Physics
Physics projects for class 11 and 12: 89 ideas.
Each project below opens to its own page with what it shows, the science behind it, the materials, safety, step-by-step instructions, what you should see and viva questions. Many can be made from things at home; where a kit helps, the page links one.
Other subjects for class 11 and 12: Chemistry, Biology, Maths, Earth and space, Electronics and robotics, Environment, Computing and coding.
AC generator (electromagnetic induction)
When a coil turns in a magnetic field, the changing magnetic field through it induces a current (Faraday’s law). The current reverses every half turn, which is alternating current.
Light trapped in a stream of water
Light inside the water meets the surface at a large angle and is totally internally reflected, so it follows the curved stream. Optical fibres carry internet signals the same way.
Full wave bridge rectifier
Four diodes arranged as a bridge send current through the load in the same direction on both halves of the AC cycle, turning AC into pulsating DC. A capacitor smooths the output.
Logic gates with diodes and a transistor
Two diodes and a resistor make AND and OR gates, and a transistor makes a NOT gate. Switches give the inputs and an LED shows the output, matching each gate’s truth table.
Transformer working model
Alternating current in the primary coil makes a changing magnetic field in the iron core, which induces a voltage in the secondary coil (mutual induction). In an ideal transformer the voltages are in the same ratio as the numbers of turns.
Magnet falling through a copper pipe (Lenz’s law)
A falling magnet induces eddy currents in the copper pipe. By Lenz’s law these currents make a magnetic field that opposes the motion, so the magnet falls far more slowly than a non-magnetic object.
Refractive index of liquids by real and apparent depth
A coin under water looks raised, because light bends as it leaves the water. The refractive index is the real depth divided by the apparent depth, so different liquids give different values.
Footstep power with piezo discs
Piezoelectric discs make a small voltage when they are pressed. Many discs under a tile, with a rectifier and a capacitor, can light LEDs, though the energy from each step is very small.
How resistance changes with the length and thickness of nichrome wire
The resistance of a wire is directly proportional to its length and inversely proportional to its area of cross section (R = rho L / A). Doubling the length doubles R, and twisting two equal wires together halves it.
Internal resistance and emf of a dry cell from a V-I graph
The terminal voltage of a cell falls as it supplies more current because of its internal resistance, following V = E minus I r. A graph of V against I is a straight line whose intercept is the emf E and whose slope is minus r.
Conductivity of salt water against concentration with two carbon rods
Pure water barely conducts, but dissolved salt gives free ions that carry current. The current through a salt solution rises with concentration at first and then levels off as the ions crowd each other.
Homopolar motor from a screw, a cell and a neodymium magnet
A current flowing through a magnet in a magnetic field feels a sideways force (F = B I L), and here that force makes the magnet and screw spin at hundreds of revolutions per minute. It is the simplest motor that works with no coil and no commutator.
Shake torch: a magnet moving through a coil lights an LED
Moving a magnet through a coil changes the magnetic flux through it and induces an emf (Faraday’s law), which lights an LED with no cell at all. Faster shaking and more turns give a brighter flash.
Eddy current brake: a metal plate pendulum swinging between magnets
A solid aluminium or copper plate swinging between magnet poles stops within a few swings, while a slotted plate swings on, because circulating eddy currents are induced in the solid plate and Lenz’s law makes them oppose the motion. This is how train and roller-coaster magnetic brakes work.
Thermocouple from copper and iron wire read with a multimeter
Two different metals joined at two points produce a small voltage when the two junctions are at different temperatures (the Seebeck effect). The voltage rises roughly in proportion to the temperature difference, which is how thermocouple thermometers work.
Forward voltage of LEDs of different colours and the energy of light
An LED only begins to conduct above a threshold voltage that is higher for colours of shorter wavelength: red about 1.8 V, green about 2.1 V, blue about 2.8 V. The threshold energy e V roughly equals the photon energy h c / lambda, so this experiment gives an estimate of Planck’s constant.
