Science projects
Your Science Exhibition Guide
Choose a project, build it, present it and answer the judges with confidence
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Science project idea finder
Find a project by class, subject and type. Every idea explains the science it shows, what you need, how long it takes and how to stay safe, with free ebooks and ready-made kits if you need them. 930 ideas have numbered steps and viva questions on their own page.
Want a complete build with diagrams? 16 free detailed project guides

Idea finder
Choose your class and what interests you, or search for a word such as magnet, solar, heart or robot. Open any card for a summary, or its title for the full page with the science, the steps and the viva questions.
A DC motor is also a generator. When a second motor is turned by the first, its coil spins inside its magnets and produces a voltage that lights an LED, showing that electrical and mechanical energy can be converted in both directions.
Safety: An adult must use the hot glue gun. Keep hair and loose sleeves away from the spinning shafts.
Take it further: Replace the rubber coupling with a bottle-cap pulley and belt so the generator turns faster than the driving motor.
Water conducts electricity only through dissolved ions. Two probes in a liquid feed a tiny current into a transistor, which amplifies it to light an LED. Distilled water gives nothing, tap water a faint glow and salt water a bright one.
Safety: Battery power only. Dry your hands before handling the circuit, and rinse the probes between cups.
Take it further: Add a multimeter in the base lead and record microamperes for each liquid instead of judging brightness by eye.
A continuity tester tells you whether a path conducts: touch its two probes to the ends of a wire, a fuse or a switch and it beeps if current can flow. It is the first tool for finding broken wires and checking which materials conduct.
Safety: Test only unplugged things. Never touch the probes to anything connected to the mains or to a car battery.
Take it further: Add a 1 kΩ resistor across a second pair of sockets and compare how loudly the buzzer sounds through it.
A bent bare wire and a wand loop form a switch that closes whenever your hand shakes and the loop touches the wire. The buzzer and LED make the contact obvious, turning a simple circuit into a game.
Safety: Wire ends are sharp; an adult should bend and tape them. Battery power only.
Take it further: Add a 555 timer that keeps the buzzer sounding for two seconds after a touch so brief touches cannot be hidden.
A DC motor turns electrical energy into rotation. Angled blades cut from a bottle push air backwards as they turn, so a breeze comes forward, and a switch in the circuit starts and stops the fan.
Safety: An adult must cut the bottle and use the hot glue gun. Keep fingers and hair away from the spinning blades.
Take it further: Add a second battery holder and a selector switch so the fan has a slow (3 V) and a fast (4.5 V) setting.
A motor turns a small pulley, a rubber band carries that rotation to a larger roller, and a loop of cloth belt stretched between two rollers moves objects along. It shows belt drives, friction grip and speed reduction through pulley sizes.
Safety: An adult must use the hot glue gun and cut the skewers. Keep fingers out of the rollers while running.
Take it further: Add a paper clip lever switch at the end so an arriving object stops the motor automatically.
A motor winding thread onto a spool converts rotation into lifting. A DPDT slide switch swaps the battery polarity so the same motor raises and lowers the hook, which is how real crane winches are controlled.
Safety: An adult must use the hot glue gun. Do not lift anything heavier than about 100 g or the motor will stall and heat up.
Take it further: Add a paper clip limit switch at the top that opens the circuit when the hook reaches the jib.
An electromagnet pulls a springy steel strip towards it, which breaks its own contact, loses the magnetism and springs back to close the contact again. The strip vibrates to and fro, striking a tin lid to ring like a doorbell.
Safety: An adult must handle the hacksaw blade (tape the teeth) and screws. Run the bell in short bursts; the coil warms up.
Take it further: Replace the push switch with the reed switch door sensor project so the bell rings when a door opens.
Three LEDs each with their own resistor and switch share one battery. Each switch controls only its own branch, which is a parallel circuit, the way the lights in a house are wired so that one can be on while the others are off.
Safety: Battery power only. Scissors and drawing pins with an adult present.
Take it further: Replace the switches with a 555 timer and two transistors to make the lights change by themselves.
A 555 timer in astable mode charges and discharges a capacitor through two resistors, producing a steady stream of pulses. With 1 kΩ, 470 kΩ and 1 µF the output switches about 1.5 times a second, blinking an LED without any switch being pressed.
Safety: Battery power only. Fit the electrolytic capacitor the right way round; its negative lead is marked with a stripe.
Take it further: Replace the 470 kΩ resistor with a 1 MΩ potentiometer and make a blink rate you can adjust with a knob.
Dry skin has a resistance of hundreds of kilohms, far too high to light an LED directly. Two transistors in a Darlington pair multiply the microampere current through a fingertip by about 40,000, so a light touch across two pads switches the LED on.
