Physics
Physics projects for class 1 to 5: 83 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 1 to 5: Chemistry, Biology, Maths, Earth and space, Electronics and robotics, Environment, Computing and coding.
Balloon-powered car
Air rushing backwards out of the balloon pushes the car forwards. This is Newton’s third law: every action has an equal and opposite reaction.
Magnetic fishing game
Magnets attract things made of iron and most kinds of steel, but not paper, plastic, wood, aluminium or copper.
Paper cup telephone
Sound is a vibration. Your voice makes the cup vibrate, the tight string carries the vibration, and the other cup turns it back into sound.
Simple electric circuit with a switch
Electricity flows only round a complete loop. The switch opens and closes the loop, turning the bulb off and on.
Sink or float, and the clay boat
Whether something floats depends on its density and its shape. A ball of clay sinks, but the same clay shaped into a boat floats, because it pushes aside more water.
Air pressure holds up water
Air pushes on everything around us. When the glass is turned over, the air pressure pushing up on the card is enough to hold the water in.
CD hovercraft
Air from the balloon forms a thin cushion under the CD. The cushion cuts friction with the table, so the hovercraft glides.
Bottle-cap water wheel that lifts a weight
Falling water pushes on the cups of the wheel and makes it turn. The turning axle winds up a thread and lifts a small weight, so the energy of moving water becomes useful work.
Thread spool crane with a fixed pulley
A single fixed pulley does not make a load lighter, but it changes the direction of the pull, so you lift a load up by pulling down. That is why cranes, flagpoles and wells use pulleys.
Ruler seesaw: balancing coins at different distances
A lever balances when the weight times its distance from the pivot is equal on both sides. One coin far from the middle balances two coins placed half as far away.
Shoebox shadow theatre: light travels in straight lines
A shadow forms because light travels in straight lines and cannot bend round an object. Moving the puppet nearer the torch makes its shadow larger and fuzzier; nearer the screen makes it smaller and sharper.
How a stick’s shadow changes through the day
The shadow of a fixed stick is long in the morning, shortest around midday and long again in the evening, and it swings from west to east as the Sun moves across the sky. Shadow length depends on how high the Sun is.
Tissue box rubber band guitar: what changes the pitch?
Sound is made by vibration. A thin, tight or short rubber band vibrates faster and gives a higher note; a thick, loose or long one vibrates slower and gives a lower note. The hollow box makes the sound louder.
Water bottle xylophone: pitch and the amount of water
Tapping a glass bottle makes the glass and the water vibrate, and more water makes the vibration slower and the note lower. Blowing across the top vibrates the air instead, so the bottle with the most water gives the highest note.
Dancing rice drum: seeing sound vibrations
Sound travels through the air as vibrations. A loud sound near a stretched plastic sheet makes the sheet vibrate, and grains of rice on it jump, even though nothing touches the drum.
Why does a clay ball sink but a clay boat float?
The same lump of clay sinks as a ball but floats as a bowl, because the bowl shape pushes aside much more water. Floating depends on the shape and the water displaced, not only on the weight.
How much salt makes an egg float?
An egg sinks in plain water but floats in salty water. Dissolving salt makes the water denser, so it pushes up harder on the egg. Measuring the salt needed turns a trick into a real experiment.
Balloon in a bottle: air takes up space
A balloon hung inside a sealed bottle will not blow up, because the air already in the bottle has nowhere to go. Make a small hole in the bottle and the balloon inflates easily, proving that air is real and takes up space.
Which shoe sole grips best? Friction on a tilting ramp
Friction is the force that stops things sliding. A rough rubber sole needs the board to be tilted much more steeply before it slides than a smooth plastic sole, so the angle at which an object starts to slide is a simple measure of friction.
What can a magnet pull through? Paper, cloth, wood and water
A magnet’s pull passes through paper, cloth, plastic, glass, wood and water, but gets weaker with distance. Only iron, steel and a few other metals block or are pulled by it, and a thick steel sheet shields the pull.