Charging and discharging a capacitor: the RC time constant with a stopwatch
A capacitor charging through a resistor reaches 63 percent of the supply voltage after one time constant tau = R C, and discharges to 37 percent in the same time. With a large capacitor and a large resistor the process takes tens of seconds, slow enough to time by hand and to plot.
Metre bridge on a plank: finding an unknown resistance by balance
A Wheatstone bridge is balanced when the galvanometer shows zero, and then the unknown resistance equals the known one multiplied by the ratio of the two wire lengths (X = R l / (100 minus l)). A home-built metre bridge measures resistors to within a few percent.
Home-made tangent galvanometer: compass deflection against coil current
A compass at the centre of a vertical coil set in the magnetic north-south plane is deflected by the coil’s field, and the tangent of the deflection angle is proportional to the current (tan theta = B_coil / B_H). This measures current and even the horizontal component of Earth’s field.
Joule heating: water temperature rise against voltage
An electric current heats a resistor, and the heat produced in a fixed time is V squared divided by R, times t. Doubling the voltage on the same coil makes it deliver four times the heat.
Maximum power from a cell: power against load resistance graph
A cell delivers the most power to a load when the load resistance equals the cell’s own internal resistance. The power curve rises, peaks and falls as the load is changed.
Potential divider: output voltage from a pencil lead and an LDR
Two resistors in series share the cell’s voltage in proportion to their resistances. Replacing one with an LDR makes the output voltage change with light, which is how many sensors work.
Diode V-I characteristic with cells: forward knee and reverse leakage
A silicon diode conducts almost nothing until the forward voltage reaches about 0.6 to 0.7 V, then the current rises steeply. In reverse it passes almost no current.
Slide-wire potentiometer to compare the emf of two cells
On a uniform wire carrying a steady current, the voltage falls evenly along its length. The balance lengths for two cells are in the same ratio as their emfs, and no current is drawn from the cells at balance.
Force on a current carrying wire: swinging foil strip in a magnet gap
A wire carrying current in a magnetic field feels a sideways push, F = B I L. Reversing the current or the magnet reverses the push, as Fleming’s left-hand rule says.
How a bar magnet’s field falls with distance: compass log graph
Far from a magnet the field along its axis falls roughly as the cube of the distance. A compass needle’s deflection, compared with the Earth’s field, lets you check this from a log graph.
Torch bulb V-I curve: why a hot filament is not ohmic
A bulb’s filament gets hotter as the current rises, and a hotter metal resists more. The graph of voltage against current therefore bends and the bulb does not obey Ohm’s law.
Kirchhoff’s current and voltage laws on a two-loop resistor board
At any junction the currents entering equal the currents leaving, and round any closed loop the voltages add to zero. A two-loop board with two cells shows both laws with measured values.
Induced emf against magnet speed: dropping a magnet through a coil
Faraday’s law says the emf in a coil equals the rate of change of magnetic flux. A magnet falling faster through the same coil gives a larger voltage pulse.
Convex lens focal length from a u-v graph on a metre rule bench
A convex lens forms a real, inverted image on a screen at a distance that depends on where the object is. The lens formula links the two distances to the focal length, and a graph of 1/v against 1/u gives f accurately.
Bessel’s displacement method: focal length without finding the lens centre
If an object and a screen are further apart than four focal lengths, there are two lens positions that give a sharp image. The distance between them gives f from f = (D² − d²) / 4D.
Concave mirror: where the image forms and how big it is
The size, position and nature of the image in a concave mirror change as the object moves from far away to inside the focal length. The mirror formula and magnification can be checked with real readings.
Critical angle of water: the vanishing pin under a floating disc
Rays from an object under water that meet the surface at more than the critical angle are totally reflected and cannot leave. A disc on the surface can hide a pin completely when its radius is large enough, which gives the refractive index.
Glass slab pin method: Snell’s law from a sin i against sin r graph
Light going from air into glass bends toward the normal so that sin i / sin r is a constant, the refractive index. A graph of sin i against sin r for several angles has a slope equal to that index.
