nearly identical oscillators will eventually go out of phase.
10107
First Law Disc Stack
Mechanics
Mechanics, First Law, Inertia
A stack of cardboard discs is placed on a desk. A ruler can be used to smack out the bottom disk, while the rest of the stack falls straight down.
10108
First Law Projectile Cart
Mechanics
Mechanics, Projectile, Cart, First Law
A moving cart launches a ball straight up and catches it again.
10109
Pendulum and Photogate
Mechanics
Mechanics, Pendulum, Period, Frequency
A pendulum swings through a photogate, tracking its period and frequency.
10110
The Kilogram
Mechanics
Mechanics, Mass
Two 1-kilogram weights are measured to show differences in mass.
10111
Mini Marble Monkey Shoot
Mechanics
Mechanics, Projectile, Gravity, Reference Frames
A marble hanging by an electromagnet is dropped and hit by a magnet that is launched from a ramp. The scenario is identical to the monkey shoot, but on a smaller and more easily modified model.
10112
Circular Motion on Overhead Projector
Mechanics
Mechanics, First Law, Circular Motion, Inertia
A ball is rolled in a cardboard circle on an overhead project. When an piece of the circle is removed, the ball follows a linear tangent path when exiting the circle.
10201
Third Law Skateboard
Mechanics
Mechanics, Third Law, Momentum
Bowling ball (or medicine ball) is tossed from a skateboard, with demonstrator being propelled in opposite direction.
10202
Force Between Charged Parallel Plates
Mechanics, Electromagnetism
Mechanics, Force, Charge, Electricity
A metal plate is hung above another plate, counterbalanced by equal weight. A Van de Graaff or Wimshurst generator charges the plates and they are pulled together.
10203
Friction Brick with Force Meter
Mechanics
Mechanics, Force, Friction, Weight
Laying various weights on a brick and dragging it with a force meter, noting the relationship between weight and force needed to drag (sliding friction).
10204
Friction on a Slope
Mechanics
Mechanics, Force, Friction
Laying a brick on a slope and seeing what angle it finally slides down at.
10205
Hooke’s Law
Mechanics
Mechanics, Hooke's Law, Spring, Force
Showing the extension of a spring with weights hanging on it.
10206
Parallel and Antiparallel Current
Mechanics, Electromagnetism
Mechanics, Electricity, Magnetism, Force, Current, Magnetic Field
We hang rods from wires and run high currents through them. If the currents of the two bars are parallel, they attract; if they are antiparallel, they repel.
10207
Whoosh Bottle Rocket
Mechanics
Mechanics, Force, Third Law
Some methanol is poured into a water jug, vaporizes, and then is ignited, propelling the jug.
10208
Syrup Marbles
Mechanics
Mechanics, Force, Buoyancy
Marbles are dropped in syrup and quickly reach a terminal velocity or float. We use this to demonstrate both buoyancy and drag forces.
10209
Third Law carts
Mechanics
Mechanics, Force, Third Law, Cart
Two carts with force meters collide with each other, showing equal and opposite force vs time measurements.
10210
Tension Force Vectors
Mechanics
Mechanics, Force, Tension, Vectors, Equilibrium
A weight is hung on a string tied to two separate force meters. By changing the positions of the meters and the weight, the forces balance differently.
10211
Hammer Pound
Mechanics
Mechanics, Inertia, First Law
A weight is placed on someone's hand and then pounded with a hammer. The hand remains undamaged.
10301
Centripetal Acceleration vs Gravity
Mechanics
Mechanics, Centripetal Force, Gravity, Acceleration
A ball and a weight are tied to opposite ends of a string, the string goes through a tube; holding the tube and swinging the ball around in a circle, you can lift the mass up with centripetal forces.
10302
Ramp Beaker
Mechanics
Mechanics, Gravity, Reference Frames, Acceleration
A beaker full of liquid is rolled down a ramp. The level of the liquid is noted during the moments it is rolling down the slope.
10303
Coriolis Force Puck
Mechanics
Mechanics, Force, Reference Frames, Coriolis
A puck is slid across a rotating reference from. One camera shows the puck sliding in an inertial frame and the other in the frame of the rotating surface.
10304
Swinging beaker
Mechanics
Mechanics, Reference Frames, Acceleration, Pendulum
A beaker filled with water is hung from the ceiling on a platform that stays level. The water level of the beaker swings as the beaker swings.
10305
Pasco Coriolis Bowl
Mechanics
Mechanics, Force, Reference Frames, Coriolis
A small bowl with a water spout is filled with water and water is sprayed from the nozzle back into the bowl.
10306
Loop de Loop
Mechanics
Mechanics, Gravity, Centripetal Force, Acceleration
A marble is rolled down a ramp and made to go through a vertical loop. The precise height to roll it from to complete the loop can be calculated.
10307
Swing the bucket
Mechanics
Mechanics, Gravity, Centripetal Force, Acceleration
Show that by filling a bucket with water and swinging it, the water can be retained even when the bucket is upside-down due to centripetal acceleration or centrifugal force.
10401
Conservation of 2D momentum on an air table
Mechanics
Mechanics, Conservation Of Momentum, Momentum, Air Table
2 pucks collide head on on an air table. One puck stops while the other continues with the velocity of the first. If they collide off-center, the angle their trajectories make is 90 degrees.
10402
Conservation of Momentum on an air track
Mechanics
Mechanics, Momentum, Conservation Of Momentum, Air Track
2 gliders collide on an air track. The first glider stops while the second continues with the velocity of the first.
10403
Bowling Ball Pendulum
Mechanics
Mechanics, Pendulum, Conservation Of Energy
Bowling ball hung from the ceiling is allowed to swing across the room without hurting the demonstrator.
10404
Blasting Cap Gliders
Mechanics
Mechanics, Air Track, Conservation Of Momentum
A small explosive cap is place in between 2 air track gliders and sealed air tight; electric charge detonates the explosive and the carts are driven apart.
10405
Conservation of Energy Pendulum
Mechanics
Mechanics, Pendulum, Conservation Of Energy
A pendulum with a rod blocking its string partway; the ball is swung and despite the string changing lengths halfway through the swing, it achieves the same final height.
10406
Newton's Cradle
Mechanics
Mechanics, Conservation Of Momentum
A Newton's Cradle demonstrated elastic collisions.