Safety: A 9 V battery through dry skin is far below any level you can feel; still, keep the circuit away from cuts and wet hands.
Take it further: Swap the LED for a 5 V relay module and let the touch switch a small motor on.
Running a 555 astable fast enough produces audio frequencies. A potentiometer changes the timing resistance, so turning the knob slides the pitch up and down, demonstrating the link between frequency and pitch.
Safety: Battery power only. The sound can be shrill; keep it away from ears and pets.
Take it further: Add a second 555 running at 2 Hz to pin 5 of the first and you have a two-tone siren.
A reed switch closes when a magnet is near and opens when it moves away. With the magnet on the door and the switch on the frame, opening the door removes the magnet, and a transistor circuit turns the buzzer on, the same way shop door sensors work.
Safety: Reed switches are thin glass; bend the leads gently with pliers, never near the glass body. Keep small magnets away from young children.
Take it further: Add a relay latch so the alarm keeps sounding even after the door is pushed shut again.
A magnet on a spoke closes a reed switch on the fork once every turn, flashing an LED. Counting flashes in a known time and knowing the wheel circumference gives the bicycle speed, the same method a bike speedometer uses.
Safety: Test with the bicycle upside down or on a stand, never while riding on the road. Keep hands clear of the spokes.
Take it further: Feed the reed switch pulses into an Arduino and display the speed on a small screen.
An NTC thermistor loses resistance as it warms. In a voltage divider with a potentiometer, warming raises the transistor base voltage until it switches a buzzer on, giving an adjustable temperature alarm like the one in a geyser or a kettle.
Safety: An adult must pour the warm water; use water below 60 °C. Keep the breadboard and battery dry; only the thermistor on long leads goes near the cup.
Take it further: Swap the thermistor and the pot so the circuit sounds when something gets cold, for a fridge door alarm.
With the thermistor placed on the ground side of a voltage divider, cooling raises its resistance and the base voltage, lighting an LED when the air drops below a set temperature. It shows how the same sensor can trigger on cold instead of heat just by swapping its position.
Safety: Battery power only. Keep the thermistor in a dry plastic bag when testing with ice so water never reaches the circuit.
Take it further: Replace the LED with a relay module that switches on a battery lamp over the seedling tray.
A relay module can hold itself on: once its coil is energised, its own contact keeps feeding the coil even after the trigger button is released. This latch is how real alarm panels remember that a sensor tripped, until someone presses reset.
Safety: Battery power only; the relay contacts are rated for mains but you must never connect mains. Check the module label for its coil voltage.
Take it further: Replace the trigger button with the reed switch door sensor so a door opening latches the alarm on.
A small sensor signal can control a bigger load through a relay. The LDR and transistor sense darkness, the relay module switches a separate motor circuit, and the two circuits never share current, which is how electronics controls heavy machinery.
Safety: Battery power only; the relay contacts may be rated for mains but the mains is never used. Keep fingers clear of the propeller.
Take it further: Swap the LDR for the thermistor divider so the fan starts when the room gets hot instead of dark.
A solar cell turns light directly into electrical energy. Connected to a toy motor with a paper disc, it spins in sunlight, slows in shade and stops indoors, showing how output depends on the amount and angle of light.
Safety: Use the cell outdoors in sunlight but do not look at the sun. The motor runs above its rated voltage only briefly in full sun, so stop if it gets warm.
Take it further: Measure the cell voltage with a multimeter at different angles and plot voltage against angle.
The electrical output of a solar cell falls as the light strikes it at a shallower angle, because the same beam is spread over a bigger area. Measuring voltage and current at known tilt angles shows why rooftop panels in India are tilted roughly at the latitude angle.
Safety: Do not look at the sun. Work in the shade of a hat and take breaks; test in the morning or late afternoon rather than at midday in summer.
Take it further: Build a two-position tracker that tilts the cell by hand each hour and compare total output with a fixed cell.
A NodeMCU (ESP8266) joins the home Wi-Fi, runs a tiny web server and turns a relay on or off when a phone browser taps a button. The relay switches a 12 V LED strip, so the whole thing is a low-voltage copy of a smart switch.
Safety: Only the 12 V LED strip goes through the relay. Never connect the relay to a mains wire or socket. An adult must check the wiring before the adapter is plugged in.
Take it further: Add a second relay and a DHT11 so the page also shows room temperature and lets you switch a 12 V fan.
A passive infrared (PIR) sensor detects the heat of a moving person. An Arduino switches a 12 V LED strip on through a relay and keeps it on for a timer period that restarts with every new movement, so the light never cuts out while someone is still walking.
Safety: Low voltage only: the relay switches the 12 V strip, never a mains lamp. An adult must check the adapter connections.