Glass prism: angle of deviation against angle of incidence curve
A ray bent by a prism is deviated by an angle D that first falls and then rises as the angle of incidence increases, with a minimum in the middle. The refractive index follows from the minimum deviation and the prism angle.
Two-lens compound microscope model with measured magnification
A short focal length objective makes a magnified real image, and a second lens, the eyepiece, magnifies that image again. The total magnification is the product of the two.
Two-lens astronomical telescope: magnifying power equals f0 divided by fe
A long focal length objective and a short focal length eyepiece make a refracting telescope. In normal adjustment its angular magnification is f0 / fe.
Two polarising filters: Malus’s law with a phone light sensor
Light passing through a second polarising filter is cut down by cos² of the angle between the two filters’ axes. Measuring the light level against the angle verifies Malus’s law.
Measuring the track spacing of a CD with a laser pointer
A CD’s closely spaced tracks act as a reflection diffraction grating. A laser pointer makes spots on a wall whose angles give the spacing of the tracks, about 1.6 micrometres, from d sin θ = n λ.
Inverse square law of light with an LED and a phone lux meter
The brightness of a small light source falls with the square of the distance. Doubling the distance cuts the light to a quarter.
Newton’s law of cooling: temperature curve and ln graph of hot water
A hot body cools at a rate proportional to its excess temperature over the surroundings. A graph of the natural log of the excess temperature against time is a straight line.
Specific heat of metal pieces by the method of mixtures
Different metals need different amounts of heat to warm by one degree. Dropping hot metal into cool water and measuring the final temperature gives the metal’s specific heat.
Butter dabs on metal rods: which metal conducts heat best
When one end of equal rods is heated, the heat travels along each at a different speed. Dabs of butter melt in order along the rod, showing which metal is the better conductor.
Latent heat of fusion of ice by mixing with warm water
Melting ice absorbs a lot of heat without changing temperature. Mixing dry ice at 0 degrees C into warm water and measuring the final temperature gives the latent heat of fusion, about 334 joules per gram.
Linear expansion of a metal rod magnified by a rolling-needle pointer
A metal rod lengthens by only a fraction of a millimetre when heated. A pointer fixed on a rolling needle magnifies the tiny change so that the coefficient of linear expansion can be measured.
Resonance tube: speed of sound using a phone tone generator
An air column closed at one end resonates when its length is a quarter or three quarters of the wavelength. Two resonance lengths give the speed of sound without needing to know the end correction.
Echo clapping rhythm: speed of sound from a distant wall
Sound takes time to reach a wall and return. If you clap so that each clap meets the echo of the last, the time between claps is the echo time, so speed = 2 × distance ÷ time.
Sonometer string: frequency against length and tension
The pitch of a stretched string rises when it is shortened or tightened. The frequency is inversely proportional to the length and proportional to the square root of the tension.
Blowing across a bottle: Helmholtz resonance frequency against air volume
Air in a bottle with a narrow neck resonates at a frequency that falls as the bottle’s air volume gets bigger. Adding water makes the note rise.
Chladni patterns: salt figures on a speaker-driven metal plate
A vibrating plate has nodal lines where it stays still, and sprinkled salt collects on them to draw beautiful patterns. Each pattern belongs to one natural frequency of the plate, and higher frequencies give more complex figures.
Newton’s second law: trolley pulled by a falling weight
The acceleration of a trolley is proportional to the force on it and inversely proportional to its mass. A falling weight pulls the trolley, and distance-time measurements give the acceleration.
Two toy car collisions: checking momentum with slow-motion video
In a collision the total momentum of two cars is the same before and after, even though some kinetic energy is lost. Slow-motion video gives the speeds.
Rubber band launcher: range against launch angle, maximum at 45 degrees
A ball launched at the same speed travels farthest when the angle is about 45 degrees, and two angles that add to 90 degrees give the same range. This follows from R = v² sin 2θ / g.
Rolling race on a slope: hollow can, solid cylinder and ball
Objects of the same mass and radius roll down a slope at different speeds, because their mass is spread differently. The ball wins and the hollow ring comes last, and the rolling acceleration can be calculated from the moment of inertia.