10407
Vertical Spring Launcher
Mechanics
Mechanics, Conservation Of Energy, Gravity
A spring-loaded launcher shoots marbles straight up. It is noted a light plastic marble is launched higher than a heavy steel marble.
10408
Conservation of Momentum in Bouncy Balls
Mechanics
Mechanics, Conservation Of Momentum
A small elastic ball and larger elastic ball are dropped. if the small ball is placed on top of the larger ball and dropped, the smaller ball is given much energy from the collision.
10501
Air Table Corkscrew
Mechanics
Mechanics, Air Table, Conservation Of Momentum
A puck is left to spin down a corkscrew on an air table. The corkscrew spins in the opposite direction until the puck lands, at which point they both stop.
10502
Rigid Body Collisions
Mechanics
Mechanics, Conservation Of Momentum, Air Table
A puck collides with another object on the air table. The second object has a dot at its center of mass, and we can see after the collision, the center of mass travels in a straight line, even if the object was hit off-center and rotates. We can also see how its spin is affected by the location of the collision.
10503
Ballerina Moment of Inertia
Mechanics
Mechanics, Moment Of Inertia, Conservation Of Momentum
A person sits/stands on a turntable and begins spinning. By holding weights in or out they can speed up or slow down.
10504
Bike Wheel Ballerina
Mechanics
Mechanics, Conservation Of Momentum
Bike wheel is spun up and demonstrator sits/stands on turntable. By turning the bike wheel they can spin and reorient themselves on the turntable.
10505
Irregular Mass toss
Mechanics
Mechanics, Center Of Mass
A flat, irregularly shaped chunk of foam has its center of mass marked and it is tossed in the air. It rotates about the marked center of mass.
10506
Moment of Inertia display
Mechanics
Mechanics, Display, Moment Of Inertia
Displaying various shapes to understand how they related to moment of inertia.
10601
Rotational Instability with the Intermediate Axis Theorem
Mechanics
Mechanics, Moment Of Inertia
A book is tied shut and tossed into the air. By spinning the book along each of its axes, it is shown that rotation is table along two and unstable along the third. See also Polhode.
10602
Moment of Inertia Ramp Race
Mechanics
Mechanics, Moment Of Inertia
Variety of cylinders and balls are rolled down a ramp, demonstrating the effects of various moments of inertia.
10603
Compound Pendulum
Mechanics
Mechanics, Pendulum, Moment Of Inertia
A hanging bar (a meter stick) is compared to a simple pendulum based on frequency. The equivalent simple pendulum is calculated
10604
Maxwell's Yo-yo
Mechanics
Mechanics, Conservation Of Momentum
A flywheel and axle are wound up and allowed to spin down. The kinetic energy causes it to wind itself back up once it reaches the bottom of the string.
10605
Simple Harmonic Oscillator and Circular Motion
Mechanics, Waves
Mechanics, Waves, Simple Harmonic Oscillation
A rotating pin is shown through a slit from the side and from above, showing the relationship between SHO motion and circular motion.
10607
Walking the Spool
Mechanics
Mechanics, Torque, Equilibrium
The string/ribbon on large metal yo-yo is pulled at an angle, until torque from friction balances out torque from the string.
10608
Oscillating Spring Force
Mechanics
Mechanics, Force, Spring, Frequency, Simple Harmonic Oscillation
A weight on a spring oscillates while hanging from a force meter. The force measurements are recorded on a computer.
10609
Rigid Rotor Rotating Imbalance
Mechanics
Mechanics, Moment Of Inertia
A Bar with diagonally attached weights is technically balanced along each axis, but because of the off-diagonal product of inertia, it wobbles when rotating.
10701
Damped Air Track Glider
Mechanics
Mechanics, Air Track, Damped Oscillator
Air track glider with magnet on it is oscillated by a damping aluminum bar.
10702
Horizontal driven pendulum
Mechanics
Mechanics, Pendulum, Driven Oscillation, Resonance
A pendulum driven by oscillating its pivot point horizontally.
10703
Shattering Wine Glass
Mechanics
Mechanics, Resonance, Frequency, Driven Oscillation
A wine glass is shattered using sound waves from a directional speaker.
10704
Vertical driven pendulum
Mechanics
Mechanics, Pendulum, Driven Oscillation, Resonance
A pendulum driven by oscillating its pivot point vertically.
10705
Kapitza's Pendulum
Mechanics
Mechanics, Pendulum, Driven Oscillation, Equilibrium
A rigid pendulum is driven vertically. With large enough amplitude and frequency, it balances upright.
10801
Apple Drop
Mechanics
Mechanics, Gravity
An apple is dropped from the ceiling in a quick humorous nod to Newton.
10901
Venturi Tube
Mechanics
Mechanics, Fluid
3-section Bernoulli Blower. PVC Pipe with alternating large and small sections with holes in them has air run through it to levitate balls; with some skill, the balls can also be landed again.
10902
Coanda Effect
Mechanics
Mechanics, Fluid
Bernoulli's principle is used to levitate objects (primarily balls) with high speed air currents.
10903
Buoyancy
Mechanics
Mechanics, Fluid, Buoyancy
Weights are lowered into water/corn syrup and change in weight is observed.
10904
Helium balloon
Mechanics
Mechanics, Fluid, Buoyancy
Demonstrating buoyancy by floating a helium balloon.
10905
Torricelli Water Spouts
Mechanics
Mechanics, Fluid
A bottle has some holes poked in it in a vertical series. The bottle is filled with water and it is noted that water pouring out the lower holes sprays out further.
10907
Cartesian Diver
Mechanics
Mechanics, Fluid, Buoyancy
A small vial of air is floated in a closed bottle of water. By squeezing the bottle and increasing the pressure, the vial can be driven down.
10908
Fluid Rotation
Mechanics
Mechanics, Fluid
A Beaker of fluid is rotated on a platform.
10909
Lava Lamp
Mechanics
Mechanics, Buoyancy, Thermal Expansion
The fluid in a lava lamp rises and falls based on its density, a function of temperature.
10910
Poly Density Bottle
Mechanics
Mechanics, Fluid, Equilibrium
A bottle filled with beads and fluids is shaken and exhibits strange buoyancy behavior.