Floating needle compass that finds north
Stroking a steel needle with a magnet turns it into a weak magnet. Floated on water so it can turn freely, the needle lines up north to south, because the Earth itself acts like a giant magnet.
Paper spiral snake that spins over warm air
Warm air is lighter than cool air and rises. A paper spiral hung above a warm surface spins as the rising air pushes on its sloping coils, showing convection, the way heat spreads in air and water.
Black tin versus white tin: which gets hotter in the sun?
A dark surface soaks up most of the sunlight that falls on it and gets hot, while a white or shiny surface reflects most of it and stays cooler. This is why we wear light colours in summer and why solar heaters are painted black.
Bottle with three holes: water pressure grows with depth
Water squirts furthest from the lowest hole in a bottle, because the weight of all the water above it presses on it. Pressure in a liquid increases with depth, which is why dam walls are thickest at the bottom.
Ice cream stick catapult: how far does a pom-pom fly?
Pulling the arm down stores energy in the bent stick and rubber bands, and letting go turns it into the motion of the pom-pom. More bend means more stored energy and a longer flight, and the launch angle changes the distance too.
Paper helicopter: wing length and fall time
A strip of paper with two folded wings spins as it falls, because air pushing on the slanted wings makes it turn. Longer wings catch more air and slow the fall, while adding paper clips makes it fall faster. Air resistance is a real force.
Plastic bag parachutes: does a bigger canopy fall slower?
A parachute slows a fall because its wide canopy pushes against a lot of air. Bigger canopies take longer to fall with the same load, and a small hole in the top makes the fall steadier instead of swinging.
Balloon rocket on a string: action and reaction
Air rushing out of the balloon’s neck pushes the balloon the other way along the string. The bigger the balloon, the further it travels. This is Newton’s third law, the same rule that lifts a real rocket.
Cardboard bird that balances on a fingertip by its beak
A cardboard bird with coins hidden in its wing tips balances on its beak and even wobbles back upright when pushed. Adding weight far forward and low moves the bird’s centre of gravity to just below the beak, so it cannot topple.
Cardboard castle drawbridge raised by thread and spools
A drawbridge is a lever hinged at one end, raised by threads that run over pulleys at the top of the gate and are wound on an axle. The model shows how a lever, pulleys and a wheel and axle work together to lift a load with a gentle turn of a handle.
Village well model: a wheel and axle that lifts a bucket
Turning a large wheel moves a small axle with greater force, so a bucket of water can be lifted with a light push on the handle. The bigger the handle circle compared with the axle, the easier the lift but the more turns needed.
A screw is a wrapped ramp: paper triangle on a pencil
Wrapping a paper triangle round a pencil turns its sloping edge into a spiral thread, just like a screw. A screw is an inclined plane wound round a rod, which is why it goes in with little force but needs many turns.
Steel spoon mirrors: why one side flips your face
The back of a shiny spoon is a convex mirror and always shows a small, upright, wide view. The bowl side is a concave mirror: it shows your face upside down from far away and large and upright when very close.
Kaleidoscope from old CD case strips and a chips tube
Three mirrors set in a triangle reflect light again and again, turning a few coloured beads into a symmetrical pattern of many images. It shows how reflection works and how multiple reflections multiply images.
Making a rainbow with a mirror in a bowl of water
Sunlight looks white but is a mixture of colours. Water with a mirror in it acts like a prism, bending each colour by a slightly different amount, so the reflected beam fans out into red, orange, yellow, green, blue, indigo and violet on the wall.
The bending pencil: refraction in water, oil and glass
A pencil standing in a glass of water looks broken at the surface because light bends when it passes from water into air. Different liquids bend light by different amounts, and a coin hidden under the rim of a cup reappears when water is poured in.
Water drop magnifier: a lens from a single drop
A drop of water on clear plastic has a curved top, like a convex lens, and makes small print look bigger. A rounder, smaller drop magnifies more. It shows how lenses in magnifying glasses, spectacles and microscopes work.
