1029 science project ideas, from class 1 to college.

What it shows

Air from the balloon forms a thin cushion under the CD. The cushion cuts friction with the table, so the hovercraft glides.

You will need

• An old CD
• A pop-up bottle cap
• A balloon
• Glue

What it shows

Light reflects from a plane mirror at the same angle at which it arrives. Two mirrors at 45 degrees send the light down the tube, so you can see over a wall.

You will need

• Two juice cartons or a long cardboard box
• Two small mirrors
• Tape and scissors

Safety: Cover the mirror edges with tape.

What it shows

Winding the rubber band stores elastic potential energy, which turns into motion (kinetic) energy as it unwinds and turns the axle.

You will need

• Cardboard or a bottle for the body
• Old CDs or bottle caps for wheels
• Skewers or straws for axles
• Rubber bands
• Tape

What it shows

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.

You will need

• A plastic bottle
• A small DC motor with a fan cut from a bottle cap or tin
• A battery pack and a switch
• A mesh or cloth filter
• Wires and glue

Safety: Keep fingers away from the spinning fan.

What it shows

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.

You will need

• A fizzy-drink PET bottle
• Card fins and a nose cone
• A cork or a launcher with a valve
• A bicycle pump
• Water

Safety: Launch outdoors in an open space with an adult. Wear eye protection, never stand over the rocket, and do not over-pump.

What it shows

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.

You will need

• Eight plastic bottle caps (free)
• An old CD or a circle of stiff cardboard
• A pencil or a wooden skewer for the axle
• Two empty matchboxes or a small cardboard frame as stands
• About 50 cm of thread and a bottle cap with a few coins as the weight
• Hot glue or strong tape
• A jug of water and a tray

Safety: An adult must use the hot glue gun and make any cuts in the plastic.

Take it further: Fit a second, smaller wheel on the same axle and see whether the weight rises faster or slower when the thread winds on the smaller one.

What it shows

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.

You will need

• A shoebox or any cardboard box (free)
• White butter paper or tracing paper for the screen
• Cardboard for puppets and drinking straws or sticks for handles
• A torch or a mobile phone light
• Scissors, tape and glue

Safety: An adult must cut the window in the box; children cut only the puppets with safety scissors.

Take it further: Use two torches of different colours from two sides and see coloured, overlapping shadows.

What it shows

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.

You will need

• An empty tissue box or a shoebox with a hole cut in the lid (free)
• Five or six rubber bands of different thickness
• Two pencils to act as bridges
• Tape

Safety: Rubber bands can snap back and sting; pluck gently and keep them away from the face.

Take it further: Use a free phone tuner app to measure the frequency of each band and plot it against the band’s thickness.

What it shows

Liquids expand when heated and shrink when cooled. Coloured water in a sealed bottle rises up a narrow straw when the bottle is warmed and falls when it is cooled, which is exactly how a liquid thermometer works.

You will need

• A small glass or plastic bottle with a tight lid (free)
• A clear drinking straw
• Water and a few drops of food colour or ink
• Modelling clay, hot glue or candle wax to seal the straw into the lid
• A card strip and a pen for the scale
• Two bowls, one with warm water and one with cold water

Safety: An adult must make the hole in the lid and use hot glue; use warm tap water only, never boiling.

Take it further: Calibrate the scale by comparing with a real thermometer at two known temperatures and marking degrees in between.

What it shows

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.

You will need

• A 1 or 2 litre plastic bottle (free)
• A nail or a pin to make three holes, used by an adult
• Tape to cover the holes while filling
• A jug of water and a tray or a place outdoors
• A ruler and chalk to mark where each jet lands

Safety: An adult must make the holes with a heated nail or a sharp pin. Do the experiment outdoors or on a tray.

Take it further: Make a second bottle with three holes at the same height round its sides and show that the jets are all equal, so pressure acts equally in all directions at the same depth.

What it shows

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.