10911
Galileo Thermometer
Mechanics
Mechanics, Buoyancy, Thermal Expansion
A series of bobs of varying densities sit inside a container of fluid. The fluid's density is temperature-dependent, so the temperature of the room can be read based on which bobs float and which sink.
11001
Bike Wheel Precession
Mechanics
Mechanics, Angular Momentum, Gyroscope
Bike wheel is spun up and hung from one side. As it spins down, it precesses.
11002
Pasco Demo Gyro
Mechanics
Mechanics, Angular Momentum, Gyroscope
A large gyroscope used to demonstrate precession and nutation.
11003
Precision Gyro
Mechanics
Mechanics, Angular Momentum, Gyroscope
A high end gyroscope is spun in a variety of configurations to show conservation of angular momentum, precession, etc.
11004
Three Axis Gimbal Gyroscope
Mechanics
Mechanics, Angular Momentum, Gyroscope
A Gyroscope on a 3-axis gimbal maintains its orientation as the mount is spun.
11005
Bike Wheel from Ceiling
Mechanics
Mechanics, Angular Momentum, Gyroscope
As Bike Wheel Precession, but hanging from the ceiling.
11006
Navigational Gyroscope
Mechanics
Mechanics, Angular Momentum, Gyroscope
A 3-axis gimbal gyroscope with electrodes on its frame is spun up. The angles of displacemtn are measured as the gyroscope is rotated.
11007
Gyro in a box
Mechanics
Mechanics, Angular Momentum, Gyroscope
A Gyroscope is spun up in a box and then carried around. It behaves humorously.
11008
Precession
Mechanics
Mechanics, Angular Momentum, Gyroscope
Show the basic wobble of a gyroscope as it tumbles.
11101
Conducting vs Insulating Ball
Electromagnetism
Electricity, Induction
2 balls are hung on springs and interactions with conducting plates are shown; the conducting ball is attracted to a charged plate, it can be charged itself, etc.
11102
Electric Fields in Petri Dish with Rayon and Glycerol
Electromagnetism
Electricity, Electric Field
Electrodes in a petri dish are charged with the Wimshurst generator, the glycerol filled with rayon fibers is poured into the dish. A projector projects the image of the electric field formed shown by the rayon fibers.
11103
Electrophorus, Electroscope, and the Triboelectric Effect
Electromagnetism
Electricity, Induction
An acrylic sheet is electrically charged with rabbit fur, charge is transferred on an aluminum disk, the disk is held to an electroscope and charge is observed.
11104
Franklin Storm Detector
Electromagnetism
Electricity, Induction
Conductive ball is hung between two aluminum plates. When one plate is charged, it attracts the ball, charges it, repels it, and the ball rings between the two plates.
11105
Kelvin Water Dropper
Electromagnetism
Electricity, Induction
Water is dripped into metal cans, and eventually a large voltage exists between the two (A high voltage meter can record this, it can be shown by discharging a discharge lamp across them).
11106
Michelson Interferometer
Waves
Waves, Interference
Demonstration of a michelson interferometer.
11107
Screwdriver Capacitor sparks
Electromagnetism
Electricity, Voltage
A high voltage capacitor is charged to 2kV and discharged with a large screwdriver.
11108
Wimshurst Machine
Electromagnetism
Electricity, Induction, Voltage
A novelty high-voltage electric generator that can create sparks, high voltages, and high electric fields.
11109
Electric Field Effect on a Cathode Ray Tube
Electromagnetism
Electricity, Cathode Ray Tube, Electric Field
Holding statically charged objects up to an analog oscilloscope to show their effect on the electron beam.
11110
Water and Wax Charge
Physics
Running Water over parafin wax leads to the water gaining a high voltage charge.
11201
Cathode Ray Tube Display
Electromagnetism
Electricity, Display, Cathode Ray Tube
Display of Cathode Ray Tube.
11202
Cathode Ray Tube Operation
Electromagnetism
Electricity, Cathode Ray Tube
Showing effect of input voltage on beam position in CRT.
11203
Faraday Cage AM Radio
Electromagnetism
Electricity, Faraday Cage
AM Radio is placed in Faraday cage and receives reduced signal.
11204
Faraday Cage
Electromagnetism
Electricity, Faraday Cage
Electroscope is placed in Faraday cage and when electrophorus is held close to it, no charge is shown. AM Radio is placed in Faraday cage and receives reduced signal.
11205
Faraday Ice Pail
Electromagnetism
Electricity, Gauss's Law
Electroscope is placed inside a metal paint can, electrophorus is held near it to show no measured electric field.
11206
Tape and String Repulsion
Electromagnetism
Electricity, Induction
Scotch tape is attached to strings and pulled from other pieces of scotch tape. If this is done twice, the 2 resulting pieces of scotch tape on strings will repel each other.
11207
Van de Graaff Generator
Electromagnetism
Electricity, Van De Graaff
Running a Van de Graaff generator, showing it sparking.
11208
Van de Graaff Wig
Electromagnetism
Electricity, Van De Graaff
A Wig is placed on a Van de Graaff and its hair raises up when it is run.
11301
Conductivity of Molten Glass
Electromagnetism
Electricity, Resistance
Small glass tube is used to complete a circuit and light a lamp. The lamp does not light until the glass in melted with a blowtorch and becomes conductive.
11302
Exploding Resistor
Electromagnetism
Electricity, Resistance
High voltage detonates a resistor.
11303
Lamp Curve Tracer
Electromagnetism
Electricity, Resistance
An IV curve tracer traces the IV curve of a lamp. It can be noted that resistance goes up as the lamp gets hotter.
11304
Meissner Effect
Electromagnetism
Magnetism, Electricity, Magnetic Field, Superconductivity
A superconductor is floated over some magnets.
11305
Resistor Assortment
Electromagnetism
Electricity, Resistance
Displaying a variety of resistors.
11306
Superconductor
Electromagnetism
Magnetism, Electricity, Magnetic Field, Superconductivity
A superconductor is dipped in LN2, and its resistance is shown to plummet as it reaches its critical temperature.
11307
Resistive Heater
Electromagnetism
Electricity, Resistance
A wire is heated by a current. The wire will glow, demonstrating blackbody radiation. The temperature increase can also be measured to demonstrate ohmic heating.
