Refraction of Light
Send a ray from one medium into another and watch it bend.
Projectile Motion
Choose a launch speed and angle, then launch and compare with the formulas.
Simple Pendulum
Change the length, gravity and starting angle, and time the swing.
Spring–Mass Oscillator
Hang any load on a helical spring, pull it down, time the oscillations with a stopwatch and find the force constant and effective mass of the spring from your own readings.
Surface Tension by Capillary Rise
Dip a fine glass tube in a liquid, read the meniscus and the needle tip with a travelling microscope, and work out the surface tension from your own readings.
Newton's Law of Cooling
Let a hot liquid cool in a calorimeter, read the thermometer at fixed intervals and plot the cooling curve. Choose any liquid, any amount, any room, with a fan, a lid or cotton-wool lagging.
Sonometer: Law of Length
Move the bridges until the wire resonates with each tuning fork and show that n × l stays constant. Any fork, any load, any wire.
Sonometer: Law of Tension
Keep one tuning fork, change the load on the hanger and show that T / l² stays constant. Any fork, any load, any wire.
Resonance Tube: Speed of Sound
Lower the water in a resonance tube, hunt for the loud points for each tuning fork, and work out the speed of sound and the end correction from your own readings. Any fork, any temperature, any tube, any gas.
Angle of Contact and the Meniscus
Change the angle of contact and watch the liquid surface in a capillary tube go from concave to flat to convex, and the column rise or fall.
Metre Bridge: Unknown Resistance
Tap the jockey along the wire of a metre bridge to hunt for the null point, then find an unknown resistance from X = R l / (100 − l). Any resistance, any cell, any wire.
Metre Bridge: Series and Parallel Laws
Measure two coils on a metre bridge one at a time, then joined in series and in parallel, and check Xs = X₁ + X₂ and 1/Xp = 1/X₁ + 1/X₂ from your own readings.
Kelvin's Method: Resistance of a Galvanometer
Put the galvanometer itself in one gap of a metre bridge, touch the jockey along the wire and find the point where touching leaves the deflection unchanged. Any galvanometer, any resistance, any cell.
Potentiometer: Potential Drop Along the Wire
Send a steady current through a long uniform wire, touch the jockey at different lengths and read the voltmeter. The potential drop grows in step with the length. Any driver, any rheostat, any wire.
Potentiometer: Comparing Two EMFs
Balance each cell against the fall of potential along the wire, find the null point with the galvanometer and compare the emfs from the two balancing lengths. Individual method, and sum and difference method.
Potentiometer: Internal Resistance of a Cell
Balance a cell on a potentiometer wire, first on open circuit and then while it drives a current through a resistance box, and work out its internal resistance from the two balancing lengths.
p-n Junction Diode Characteristics
Raise the supply step by step, read the voltmeter and the milliammeter, and plot the forward and reverse characteristic of a junction diode. Any diode, any supply, any resistor, any temperature.
Zener Diode Characteristics
Reverse-bias a Zener diode, watch the current stay tiny and then rise sharply at breakdown, and find the breakdown voltage from your own readings. Real parts, an unknown Zener and fully custom values.
Logic Gates
Fit a real logic IC on the trainer board, set the inputs A and B with the switches, watch the output LED and build the truth table of each gate yourself. Then make every gate from NAND or NOR gates alone.
Transistor Characteristics (Common Emitter)
Wire an n-p-n transistor in common-emitter connection, read four meters, and plot its input, output and transfer characteristics. Find the input and output resistance and the current and voltage gains from your own readings. Any transistor, any voltage, any resistor.
Conical Pendulum
Whirl a bob on a string in a horizontal circle so that the string traces out a cone. Change the length, the angle or the speed, see the forces on the bob, time the revolutions with a stopwatch and find out what the period depends on.
Vertical Circular Motion
Give a bob on a string, a bob on a light rod or a toy car on a loop track a push at the bottom and watch it go round a vertical circle, or fail to. See the tension at every point, the string going slack and the bob flying off as a projectile, and find the lowest speed that gets it round.
Banking of Roads
Drive a car round a banked curve of any radius, banking angle and road surface. Watch the friction needed flip from down the slope to up the slope, and see the car skid outwards or slide down when it leaves the safe speed band.