You will need

• About ten ice cream sticks (free from a kulfi stall, washed)
• Six to eight rubber bands
• A plastic spoon or a bottle cap as the cup
• Pom-poms, paper balls or balls of foil to launch
• A measuring tape and chalk

Safety: Launch only soft things like paper balls, never stones or hard objects, and never aim at a person or an animal.

Take it further: Launch a pom-pom and a heavier foil ball with the same bend and find out which goes further and why.

What it shows

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.

You will need

• Old thin plastic bags or a cut-open polythene sheet (free)
• Thread or thin string, about 4 pieces of 30 cm per parachute
• A small toy, a bottle cap of coins or a paper cup as the load
• Scissors, tape and a ruler
• A stopwatch and a safe high place like a first-floor balcony with an adult

Safety: Drop only from a balcony or stair with an adult present, never lean over a railing, and keep plastic bags away from young children.

Take it further: Keep the canopy the same and change the load, then draw a graph of fall time against the number of coins.

What it shows

A marble released from high up gains speed as it rolls down, trading height (potential energy) for speed (kinetic energy). It can climb a hill or go round a loop only if it started higher than the top of that hill or loop, and friction steals a little energy all the way.

You will need

• Long strips of cardboard from old cartons, folded into U-shaped channels (free)
• A large cardboard box or a wall to tape the track to
• Marbles
• Masking tape and a stapler
• A ruler or measuring tape
• Paper cups as stands

Safety: An adult must cut the cardboard with a knife; marbles are a choking hazard for young children.

Take it further: Time the marble over a measured straight section with a phone and work out its speed for different starting heights.

What it shows

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.

You will need

• A cardboard carton for the castle and a flat card for the bridge (free)
• Two thread spools or two bottle caps as pulleys
• A pencil as the winding axle and a bottle cap as its handle
• Strong thread, about 1 metre
• Tape, glue and a paper fastener or tape hinge
• Paints or coloured paper

Safety: An adult must cut the gateway and the holes for the axle with a craft knife.

Take it further: Add a counterweight of coins on the back of the axle so the bridge balances and the handle turns with almost no effort.

What it shows

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.

You will need

• A cut-down plastic bottle or a paper cup as the well (free)
• A pencil as the axle and a large bottle cap or a cardboard circle as the wheel or handle
• Two ice cream sticks or a cardboard frame to hold the axle
• String and a small bottle cap as the bucket
• A little water and a tray
• Glue and tape

Safety: An adult must make the holes in the frame; do the water part on a tray.

Take it further: Add a ratchet made from a cardboard toothed wheel and a stick pawl so the bucket does not drop back when you let go.

What it shows

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.

You will need

• An old CD case or a clear plastic sheet, cut into three strips, backed with black paper or black tape to make mirrors (free)
• A chips or cardboard tube
• Coloured beads, broken bangle pieces or bits of coloured plastic
• A piece of clear plastic and a piece of butter paper for the end
• Tape, scissors and black paper

Safety: An adult must cut the plastic strips, which can have sharp edges, and check the edges are taped over; bangle pieces are sharp too.

Take it further: Replace the beads with a clear end and point the kaleidoscope at the world to make patterns from trees and buildings.

What it shows

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.

You will need

• An old CD or a circle of white cardboard (free)
• Paints or sketch pens in seven colours, or coloured paper
• A pencil, a marble or a bottle cap as the spinning axle, or a string through two holes
• A ruler and a protractor to divide the circle
• Glue

Safety: Use a blunt pencil through the disc; an adult should make the holes.

Take it further: Attach the disc to a small motor or an old toy’s wheel to spin it at a steady speed and test different colour sets.

What it shows

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.

You will need

• A sheet of chart paper or a flattened cardboard carton (free)
• A kitchen roll tube or a rolled card for the handle end
• Tape and scissors
• A ticking clock or a phone playing softly as the sound source
• A measuring tape

Safety: Never shout through the megaphone into someone’s ear, and keep the small end clean if it goes near the ear.

Take it further: Make a stethoscope from a funnel and a length of rubber tube and listen to a friend’s heartbeat.