11308
Conductivity in Melting Ice
Electromagnetism
Electricity, Resistance
Ice is used as a resistor in a circuit with a light bulb. The bulb does not light until the ice melts.
11401
2 Potentiometer Voltage Divider
Electromagnetism
Electricity, Potentiometer, Voltage
Lighting a lamp with a potentiometer voltage divider circuit; 2 different value pots are used to demonstrate the effects of the resistance of the divider vs the resistance of the lamp.
11402
Internal Resistance for Car Battery and AAs
Electromagnetism
Electricity, Voltage, Resistance, Current
Showing 12V pack of AA batteries and 12V car battery powering the same lamp, showing different internal resistances.
11403
Diode Rectifier
Electromagnetism
Electricity, Voltage, Diode
Sine wave sent through diode to show only positive sections on oscilloscope. The signal can be converted from AC to DC.
11404
Extension Cord Voltage Divider
Electromagnetism
Electricity, Voltage, Voltage Divider
An extension cord and power strip power a heating coil; voltage is measured at the outlet and at the power strip to show voltage drop across the extension cord.
11405
Thevenin Equivalent Circuit
Electromagnetism
Electricity, Voltage
A messy circuit is measured to its Thevenin equivalent.
11406
Wheatstone Bridge
Electromagnetism
Electricity, Resistance, Voltage
A wheatstone bridge is used to calculate resistance.
11501
Field Emission Microscope
Electromagnetism
Electricity
Demonstration of FEM with HV power supply.
11502
Jacob's Ladder
Electromagnetism
Electricity, AC Voltage
Very high AC voltage drives current between 2 antennae.
11503
Milikan Chamber
Electromagnetism
Electricity, Charge, Electron
Displaying the construction of the Millikan Oil drop chamber.
11504
Tesla Coil
Electromagnetism
Electricity, Voltage, AC Voltage
A tesla coil.
11505
Electric Whirl
Electromagnetism
Electricity, Charge, Van De Graaff
A small spinner with pins on it is held near the Van de Graaff. Electrons ejected from the pins cause the spinner to spin.
11506
Van de Graaff Lightning Chamber
Electromagnetism
Electricity, Voltage, Van De Graaff
A small chamber with spikes is held between the high and low of the Van de Graaff. Sparks can be seen running inside the chamber.
11507
Lemon Battery
Electromagnetism
Electricity, Voltage
A series of citrus fruit or electrolytic foods are set up to light an LED.
11508
Electrical Treeing and Lichtenberg Figures
Electromagnetism
Electricity, Dielectric
A wood surface is dampened with a baking soda water solution, then a high AC voltage is applied across it. Char patterns appear in the wood between electrodes.
11509
Van de Graaff Racer Ball
Electromagnetism
Electricity, Charge, Van De Graaff
A ball is rolled between two metal plates, propelled by electrostatic forces from a Van de Graaff Generator.
11510
Van de Graaff Confetti
Electromagnetism
Electricity, Charge, Van De Graaff
A person charges themself with a Van de Graaff and holds their hand over some confetti. The confetti flitters around under the hand.
11601
10F Capacitor Discharging Through Lamp
Electromagnetism
Electricity, Capacitor
Charging a 10F capacitor and discharging it through a lamp shows how much energy is stored, as well as charge and discharge time of high-capacitance capacitors.
11602
Capacitor Assortment
Electromagnetism
Electricity, Capacitor, Display
Display of various capacitors.
11603
Exploding Capacitor
Electromagnetism
Electricity, Capacitor
High voltage detonates a capacitor.
11604
Kerosene Capacitor
Electromagnetism
Electricity, Capacitor, High Voltage
A capacitor with 2 small tabs that reach into a small jar partially filled with kerosene. When a high voltage is applied to the capacitor, the kerosene creeps up to fill the space in between the tabs.
11605
LCR Circuit
Electromagnetism
Electricity, LCR
Showing the relationships of the voltages across each element of an LCR circuit for various L,C, R, and frequency.
11606
Parallel Plate Capacitor with Dielectrics
Electromagnetism
Electricity, Capacitor, Dielectric
Voltage is measured across a parallel plate capacitor. If a dielectric is introduced, the voltage goes down.
11607
Parallel Plate Capacitor with Variable Distance
Electromagnetism
Electricity, Capacitor
Measuring the voltage on a parallel plate capacitor as the distance between the plates varies.
11608
DC RC Circuit
Electromagnetism
Electricity, Capacitor
Basic behavior of an RC DC circuit.
11609
Series and Parallel Capacitance
Electromagnetism
Electricity, Capacitor
Capacitance of capacitors in series vs parallel.
11701
Cross Product Water Whirl Tub
Vectors
Water is spiral drained in a large tub. Pucks with markings on them can rotate when floated on the spiraling water.
11702
Jumping Wire
Electromagnetism
Magnetism, Electricity, Current, Magnetic Field, Lorentz Force
A wire is drooped into a strong magnetic field, and when the wire is connected to a car battery, the current makes the wire jump.
11703
Magnets and Compasses
Electromagnetism
Magnetism, Magnetic Field
Having a magnet show the deflection of a single compass, and having several compasses show the overall magnetic field.
11704
Piezo Sparker
Electromagnetism
Electricity, Capacitor, Piezoelectricity
Dielectric breakdown from high voltage in a piezo sparker is shown.
11705
Parallel Plate Capacitor with Metal Plate
Electromagnetism
Electricity, Capacitor
A parallel plate capacitor has another metal plate put in between its two plates, simulating 2 capacitors in series.
11706
Magnet and Paperclips
Electromagnetism
Magnetism, Magnetic Field
Paperclips are tied onto the ends of strings and suspended in the air by a magnet.
11707
Earnshaw Tower
Electromagnetism
Magnetism, Magnetic Field
Stacking several disc magnets so they float above each other.
11708
Pencil Levitator
Electromagnetism
Magnetism, Magnetic Field, Equilibrium
A pencil with magnets is levitated.
11709
Electron Mass to Charge Ratio in Teltron Tube
Electromagnetism
Magnetism, Magnetic Field, Electricity, Charge, Lorentz Force
An electron beam is fired in a Teltron tube and arced by a Helmholtz coil. The q/m ratio can be calculated.
11801
Barlow Generator
Electromagnetism
Magnetism, Generator
A metallic wheel completes a current path; By spinning the wheel in a magnetic field, a voltage is induced.
