Physics
Physics projects for class 9 and 10: 100 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 9 and 10: Chemistry, Biology, Maths, Earth and space, Electronics and robotics, Environment, Computing and coding.
Hydraulic arm with syringes
Pressure applied to a liquid in a closed system is passed on equally in every direction (Pascal’s law), so pushing one syringe moves its partner and lifts the arm.
Electromagnet
An electric current in a coil of wire makes a magnetic field. Wound round an iron nail, the coil becomes a magnet you can switch off, and more turns of wire make it stronger.
Simple electric motor
A coil carrying current in a magnetic field feels a force and turns. Scraping the insulation off only half of one end switches the current on and off at the right moments, so the coil keeps spinning.
Wind turbine that lights an LED
A small DC motor works as a generator when its shaft is turned: the spinning blades turn motion energy into electrical energy that lights the LED.
Plastic bottle vacuum cleaner
A small fan blows air out of the back of the bottle, lowering the pressure inside, so outside air rushes in through the nozzle carrying dust and paper bits with it.
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.
Human eye and its defects
The eye lens focuses light on the retina. In short sight the image forms in front of the retina and a concave lens corrects it; in long sight it forms behind the retina and a convex lens corrects it.
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.
Hydroelectric power plant model
Water stored high up has potential energy. As it falls it turns a turbine, and a generator on the turbine’s shaft turns that motion into electricity.
Water bottle rocket
Pumped-in air pushes the water out of the nozzle downwards, and the rocket is pushed upwards (Newton’s third law). A little water gives far more thrust than an empty bottle.
Ohm’s law checked on a pencil-lead resistor with a V-I graph
For a graphite pencil lead at steady temperature, the current through it is directly proportional to the voltage across it. The V against I graph is a straight line through the origin and its slope is the resistance (Ohm’s law, V = IR).
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.
Demonstration board comparing series and parallel torch bulbs
In a series circuit the same current flows through every bulb and the voltage is shared, so each bulb glows dimly and all go out if one is removed. In parallel each bulb gets the full cell voltage, glows brightly, and the others stay lit when one is removed.
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.
Electromagnet lifting power against number of turns and current
The strength of an electromagnet grows with the number of turns of wire and with the current through it. Counting the pins it lifts for 20, 40, 60 and 80 turns gives a clear upward trend.
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.
Mapping magnetic field lines of bar magnets and a current-carrying wire
A small compass points along the magnetic field at each point, so plotting its direction step by step traces the field lines of a magnet. A wire carrying current also deflects the compass, showing that electric current produces a magnetic field (Oersted’s experiment).
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Archimedes’ principle with an overflow can and a rubber-band balance
An object put in water seems lighter by exactly the weight of the water it pushes aside. The loss of weight, measured on a balance, equals the weight of the overflowed water.
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.
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.
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.
Rolled newspaper tube bridge: how much can it carry?
A flat sheet of paper bends easily, but the same paper rolled into a tube becomes strong. The bridge shows how shape, not material, decides strength.
Ice-cream stick truss bridge that spans 40 cm
A truss turns a downward load into pulling in some sticks and pushing in others. Triangular patterns share the load, so a light bridge can carry many times its own weight.
CD and paper Newton colour disc that turns white when spun
White light is a mixture of the seven spectrum colours. When a disc painted in rainbow sectors spins fast, the eye blends the colours and sees a pale white or grey.
Shoebox spectroscope using a piece of CD as a grating
A CD has fine tracks that spread light into colours by diffraction. The spectroscope shows that different bulbs and tubes have different colour patterns.
Syringe-powered hydraulic arm from cardboard and ice-cream sticks
Pushing a liquid in a closed system passes the force along without loss, so a small push at one syringe moves the arm at another. It is the idea behind brakes and JCBs.
Archimedes screw water lifter from a bottle and a plastic tube
Turning a spiral of tube lifts water uphill without a pump. The device is a screw that lifts water in a few turns, used for thousands of years.
Savonius wind turbine from two halves of a plastic bottle
A vertical turbine with curved cups catches the wind from any direction. It shows how kinetic energy of the wind is turned into rotation.
Pot-in-pot clay cooler: how evaporation keeps food cool
Water evaporating from wet sand between two clay pots takes heat from the inner pot. The test shows a temperature drop with no electricity.