Whirled rubber bung: checking the centripetal force formula
A body moving in a circle needs an inward force of m ω² r. Whirling a bung on a string with a hanging weight pulling it inwards shows that this force equals the weight.
A marble falling in honey: viscosity from terminal speed
A ball falling in a thick liquid reaches a steady speed where the drag balances its weight less the buoyancy. Stokes’s law then gives the liquid’s viscosity from that speed.
Straw hydrometer: calibrating a float to measure liquid density
A weighted straw floats lower in a lighter liquid and higher in a denser one. Marking it in liquids of known density turns it into a hydrometer.
Capillary rise of water against tube radius: Jurin’s law with glass tubes
Water climbs up a narrow glass tube and goes higher in a narrower one. The height is inversely proportional to the radius, and the measured heights give the surface tension of water.
Hooke’s law and spring oscillations: T² against load graph
A spring stretches in proportion to the load, and a mass hanging on it bobs up and down with a period that depends on the mass and the spring constant. The two experiments give the same spring constant.
Finding g with a simple pendulum: T² against length graph
The square of a pendulum’s period is proportional to its length, with slope 4π² / g. The slope of the graph gives the acceleration due to gravity at your place.
Solar cell I-V curve: maximum power point and fill factor
A solar cell behaves like a current source up to a knee and then like a diode. Its power peaks at one load, the maximum power point, and the fill factor shows how close the curve is to a perfect rectangle.
Savonius wind turbine from cans: lifting a weight at different wind speeds
A vertical-axis turbine with two curved scoops spins in a wind, and the turning axle winds up a thread to lift a weight. The useful power it delivers can be compared with the power in the wind, which is ½ ρ A v³.
Spoon Pelton wheel: output power and efficiency against water head
A jet of water hitting spoon-shaped buckets turns a wheel that lifts a weight. The power in the jet is ρ g Q H, and comparing it with the power lifting the weight gives the efficiency.
Solar cell I-V curve and maximum power point with a potentiometer load
A solar panel is not a battery: its voltage and current change with the load. By plotting current against voltage and power against voltage, a student finds the maximum power point, fill factor and effect of shading, which are the basis of MPPT charge controllers.
Peltier mini cooler box: temperature drop with different heat sinks
Mini fridges for medicines and vaccines in remote places use Peltier modules, which pump heat electrically without gas. The project builds a small insulated box and shows that how well the hot side is cooled decides how cold the box becomes.
DC motor torque-speed curve and back EMF measured with a rope brake
Selecting a motor for a robot or pump needs its torque-speed curve and efficiency. A homemade rope brake loads a small motor with known torque, while voltage, current and rpm are measured to plot the characteristics and show the back EMF effect.
Rotating-magnet coil generator: output voltage against speed and turns
Bicycle dynamos and wind turbines make electricity from a moving magnet near a coil. The project builds a model generator and tests how peak voltage depends on the speed of rotation and the number of turns, which is Faraday’s law in action.
Falling magnet through a coil recorded with a phone sound card
A magnet dropped through a coil induces a voltage pulse, and one dropped through a copper pipe falls slowly because of eddy currents. The project records both events and measures how induced voltage depends on speed and how Lenz’s law slows the fall.
Slider-crank and scotch yoke models compared for piston displacement
Engines, compressors and pumps convert rotation to straight-line motion. A slider-crank gives a motion that is not quite sinusoidal, and a scotch yoke gives a perfect sine. The project builds both from plywood or acrylic and measures piston position against crank angle.
Spur gear train model testing speed ratio, torque and backlash
Gearboxes in bicycles, clocks and winches trade speed for torque. A model gear train made from salvaged toy gears or laser-cut MDF lets a student check that the speed ratio equals the inverse of the teeth ratio and measure backlash and losses.
Four-bar linkage wiper mechanism and its coupler curve plotted on paper
Windscreen wipers, bike pedals and door closers use four-bar linkages. A linkage turns one motion into another through four links and four pins. The project builds a crank-rocker model, traces the path of a point on the coupler and checks the Grashof rule for which links can rotate fully.