11802
Barlow Motor
Electromagnetism
Magnetism, Motor, Lorentz Force
A metallic wheel completes a current path. By powering the circuit in a magnetic field, the wheel spins.
11803
Brushed DC Motor
Electromagnetism
Magnetism, Motor, Lorentz Force
A wire loop in a magnetic field is rotated with brush-commutator connection to DC Power supply.
11804
Hall Effect
Electromagnetism
Magnetism, Magnetic Field, Lorentz Force
Demonstrating the Hall effect with a basic Hall Effect sensor.
11805
Mendocino Motor
Electromagnetism
Magnetism, Motor, Electromagnet
A floating spinner with solar panels on it spins when light is shown on it.
11806
Three Phase Motor
Electromagnetism
Magnetism, Motor
A metal can is placed over 3 inductors and spun with 3-phase power.
11807
Three Phase Levitator
Electromagnetism
Magnetism, Motor, Equilibrium
A metal plate is levitated using a 3-phase power supply.
11809
Synchronous AC Motor
Electromagnetism
Magnetism, Motor
An AC signal spins a coild of wire through a magnetic field.
11810
Motor Cross Section Display
Electromagnetism
Magnetism, Motor, Display
Display a cut-open motor.
11811
Homopolar Motor
Electromagnetism
Magnetism, Motor
A simple motor is constructed from a wire, a battery, and a magnet. Different geometry can also incorporated a screw.
11812
Gauss Cannon
Electromagnetism
Magnetism
A series of ferromagnetic bearings are lined up with a magnet. An additional bearing is rolled into them, dislodging one at the opposite end.
11901
Copper Resistivity vs Temperature
Electromagnetism
Electricity, Resistance
A spool of copper wire is dipped into LN2 and its resistivity lowers with temperature.
11902
Iron Filing Suspension Jar in Magnetic Field
Electromagnetism
Magnetism, Magnetic Field
Magnetic field lines are shown in 3 dimensions with a container of iron filings in oil.
11903
Magnetic Field of a Line Current
Electromagnetism
Magnetism, Magnetic Field, Current
Compasses or iron filings demonstrate the magnetic field around a line of current.
11904
Electromagnet Effect on a Permanent Magnet
Electromagnetism
Magnetism, Electromagnet
An electromagnet is powered to twist and turn a permanent magnet.
12001
Diode LED and Photodiode Curves
Electromagnetism
Electricity, Diode
IV Curves for LED and photodiode on a Curve Tracer.
12101
Bar Magnet in Wire Loop
Electromagnetism
Magnetism, Magnetic Field, Faraday's Law, Lenz's Law
Faraday's law demonstrated by moving a magnet through a wire loop and showing the resulting voltage form.
12102
Curie Point of Gadolinium
Electromagnetism
Magnetism, Paramagnetism
Low temperature ferromagnetism of gadolinium is demonstrated by dipping a chunk in ice water and letting it hang from a magnet.
12103
Magnet and CRT
Electromagnetism
Magnetism, Cathode Ray Tube, Van De Graaff
A magnet deflects the single dot on an analog oscilloscope.
12104
Magnet on Graphite, Aluminum, LO2
Electromagnetism
Magnetism, Paramagnetism
A magnet is held to these materials to show their magnetic properties. See that Liquid Oxygen is paramagnetic
12105
Magnetic Bubble
Electromagnetism
Magnetism
When a magnet is held to a ferromagnetic garnet, tubular domains reform rapidly, which can be observed through a microscope.
12106
Magnetic Field of Earth
Electromagnetism
Magnetism, Magnetic Field
Measuring the voltage across a rotating loop of wire, one can calculate the magnetic field of the earth.
12201
Copper Pendulum in Electromagnet Field
Electromagnetism
Magnetism, Electromagnet, Lenz's Law
A Copper pendulum swinging through a high magnetic field (from an electromagnet) is damped and stops.
12202
Gaussmeter B Field in a Solenoid
Electromagnetism
Magnetism, Magnetic Field
Using a Gauss meter to measure the B Field at various points in a solenoid.
12203
Hand Crank Light Bulb
Electromagnetism
Magnetism, Generator
Powering a light bulb connected to a hand crank motor.
12204
Magnetic Field of Different Shapes of Current
Electromagnetism
Magnetism, Magnetic Field, Faraday's Law
Solenoid and ring wire configurations are shown on a plastic platform; iron filings are laid around the platform and they trace the magnetic field on the plane, shown on a projector.
12205
Lenz Law Slab
Electromagnetism
Magnetism, Lenz's Law
Swinging a strong magnet into a slab of copper, Lenz's Law stops it before it hits, or damps it if you try to swing it parallel. The magnet also sticks if you move the slab away from the magnet.
12207
Magnet in a Tube
Electromagnetism
Magnetism, Lenz's Law
A magnet is dropped through a copper tube and the extreme slowdown is noted.
12208
Metal Rod Rolling Through B Field
Electromagnetism
Magnetism, Faraday's Law
A metal rod rolls on rails through a high magnetic field. With the rails connected to an oscilloscope, the rod completes the circuit, so a voltage is observed, in addition to the rod slowing down. Aluminum and stainless steel rods were used.
12209
Ring Launcher
Electromagnetism
Magnetism, Lenz's Law
A strong electromagnet launches an aluminum ring when activated.
12210
Railgun
Electromagnetism
Magnetism, Lorentz Force
A conductor is launched from 2 rails using the Lorentz Force.
12301
2 Ring Transformer
Electromagnetism
Magnetism, Magnetic Field, Transformer
Frequency generator powers one loop of wire; DSO shows the induced current in a nearby loop of wire.
12302
Electromagnet Backfire
Electromagnetism
Magnetism, Electromagnet, Inductor
Running an electromagnet with knife switch and high current, the opening the knife switch and observe the arcing.
12303
DC LR Circuit
Electromagnetism
Electricity, Magnetism, Inductor
Basic behavior of LR circuit.
12304
Nonconservative E Field from Electromagnet
Electromagnetism
Magnetism, Magnetic Field
It is shown that the induced voltage recorded on a wire from an AC electromagnet depends on the wire geometry.
12305
Wire Loop DC generator
Electromagnetism
Magnetism, Generator
A wire loop held in a magnetic field is spun around at a constant angular velocity to create an voltage.