Spinning colour disc: seven colours blend into white
A disc painted with the seven rainbow colours looks almost white when spun fast, because the eye cannot keep up and mixes the colours together. White light is a mix of all colours, which is the reverse of a prism splitting it.
Twanging ruler: how length changes pitch and loudness
A ruler held over the edge of a table and twanged vibrates and makes a sound. A short overhang vibrates fast and gives a high note; a long overhang vibrates slowly and gives a low note. A harder twang makes a louder sound but not a different note.
Cardboard ear trumpet that collects faint sounds
A wide cone gathers sound waves from a large area and funnels them into the ear, so faint sounds become louder and clearer. Used the other way round, it sends your voice in one direction like a megaphone.
Which spinning top lasts longest? Paper plate and bottle-cap tops
A top stays upright while it spins fast, then wobbles and falls as friction slows it. Tops with a wide, heavy rim and a sharp point usually spin for longer.
Rubbed balloon lifts paper bits and bends a thin stream of water
Rubbing a balloon on hair gives it an electric charge. A charged object attracts light things like paper bits and even bends a stream of water.
Which spoon gets hot first? Steel, wood and plastic with butter and beads
Heat travels along a solid by conduction. Metals pass heat quickly, while wood and plastic pass it slowly, so a bead stuck on a metal spoon with butter drops off first.
Blow over a paper strip and watch it rise: fast air, low pressure
When you blow across the top of a paper strip it lifts instead of staying down. Fast-moving air has lower pressure than still air, so the stronger pressure below pushes the paper up.
Coin drops into a glass when the card is flicked: inertia tricks
Objects keep their state of rest unless a force acts on them. When the card is flicked quickly, the coin does not move sideways and drops straight down into the glass.
Which ball bounces highest? Drop height and floor surface test
A ball stores energy when it is squashed and gives most of it back as it bounces. Different balls and surfaces return different fractions of the energy, so the bounce height changes.
Pepper runs from soap: surface tension and a soap-powered boat
The surface of water behaves like a thin stretched skin. Soap weakens this skin where it touches, so the stronger pull from the surrounding water drags the floating pepper outwards.
Tin-can telephone: does a tight string carry sound better?
Sound travels along a taut string as vibrations. A loose string cannot carry the vibration well, so the voice becomes faint.
Drinking straw pan pipes: tube length and pitch
A shorter air column vibrates faster and gives a higher pitch. Seven straws of different lengths make a simple scale.
Paddle-wheel boat from a bottle and a rubber band
The wheel pushes water backwards and the water pushes the boat forward, as in Newton’s third law. The twisted rubber band supplies the energy.
Ice-cream stick tilt maze: guiding a marble by gravity
A marble always rolls downhill. Tilting the board changes its direction and speed, so the player has to plan the slopes.
Balloon-skin tin can drum where sound makes rice dance
Sound is a vibration. When a loud sound hits the stretched balloon, it vibrates and makes grains of rice jump, so we can see the vibration.
The pepper that runs away from soap: surface tension
The surface of water acts like a thin stretched skin that holds light grains of pepper on top. A touch of soap breaks this skin in one place, and the pepper rushes away from it.
How strong is paper? Folds, tubes and a stack of books
A flat sheet of paper is weak, but when it is folded into a tube, a fan or a triangle it can carry heavy books. You test different shapes of paper to see which holds the most.
Wrap an ice cube: foil, wool, newspaper or cloth?
Insulators slow the flow of heat into an ice cube, so it melts more slowly. By wrapping equal cubes in different household materials and weighing the meltwater, you find which ones insulate best.
Glass bottle xylophone: water level and pitch
The pitch of a note from a tapped bottle depends on the amount of water in it: more water gives a higher note when tapped. You tune bottles into a scale and learn how vibration speed sets pitch.
The spoon that rings like a bell: sound through string
Vibrations pass much better through a solid string than through air. A steel spoon hung from a string and tapped on a table sounds faint, but when you press the string to your ear it rings like a deep bell.
Straw rocket launcher: which fin shape flies the farthest?