Cardboard gear train with a cap handle and a measured speed ratio
Gears change speed and turning force. A small gear driven by a large one spins faster but with less force, and the speed ratio equals the ratio of teeth.
Straw and tape wave machine for transverse waves
A disturbance can travel along a line of objects without the objects moving along. The machine shows a transverse wave with crest, trough, wavelength and speed.
Principle of moments board from a ruler and paper-clip hooks
A beam stays balanced when the clockwise moment equals the anticlockwise moment. The board lets students test the rule with known weights.
Cardboard dam model that shows why a dam is thicker at the base
Water pressure grows with depth, so the base of a dam must be thicker than the top. The model has a spillway and a sluice gate and shows how stored water gives energy.
Newton’s cradle from marbles, thread and an ice-cream stick frame
When one ball hits a row of balls, the one at the far end swings out and the others stay still. This shows that momentum and energy are conserved in an elastic collision.
Pizza box solar oven that warms a cup of water
Foil reflects sunlight into the box, a clear cover traps heat, and a black cup absorbs it. The test shows how reflection, absorption and trapping of heat make a solar cooker.
Spool block and tackle that lifts a brick: counting the ropes
Several rope sections supporting a load share its weight. The mechanical advantage equals the number of supporting rope sections, so you pull a longer length with less force.
Popcorn: does soaking the kernels change how many pop?
Each popcorn kernel holds a tiny drop of water. When heated, the water turns to steam and builds pressure until the hard shell bursts. You test dry, lightly soaked and over-soaked kernels and count the percentage that pop.
Cooking time against size: potato cubes in boiling water
Heat moves into a potato from the outside by conduction, so a bigger piece takes much longer to cook through. By boiling cubes of different sides and noting when a fork goes in, you find the link between size and cooking time.
Sugar in fruit juice from the density of a floating egg
The more sugar a liquid holds, the denser it is. By making a density scale from sugar water and then floating a small object in juice samples, you estimate how much sugar is in the juice compared with a cola or squash.
Honey and oil flow: a marble drop viscosity test
Viscosity is how much a liquid resists flowing, and it falls quickly as the liquid warms. Timing a marble falling through honey or oil at different temperatures lets you measure this.
Boiling water at room temperature in a syringe: the pressure cooker idea
Water boils when its vapour pressure matches the pressure around it. Pulling the plunger of a sealed syringe lowers the pressure and makes warm water bubble, which is the same relationship that makes a pressure cooker cook faster when the pressure is raised instead.
Sticky tape strength: how overlap length changes the load it holds
The holding force of an adhesive tape is proportional to the area stuck down, so doubling the overlap should double the load it takes before peeling. You test the idea with strips and small weights and plot a graph.
Cooling curves of hot water: lid, no lid, wide and narrow pots
A hot liquid cools by evaporation, convection and radiation, and a lid or a narrow shape cuts the losses. You record temperature every five minutes and plot cooling curves for four setups.
How tall must a mirror be to see your whole body?
To see your whole body in a flat mirror, the mirror need be only half as tall as you, and it does not depend on how far you stand. You test this with a small mirror, a tape and a friend.
Water siphon from a kitchen tube: height difference and flow rate
A siphon moves water up and over a barrier without a pump, because the longer falling column of water pulls the liquid along. You measure how the height difference between two buckets changes the flow rate.
Which surface colour heats up fastest in the sun? Four can test
Dark and dull surfaces absorb more sunlight than light and shiny ones. The temperature rise of equal cans of water under the same sun shows which colour is best for a solar heater and which suits a roof.
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.
Vertical Savonius turbine from two halves of a plastic bottle
A vertical-axis wind turbine spins whichever way the wind blows. The curved half-bottle blades catch more push on the open side than the round side, so the rotor keeps turning.
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.
Overshot against undershot water wheel lifting the same load
Water can turn a wheel by weight from above (overshot) or by push from below (undershot). Timing how fast each wheel lifts a small weight shows which uses water more efficiently.
Hand-crank generator: voltage against cranking speed
Turning a small DC motor by hand makes a voltage, so the motor acts as a generator. Faster cranking gives higher voltage and brighter light, showing that mechanical energy changes into electrical energy.
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.
Pot-in-pot clay cooler that keeps vegetables fresh without electricity
Water evaporating from wet sand between two clay pots cools the inner pot. This is how farmers can store vegetables cooler without a fridge.
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.