12401
Basic Transformer
Electromagnetism
Magnetism, Transformer
Demonstrating the voltage transformation in a commercial transformer.
12402
Changing Magnetic Flux Between Solenoid and Wire Loop
Electromagnetism
Magnetism, Magnetic Field
Recording the voltage output of a wire loop, the loop is moved past a solenoid, over a solenoid, and the solenoid is moved past the wire, all showing the same effect.
12403
Inductive Sensor Metal Detector
Electromagnetism
Magnetism, Inductor, LCR
Setting a up a circuit with a large inductor loop that rings when the induction changes, then inserting pieces of metal and other materials into the loop. Look up Colpitts Oscillator.
12404
Electrical Filters
Electromagnetism, Waves
Magnetism, LCR, Waves
Showing the basic behaviors of LR and RC circuits as High-Pass and Low-pass filters, and differentiators and integrators.
12501
Displacement Current
Electromagnetism
Magnetism, Current
Sine wave sent to 2 large disks with a large Rogowski coil between them, showing the current waveform is the same as long as the circuit or air gap is contained in the coil.
12502
Microwave Dipole Antenna
Electromagnetism
Polarization, Magnetism, Microwave, Dipole
A microwave dipole antenna emits an AM broad, which is picked up by a separate antenna. The signal has the microwave frequency filtered out and the modulated frequency is played over the speakers. The volume clearly goes down the further from the antenna one goes, and by twisting the receiver, the polarization is observed.
12503
Crookes Radiometer, Fake Solar Sail
Electromagnetism
Magnetism, Light
A fake version of a solar sail-- in a seal clear jar are black and white sails on a spindle. When light is shown on the black sails, the air around them heats up and expands, spinning the sail. The demo looks like a solar sail.
12504
Speed of Light
Electromagnetism, Waves
Magnetism, Waves, Light
A laser is bounced across the room and the delay is recorded to calculate the speed of light.
12601
Electrical Pulse in a Long Cable
Electromagnetism, Waves
Magnetism, Waves, Light
A pulse is sent through a length of cable; time of travel, as well as reflection are observed with open end, shorted end, and 50Ω termination.
12602
LCR Parallel Circuit
Electromagnetism
Magnetism, LCR
Showing the relationship between current and frequency in a parallel LCR circuit.
12603
Transmission Line
Electromagnetism, Waves
Magnetism, Waves
Long series of capacitors and inductors imitate a transmission line; wave signals are sent down the line and signal delay is measured across the distance.
12702
The Arago Spot
Waves
Waves, Light, Diffraction
Laser shines on a marble, a distant screen shows a circular diffraction pattern, with a bright spot in the center due to Fresnel Diffraction.
12703
Laser Diffraction Grating
Waves
Waves, Light, Diffraction
Laser shown through diffraction grating.
12704
Microwave Dipole Standing Wave
Electromagnetism
Polarization, Magnetism, Microwave, Dipole
Two microwave dipole antennae are set up about a meter apart. A receiver antenna picks up the signal between them. The signal goes through nodes and antinodes and is still polarized.
12705
Microwave Resonance Chamber
Electromagnetism
Magnetism, Microwave
Microwave signal is sent into a resonance chamber and picked up on the end and sent to a speaker. The volume goes up at specific frequencies and can be attenuated by placing metal pins into the chamber.
12706
Shive Wave Machine
Waves
Waves
A wire with a series of rods is twisted, creating a visible pulse. The pulses can be observed travelling across the device.
12707
Single Slit Diffraction and Double Slit Diffraction
Waves
Waves, Light, Diffraction
Laser in single slit diffraction. Laser in double slit diffraction.
12708
Static Electric Water Deflection
Electromagnetism
Electricity
A charged surface is held near a stream of water, deflecting it.
12901
Dipole Magnet Interactions
Electromagnetism
Magnetism
Basic demonstration of bar magnets interacting with each other.
12902
Ferromagnetism
Electromagnetism
Magnetism, Ferromagnetism
Demonstrating Ferromagnetism by inducing a magnetic field in some nails.
13001
Can Crusher
Electromagnetism
Magnetism, Lenz's Law
Large capacitor is charged to high voltage, discharged through loop of wire, and soda can in the loop of wire is crushed by EM forces.
13002
Barkhausen Effect of Magnetic Domains in Speaker
Electromagnetism
Magnetism, Magnetic Field, Barkhausen
Hooking up an inductor with a steel core to a speaker, you can hear crackling when you bring a magnet near it.
20101
Air Track Oscillator
Waves
Waves, Air Track, Simple Harmonic Oscillation
Simple Harmonic Motion demonstration with an air track glider on springs.
20102
LCR Pulser
Waves
Waves, Damped
Sending a low-frequency square wave into an LCR circuit and watching the ringdown behavior of the components.
20103
Tuning Fork Signal
Waves
Waves, Tuning Fork, Damped
Tuning fork signal is picked up by a microphone and shown on an oscilloscope.
20104
U-Tube Water Oscillator
Waves
Waves, Damped
A U-tube is partially filled with water, which is raised on one side and plugged up. When the tube is upright, releasing the plug causes the water to oscillate back and forth.
20105
Blackbody Absorber
Waves
Waves, Blackbody
A Stack of Razor Blades that absorbes radiation.
20106
Coefficient of Restitution
Restitution, Oscillation
A small marble is dropped on a concave metal surface. The surface outputs a coax signal that can be tracked on an oscilloscope or played on a speaker.
20201
Two Coupled Tennis Balls
Waves
Waves, Coupled Oscillation
2 tennis balls on flexible slats connected by a spring. Coupling strength can be changed by moving the spring.
20202
Double Bar Chaotic Pendulum
Waves
Waves, Coupled Oscillation, Pendulum, Chaos
A bar hanging from a bar, forming a double pendulum.
20203
Frequency Generator beats
Waves
Waves, Interference
Connecting 2 signal generators in series to a speaker and listening to the beats.
20204
Double Ball Pendulum
Waves
Waves, Pendulum, Coupled Oscillation
A basic ball pendulum hangs off another ball pendulum. Swinging these results in couple oscillations.
20205
Tuning Fork Beats
Waves
Waves, Tuning Fork, Interference
Two tuning forks beat against each other.