A paper rocket is pushed off by a puff of air, and its fins keep it pointing straight. Changing only the fin shape while keeping everything else the same is a fair test of how fins help flight.
Paper planes: dart, glider and wide-wing flight distance and time
A paper plane flies by gliding: its wings make lift and the nose is pushed forward by the throw, while drag slows it. Different shapes trade speed for glide time.
Sound guessing jars: shake and listen
Different things make different sounds when shaken, because hard, soft, big and small things hit the inside of the jar differently. We can use hearing to work out what is hidden.
Which fruits and vegetables float? Predict and test
Some fruits and vegetables float and some sink in water, depending on how much of the body is air and how heavy it is for its size. Predicting before testing is how scientists work.
Foil boat: how many coins can it carry before it sinks?
The shape of a boat decides how much it can carry. A wide boat with high sides pushes aside more water and so carries more than a flat sheet.
Magnet treasure hunt: what in my home is magnetic?
A magnet attracts only some materials, mostly those with iron. Many things that look metallic, like a steel spoon or a coin, may not be magnetic.
Magnet pole push: two toy cars that chase and run away
Every magnet has two poles. Unlike poles pull together and like poles push apart, and we can use the push to move a small car without touching it.
Paint mixing: a colour wheel from red, yellow and blue
Three paints, red, yellow and blue, can be mixed to make many other colours. Mixing shows how colours relate to each other.
Torch and coloured cellophane: mixing lights on a wall
Coloured light mixes differently from paint. Where beams of red, green and blue light overlap, we see new colours, and all three together look almost white.
Hand shadow animals: big and small shadows with a torch
A shadow forms when something blocks light. The nearer the object is to the light, the bigger and softer the shadow is.
Toy shadow length: does a higher torch make a shorter shadow?
The length of a shadow depends on where the light is. A high light gives a short shadow and a low light gives a long one, like the Sun at noon and in the evening.
Toy car ramp: does a steeper slope make the car go farther?
A car rolling down a slope speeds up. A steeper ramp gives it more speed, so it rolls farther along the floor.
Pencil rollers: how wheels help move a heavy box
Rolling is easier than sliding. Rollers under a load reduce the friction, which is how the wheel was a great invention.
Cardboard gears with paper teeth that turn each other
Two gears with teeth that mesh turn in opposite directions, and a small gear spins faster than a big one.
Drinking straw whistle: shorter straw, higher sound
Sound is made by vibrations. A shorter vibrating column of air gives a higher sound, and a longer one gives a lower sound.
Comb and paper kazoo: feel your voice buzz
Vibrating paper makes a buzzing sound louder. We can feel the vibration on our lips.
Does sound travel through water? The spoon and bowl test
Sound can travel through liquids and solids as well as air. In water it travels even faster than in air.
Feel your voice: humming throat and dancing salt on cling film
Voice is a vibration. We can feel it in the throat and see the vibration make salt grains jump on a stretched sheet.
Ice cube melting: sun, shade, cloth and steel plate
Heat melts ice. The speed of melting depends on how warm the place is and whether the ice is covered or not.
Does water take up more room when it freezes?
Water expands a little when it freezes. Ice takes up more space than the same water, which is why ice floats.
Simple diamond paper kite and a flying test
A kite flies because wind pushes on it at a slant and string holds it. The tail keeps it steady.
Paper plane race: which fold flies the farthest?
Wing shape and fold change how far a plane flies. A fair test means launching each plane the same way and measuring the distance.
Paper clip on the nose: does weight help a plane glide?
The position of weight changes how a plane flies. A little weight in the front makes it steady, but too much makes it dive.
Paper pinwheel that spins in the breeze
Moving air can push on slanted blades and make them turn. Wind energy is used the same way in windmills.
Static comb: lifting paper bits and bending a water stream
Rubbing some things together gives them an electric charge, called static electricity. A charged comb can pull tiny paper bits and bend a thin water stream.
Rain stick from a cardboard tube: the sound of falling rain
Many grains falling past obstacles make a sound like rain. We hear the vibrations of grains hitting the tube walls and the pins.