Take it further: Add an LDR so the light only works after dark, and log each trigger time to the serial monitor.
A DHT11 measures temperature and relative humidity, an Arduino calculates a heat index, and a small OLED screen shows the readings with a comfort message. The project shows how a digital sensor sends numbers over one wire.
Safety: USB or battery power only. Keep the OLED glass away from bending.
Take it further: Swap the DHT11 for a DHT22 and compare readings, or log readings to the serial plotter over a whole day.
An MQ-2 gas sensor changes resistance when LPG, butane or smoke touches its heated element. The Arduino compares the reading to a threshold, sounds a buzzer, flashes a red LED and switches a 12 V DC fan through a relay to clear the air.
Safety: Test with a gas lighter held unlit near the sensor for a moment, never with a cylinder valve open. The relay switches only the 12 V fan. An adult must be present for the gas test. The sensor heater gets warm; do not touch it.
Take it further: Replace the Uno with an ESP8266 and send a phone notification through a free IoT app when the alarm triggers.
Before you start
Six things to think about before you decide. A project you understand and finish well beats a big one you rush.
Good projects answer a question you are curious about: why does iron rust, which fabric keeps tea hottest, how does a robot follow a line? A question gives your project a purpose.
Find out whether your teacher wants a working model, a still model or an investigatory project, the size limits, the topic or theme, the date, and whether ready-made models are allowed.
Each idea here shows a class band, a difficulty and a rough time. Choose something you can finish properly with time to test it, rather than something huge you have to rush.
Judges and examiners ask how it works. Choose an idea whose science you understand, or can learn from your textbook and the free ebooks, and practise explaining it.
Write down everything you need before you start. Many models use things from home; motors, LEDs, sensors and boards are easy to buy as spare parts or in a kit.
Change one thing and measure what happens, add a chart of your readings, or show a real-life use. Even a well-known model becomes yours when you add your own observations.
Plan your time
Work backwards from the date of your exhibition or submission. Short of time? Do the same steps faster, but never skip testing.
On the day
You will usually have a minute or two to explain your project, then questions. Practise both out loud at home.
Projects and kits
Need a working model, a kit to build yourself, or a motor, LED, battery or sensor to finish your own? Every idea card links to the matching section of the store.







Cannot find what you need? Ask the head office on WhatsApp.
Free ebooks
Step-by-step project books for every class, plus guides to exhibitions, project files and viva questions. Free to download, read and print.
Science projects
Choose a project, build it, present it and answer the judges with confidence
Science projects
How to write the report, from the cover page to the bibliography
Science projects
How to answer examiner questions, with sample questions for popular projects
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Simple, safe projects young children can make with a little help
Science projects
Working models matched to middle-school science topics
Science projects
Topics, method and report structure for physics, chemistry and biology
Stay safe
Read these with a parent before you start. Ideas that need extra care carry their own safety note on the card.
Power your models with cells, batteries or a low-voltage adapter. Never connect anything home-made to a wall socket.
Cutters, blades, glue guns, soldering irons and drills need an adult beside you. Cut away from your body on a board.
Use only safe household materials at home. Acids, stains and other lab chemicals are for the school lab with your teacher. Wear goggles and never taste anything.
Candles and burners only with an adult present and water nearby. Tie back long hair and keep paper away.
Do not short-circuit a battery, mix old and new cells, or puncture or heat a lithium battery. Remove batteries when the model is stored.
Magnets, button cells and small parts can be swallowed. Keep them away from younger brothers and sisters, and wash your hands after making.
Still have a question?
Chat on WhatsAppA working model moves or works to show a principle, such as a windmill that lights an LED. A still model shows how something is built or arranged, such as the layers of the Earth. An investigatory project asks a question and answers it by experiment: you change one thing, measure the result and draw a conclusion from your readings.
Check your school’s rules first: some competitions want models made by the student, and some allow ready-made ones. Either way, you must understand how it works and be able to explain it. A good approach is to build from a kit, or to add your own measurements and chart to a ready-made model.
Each idea here shows a rough time for the making. Leave extra time for reading, testing, the report and practice: three to four weeks from choosing to presenting is comfortable for most school projects.
A title page, your aim, the science behind it, the materials, the method with a diagram, your observations in a table, the result and conclusion, precautions, and the books and websites you used. The free ebook “Writing a Science Project File” explains each part.
Carry spare cells, wires and tape, and test everything when you arrive. Take a short video or photos of it working at home. If something still fails, explain calmly what should happen and what you would check: judges value understanding as much as a perfect model.
More help
Read the student help pages, try the free calculators for circuits and units, or ask the head office on WhatsApp.