20206
Driven Spring
Waves
Waves, Driven Oscillation
A weight on a spring is driven by a linear actuator, driving slow, fast, and at resonance.
20207
Metronome Synchronoization
Waves
Waves, Driven Oscillation, Coupled Oscillation
Several metronomes are placed on a mobile platform and started out of sync. Over time, as they transfer energy, they synchronize their beats
20301
Two Coupled Air Track gliders
Waves
Waves, Air Track, Coupled Oscillation
2 air track gliders connected by springs. Resonant frequencies can be found.
20302
Two Coupled Bowling Ball Pendula
Waves
Waves, Coupled Oscillation, Pendulum
2 bowling ball pendulum connected by springs. Resonant frequencies can be found.
20303
Wilberforce Pendulum
Waves
Waves, Pendulum, Coupled Oscillation
A weight on a spring with a weighted rod sticking through it is stretched and released. Energy is transferred between vertical oscillation and rotational oscillation.
20304
Driven Air Track Glider
Waves
Waves, Air Track, Driven Oscillation, Resonance
Glider with springs on Air Track is driven by a motor.
20305
Coupled LC Circuit
Waves
Waves, Coupled Oscillation, Inductor, Capacitor
Two LC circuits are put in parallel and the waveform is analyzed
20401
Three Coupled Air Track Gliders
Waves
Waves, Air Track, Coupled Oscillation
3 air track gliders connected by springs. Resonant frequencies can be found.
20402
Six Coupled Bowling Ball Pendula
Waves
Waves, Pendulum, Coupled Oscillation
Six bowling ball pendula are connected by springs and driven by a piston motor. Up to 6 normal modes can be found.
20403
Sine Wave String
Waves
Waves, Normal Modes
A string is pulled tight over a pulley with a weight. The string is vibrated by an oscillator, and dozens of normal modes can be found.
20501
Long Spring Pulse
Waves
Waves, Transmission And Reflection
A long spring is strung up across the room. It is plucked and its pulses are seen traveling along its length.
20601
Chladni Plate with Bow
Waves
Sound, Waves, Normal Modes
Sand is poured onto a plate and the a cello bow is rubbed across the plate, causing it to vibrate, and the sand shows the shape of the various normal modes.
20602
Recorder
Waves
Sound, Waves, Normal Modes
Using a recorder (the musical instrument) to talk about sound waves.
20603
Slide Whistle
Waves
Sound, Waves, Normal Modes
A slide whistle is played, noting the change in tone as it is lengthened and shortened.
20604
Small Chladni Plate with Oscillator
Waves
Sound, Waves, Normal Modes
Sand is put on a chladni plate, the plate is stimulated by an oscillator, forming complex patterns.
20605
Resonance Tube
Waves
Waves, Normal Modes, Sound
A large vertical tube is filled with water and an open-ended tube is lowered into it. A speaker plays a frequency into the open-ended tube. By changing the frequency or how much of the tube is in the water, the sound can become louder and the wavelength and speed of sound can be determined.
20606
Standing Wave Resonance Wire Loop
Waves
Waves, Normal Modes
A circular loop of wire is vibrated and normal modes can be observed at various frequencies.
20607
Wave Machine Standing Waves
Waves
Waves, Normal Modes
Standing waves can be established on a Shive wave machine.
20608
Rubens' Tube
Waves
Waves, Normal Modes, Sound, Fire
A series of holes in a tube are set on fire and sound waves are played into the tube, affecting the flame heights across the tube.
20609
Wiggling Rope
Waves
Waves, Normal Modes
By shaking a rope by hand, standing waves can be established
20611
Acoustic Levitation
Waves
Sound, Waves, Normal Modes, Equilibrium
Speakers, or acoustic transducers, directed upward will levitate small items. This is similar to a vertical Chladni Plate.
20701
Boundary Conditions on Wave Machine
Waves
Waves, Transmission And Reflection
Wave reflection is demonstration with open, closed, and damped boundary on Shive Wave Machine.
20702
Transmission and Reflection Through Different Media (Long Spring)
Waves
Waves, Transmission And Reflection
2 different long rubber tubes are tied together and strung across the room. One side is plucked and the wave behavior at the boundary between the two is observed.
20703
Transmission and Reflection Through Different Media (Wave Machine)
Waves
Waves, Transmission And Reflection
2 Shive Wave machines with different sized bars and hooked together and the behavior at the boundary is observed.
20704
Refraction, Transmission, and Reflection with Tabletop Laser Box
Waves
Refraction, Waves, Transmission And Reflection
A laser is shone on a plastic lens and the resulting behavior at the boundary is observed.
20705
Coupled Tuning Forks
Waves
Waves, Tuning Fork, Coupled Oscillation
One tuning fork drives another tuning fork of the same frequency. A ping pong ball may be hung against the second tuning fork so that its vibrations can be more easily seen.
20706
Quarter-Wave Plate
Waves
Light, Waves, Waveplate, Polarization
Behavior of a quarter waveplate is demonstrated: circularly polarizing light and linearly polarizing light based on orientation.
20707
Dispersion in a prism
Waves
Waves, Dispersion
White light is shone through a prism, and the resulting rainbow pattern is displayed
20801
Cylinder with Reflective Film
Waves
Waves, Transmission And Reflection
A cylinder with a dielectric film which reflects different colors depending on the angle of light incident upon it.
20802
Diffraction (Overhead Projector)
Waves
Waves, Diffraction, Light
Diffraction grating is laid on overhead projector and the pattern is projected on a screen or wall.
20803
Wave Interference in Ripple Tank
Waves
Waves, Interference
Water is put into a clear drum, and the surface is beaten with 2 oscillators; Light is shown through the surface to see the waves form and interfere.
21001
Polarized Filters
Waves
Waves, Light, Polarization
Polarized lenses are demonstrated, linearly polarizing light and showing the effect of orientation of a second lens.
21002
Dispersion on a Steel Wire
Waves
Waves, Dispersion
A steel wire is suspended over the room ad plucked. An audible disperson can be heard, as well as seen on an oscilloscope.
21201
CE Thomson / Davisson Germer
Waves, Quantum
Quantum, Waves, Diffraction
Electron beam in CRT is diffracted off a surface, with resultant beams illuminating a screen at points showing the atomic structure.