Cam and follower model: three profiles and their displacement diagrams
Engine valves and sewing machines use cams to give exact timed motion. The project cuts three cam profiles, measures the follower rise at each angle and plots a displacement diagram, which shows why the shape of the profile matters for smooth motion.
Warren truss bridge from ice-cream sticks tested to failure
Railway and road bridges use trusses because a triangle is rigid and each member carries either tension or compression. The project builds a Warren truss, loads it step by step until it fails, and compares the failure load with a simple member-force calculation.
Model footing on sand: bearing load against footing width and depth
Buildings stand on foundations that spread the load over soil. The project loads small square footings on a tray of sand and shows that a wider footing carries more total load but the same or lower pressure, and that burying the footing raises its capacity.
Simply supported wooden beam: deflection test and Young’s modulus estimate
Floors, shelves and bridges bend under load. A strip of wood supported at both ends and loaded at the middle bends by an amount that depends on its depth, length and Young’s modulus. The project measures the deflection and calculates the modulus for different woods.
How many clear layers does a solar heater plate need? Glazing test
A clear cover over a black plate lets sunlight in and slows heat from escaping. Testing zero, one and two layers shows the benefit and the point where extra layers stop helping.
Two, three, four or six blades: which rotor turns a dynamo best?
The number and angle of blades change how much electricity a small wind rotor makes. Measuring voltage for each design under the same fan shows the best design for a fixed wind speed.
Small solar cells in series and in parallel, with one cell shaded
Joining cells in series adds voltage, while joining them in parallel adds current. Shading one cell shows why a single shaded cell can cut the power of a whole panel.
Windmill pump model that lifts water with a crank and syringe
A windmill pump turns the spin of its blades into an up and down stroke that lifts water. It shows how farmers use wind to irrigate fields with no electricity.
Drip emitter flow against reservoir height: pressure head test
The rate at which a drip emitter releases water depends on the height of the water above it. Measuring drops per minute at different heights shows the link between pressure and flow, which a farmer uses to design a drip line.
Gravity dam profile model: why the base is thick and the top thin
Water pressure grows with depth, so dams are thicker at the bottom. A model dam in a tray of water shows that a trapezoid profile resists the push of water better than a thin wall.
Two-lens refracting telescope from a pair of magnifying glasses
A long-focus lens gathers light from a distant object and forms a small image. A second short-focus lens acts as a magnifier for that image, so far-away objects look larger and nearer.
Whirling ball orbit: how speed changes with string length
A ball on a string moving in a circle needs a steady inward pull. This pull mimics gravity for a satellite. For the same pull, a longer string needs a faster ball, while real planets nearer the Sun move faster because gravity there is stronger.
Doppler shift of a whirling buzzer, the idea behind galaxy redshift
A sound source moving towards you sounds higher in pitch, and one moving away sounds lower. Astronomers use the same idea with light to find that distant galaxies are moving away from us.
CD spectroscope that splits daylight, bulb and tube light
A CD acts as a diffraction grating, splitting light into colours. Different sources give different patterns of colour, and astronomers use the same idea to find what stars are made of.
Launch angle and range with a spring catapult: is 45 degrees best?
The range of a projectile depends on the launch angle. On level ground and with little air drag, the greatest range occurs at 45 degrees, and complementary angles such as 30 and 60 degrees give the same range.
Spinning paper-cup curve: the Magnus effect behind swing and spin bowling
A spinning object moving through the air curves sideways. A paper cup launched with a rubber band shows a curved flight, as a spinning cricket or football does.
Playground swing as a pendulum: does the rider’s weight change the time?
The time of a swing depends on its length and not on how heavy the rider is. A small model pendulum and a real swing both give a period close to 2 times pi times the square root of length over g.
Football air pressure and bounce height with a hand pump
The more air pressure inside a ball, the harder it is and the higher it bounces. A ball that is too soft loses a lot of energy because it squashes more on impact.