Moment of Inertia Explorer
Choose a ring, disc, sphere, rod, plate or your own point masses, set its mass and size, and pick the axis. A falling mass on a string spins it up: see how a larger moment of inertia turns more slowly, and find I = I_cm + Md² from your own timings.
Rolling Down an Incline
Race a ring, a disc, a solid sphere, a hollow sphere, a sliding block and a body of your own down a slope of any angle, length and roughness. See how the kinetic energy splits between moving along and spinning, when a body rolls and when it slips, and find the finishing order from your own timings.
Viscosity: Stokes' Law and Terminal Velocity
Drop a ball of any size and material into a tall jar of glycerine, castor oil, honey, water or any liquid you like. Watch it speed up until the viscous drag and the upthrust balance its weight, time it between two marks and find the viscosity of the liquid from your own readings.
Equation of Continuity and Bernoulli's Principle
Push water, blood, air or any fluid through a pipe with a narrow throat. Watch the fluid speed up in the narrow part, read the drop in pressure on piezometer tubes or a Venturi meter, and check that P + ½ρv² + ρgh stays the same all along the pipe.
Gas Molecules in a Box
Watch the molecules of a gas fly about in a box with a movable piston. Change the temperature, the volume, the amount and the kind of gas, read the pressure gauge, see the Maxwell spread of speeds, and discover the gas laws from your own readings.
Black Body Radiation Spectrum
Heat a body to any temperature and see its glow and its full spectrum. Watch the peak move (Wien's law), the radiated power grow as T⁴ (Stefan–Boltzmann law), compare curves, and find b and σ from your own readings.
Thermodynamic Processes on a P–V Diagram
Take a gas in a cylinder through isothermal, adiabatic, isobaric, isochoric and polytropic steps, or a whole engine cycle. The piston moves, the P–V curve is traced live, and the work, heat and change in internal energy are shown for every step.
Carnot Engine
A cylinder of gas drives a flywheel through a connecting rod. It is moved from a hot reservoir to an insulating stand to a cold reservoir and back for the four strokes of the Carnot cycle, while the P–V and T–S diagrams are traced and the heat and work are measured. Run it backwards as a refrigerator or heat pump.
SHM as Projection of Circular Motion
A ball goes round a circle at a steady speed and a lamp throws its shadow on a screen. The shadow moves up and down in simple harmonic motion, in step with a mass on a spring. Change the radius, the angular speed and the starting angle, and find out how the shadow’s position depends on the angle.
Displacement, Velocity and Acceleration in SHM
A block on a spring slides to and fro on a frictionless track. Watch its displacement, velocity and acceleration graphs build up together, see how the energy passes between the spring and the block, and find the rule a = −ω²x from your own readings.
Superposition of Two Waves
Send two pulses or two waves along a rope with any amplitudes, wavelengths, speeds and phase difference. See y₁, y₂ and their sum point by point, and find the cosine law for the resultant amplitude from your own readings.
Beats
Sound two tuning forks of nearly equal frequency and hear the loudness rise and fall. Count the beats with a stopwatch, find that beats per second = |n₁ − n₂|, and use wax to find the frequency of an unknown fork.
Stationary Waves: Nodes and Antinodes
A string tied to a vibrator runs over a pulley to a weight hanger. Change the frequency, the load or the string and watch steady loops form only when the frequency matches a natural mode, with nodes, antinodes and the two travelling waves that make them.
Harmonics of a Stretched String
Pluck or bow a real instrument string and see it as a sum of its modes. Move the pluck point and watch harmonics vanish from the spectrum, hear the result, and measure the frequencies to discover the harmonic series n_p = p n₁.
Vibrating Air Columns: Closed and Open Pipes
Choose a pipe closed at one end or open at both ends, give it any length, width, gas and temperature, and watch the air inside vibrate as a standing wave. Hear the note, compare the harmonics of closed and open pipes, and find the speed of sound and the end correction from your own readings.
Half-Wave Rectifier
A step-down transformer, one diode and a load on a trainer board, with a two-channel CRO and a multimeter. Change any value, add a filter capacitor and watch current flow only in the conducting half-cycle.
Full-Wave Rectifier and Filter
Centre-tap or bridge rectifier with any transformer, diodes, load and filter. See which diodes conduct in each half-cycle, compare the CRO trace with a half-wave rectifier and measure how a capacitor or π filter cuts the ripple.