21202
Psi Box
Quantum
Quantum
Dice and cats used to talk about the random effects of quantum mechanics.
21301
Franck Hertz
Quantum
Quantum
DSO displays current vs voltage of Franck Hertz apparatus.
21401
Tunneling Ball Uphill
Quantum
Quantum
A ball is rolled uphill and over a bump to demonstrate the concept of tunneling.
21501
Frustrated Internal Reflection (Visible)
Waves, Quantum
Waves, Quantum, Transmission And Reflection, Light
Starting with a laser undergoing total internal reflection in a plastic medium, introduce another piece of plastic at one of the reflection points and observe some of the laser transmitted into the new piece of plastic.
21502
Ramsauer Townsend
Quantum
Quantum
An electron beam is fired into a noble gas and collected on the far side. Resulting current is plotted against voltage, and a dip appears at ionization energy.
21503
Frustrated Internal Reflection (Microwave)
Waves, Quantum
Quantum, Microwave, Waves, Transmission And Reflection
Two wax blocks are placed together and microwaves are sent through them, showing frustrated total internal reflection between them.
21801
Spectral Lines
Quantum
Quantum, Ionization, Light
Shining a gas lamp into a spectrometer to observe the spectral lines.
21802
Black Fire
Quantum
Quantum, Ionization, Fire
Salt is burned while illuminated by a sodium lamp. The sodium ions absorb the light from the sodium lamp, the flames appear black.
22001
Identical and Non-Identical Billiard Particles
Quantum
Quantum
Using cue balls and 8-balls to demonstrate the difference between identical and non identical particles.
22002
Dirac Glass Orientation
Quantum
Quantum
A wine glass is filled with water and twisted around one's body while maintaining its upright orientation.
22301
Air Table Diffusion
Mechanics, Statistical Mechanics
Statistical Mechanics, Air Table, Diffusion, Equilibrium
Several pucks are placed in two pens on an air table; the walls oscillate to introduce motion and the diffusion of the pucks across the pens is observed.
22302
Laminar Flow in Couette Cell
Mechanics, Statistical Mechanics
Statistical Mechanics, Laminar Flow, Fluid
Food dye is injected into a cylindrical spinner filled with corn syrup. The spinner is spun to distort the dyed areas, then spun back to restore them.
22303
Adjustable Slant Air Table
Mechanics, Statistical Mechanics
Statistical Mechanics, Air Table, Diffusion
An air table is slanted to demonstrate the effect of a potential field on thermal motion.
22401
Blackbody Boxes
Mechanics, Statistical Mechanics
Statistical Mechanics, Blackbody
3 boxes lined with foil, white paint, dark paint, with a hole in their lids. Light is shone into the hole, but no light comes out.
22402
Blackbody Lamp and Spectrometer
Mechanics, Statistical Mechanics
Statistical Mechanics, Blackbody
Blackbody shines into spectrometer, and its spectrum is shown.
22403
Thermal Radiation
Mechanics, Statistical Mechanics
Statistical Mechanics, Thermal Radiation
Thermal radiation from different materials (including a shiny and a black painted side of the same paint can).
22404
Specific Heat Capacity of Water and Steel
Mechanics, Statistical Mechanics
Statistical Mechanics, Heat Capacity, Thermodynamics
Heating steel and water and comparing the change in temperature of both materials.
22701
Ruchardt Experiment -- Adiabatic Gas Oscillator
Mechanics, Statistical Mechanics
Statistical Mechanics, Adiabatic, Gas Law, Thermodynamics
Gas is fed into a small chamber and its oscillations are measured on DSO; Gamma of the gas can be calculated.
22702
Fire Piston
Mechanics, Statistical Mechanics
Gas Law, Statistical Mechanics, Adiabatic, Fire, Thermodynamics
A small piece of cotton is placed in a clear piston and it is rapidly compressed, igniting it.
22703
Balloons in Liquid Nitrogen
Mechanics, Statistical Mechanics
Statistical Mechanics, Gas Law, Thermodynamics
Balloons deflate when temperature is lowered.
22704
Balloons in Vacuum
Mechanics, Statistical Mechanics
Statistical Mechanics, Gas Law, Thermodynamics
Ballons inflate subjected to a vacuum.
22705
Pasco Ideal Gas Law Sensors
Mechanics, Statistical Mechanics
Statistical Mechanics, Gas Law, Thermodynamics
Pressure, Temperature, and Volume can be related by sensors and measurements of a volume of gas.
22801
Superfluid Helium
Mechanics, Statistical Mechanics
Statistical Mechanics, Superfluid
Liquid helium goes superfluid. We see its surface stop bubbling, fluid creep around a small container, and a fountain effect.
22802
Triple Point of N2
Mechanics, Statistical Mechanics
Statistical Mechanics, Triple Point, Thermodynamics
Liquid nitrogen is placed in a bell jar and it is vacuumed down to the triple point.
22901
Steam Engine
Mechanics, Statistical Mechanics
Statistical Mechanics, Steam Engine, Thermodynamics
A small steam engine is demonstrated.
22902
Stirling Engine and Generator
Mechanics, Statistical Mechanics
Statistical Mechanics, Generator, Stirling Engine, Thermodynamics
A stirling engine is heated to run; the same engine is run manually in reverse, showing that end is cooled in a refrigeration cycle.
22903
Stirling Engine Exploded
Mechanics, Statistical Mechanics
Statistical Mechanics, Stirling Engine, Display, Thermodynamics
A display of the inside of a stirling engine.
22904
Pasco Visible Stirling Engine
Mechanics, Statistical Mechanics
Statistical Mechanics, Stirling Engine, Thermodynamics
A stirling engine with a propeller is sat on a hot plate, which spins the propeller.
22910
Peltier Seebeck Thermoelectric Generator
Thermoelectricity
A device with an Antimony-Bismuth thermocouple has current run through it. The side where current runs from Sb to Bi cools down while the side with Bi to Sb heats up. This can be monitored by enclosing it in an airtight chamber with a water droplet as a gauge.
32401
Tensile Strength of Wire
Tensile Strength
Weights are hung from a thin wire until it stretches and breaks.
32702
Diffraction grating and colored water
Light, Diffraction
Light is shown through colored water and a diffraction grating shows the attenuation of certain colors based on which pigment is in the water.