Sprinkler irrigation model from a drilled pipe and a bucket head
A rotating or fixed sprinkler spreads water as small jets over a field. The model shows how water pressure, hole size and height decide how far and how evenly water falls.
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.
Canal lock model that lifts a boat between two water levels
A lock raises or lowers boats by letting water in or out of a chamber between gates. The model shows how water finds its own level and moves a boat with no engine lift.
Archimedes screw water lifter from a bottle and a coil of tube
A screw turning in a tilted tube lifts water upward, an idea used for thousands of years to irrigate fields. The model shows how a simple machine moves water uphill without a motor.
Hand pump model from a bottle, tube and two one-way flaps
A hand pump uses a piston and one-way valves to lift water from a well. The model shows how pushing and pulling the handle makes water move in one direction.
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.
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.
Gaganyaan-style crew capsule with a parachute to land an egg astronaut
A crew capsule coming back from space is slowed by a parachute and lands softly. A larger parachute canopy gives more air drag and a slower fall, which protects the passenger.
Bounce height of cricket, tennis and rubber balls on grass, concrete and sand
How high a ball bounces depends on both the ball and the surface. Some of the ball’s energy is lost as sound, heat and a dent in the surface at each bounce, which explains why pitches matter in cricket.
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.
Flat sole, studs and spikes: friction on a muddy tray
Friction is the force that stops a shoe from slipping. On wet mud, the grip depends on the sole pattern, because studs and spikes dig in and rubber flat soles slide on a film of water.
Ruler-drop reaction time: dominant hand, other hand and a warning sound
The distance a ruler falls before you catch it tells how fast you react. Comparing hands and signals shows what can speed up or slow down a response, which is important in cricket and sprint starts.
Kite flying physics: tail length, string angle and wind speed
A kite stays up because the wind pushes on it at an angle. The forces of wind, weight and string tension balance. A longer tail steadies the kite, and a higher wind speed raises the string angle.
Balance point of a cricket bat, a hockey stick and a bicycle pump
Every object has a balance point, the centre of gravity, where its weight seems to act. In sports equipment it is not at the middle, and where it lies changes how the object feels in the hand.
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.
Standing long jump: does an arm swing add distance?
The distance of a jump depends on the take-off speed and angle. Swinging the arms adds to the speed of the body’s launch, which is why athletes use them.
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.
30 metre sprint speeds of a class timed with a pair of stopwatches
Average speed equals distance divided by time. Timing a short run shows differences in speed in a class, and also how reaction time of the timekeeper can add error.
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.
Playground seesaw: where must two children sit to balance?
A seesaw balances when the turning effect (moment) on one side equals that on the other. A lighter child must sit farther from the pivot to balance a heavier child.
Carrom striker slide: how powder changes friction and stopping distance
Carrom players sprinkle fine powder on the board to make the striker glide. Measuring how far a striker slides with and without powder shows how a thin layer lowers friction.
Baking-tray ripple tank: reflection and refraction of water waves
A shallow tray of water lit from above shows ripples as bright and dark lines on white paper below. Ripples reflect from a barrier and bend when they pass from deep to shallow water, because waves travel more slowly in shallow water.
Speed of sound from an echo: clapping in time with a wall
If you stand about 50 m from a large wall and clap so that each clap meets the echo of the one before, the time between claps equals the time sound takes for the round trip. The distance and time give the speed of sound as about 340 metres per second.
Blowing over a tube: pitch against air column length
A tube closed at the bottom with water gives a note when you blow across the open top, and a shorter air column gives a higher pitch. The frequency is roughly inversely proportional to the length of the air column.
Electrophorus: charging a foil plate again and again by induction
A foil plate with an insulating handle can be charged over and over from one rubbed plastic sheet without losing the sheet’s charge. It shows charging by induction and earthing, and the plate can make a small spark in a dark room.
Latent heat of melting ice measured by mixing ice with warm water
Ice at 0 °C takes a large amount of heat to melt, without any rise in temperature. Mixing a known mass of ice into warm water and noting the final temperature lets us calculate this latent heat as about 334 joules per gram.
Cooling curve of hot water in a bare cup, a lidded cup and a wrapped cup
Hot water cools quickly at first and slowly later, because the rate of heat loss depends on how much hotter the water is than the room. A graph of temperature against time for three cups shows how a lid and a wrapping reduce heat loss.