1029 science project ideas, from class 1 to college.

What it shows

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.

You will need

• Four 1N4007 diodes
• An enclosed, ready-made low-voltage step-down transformer or a low-voltage AC supply
• An electrolytic capacitor and a load resistor or LED
• A breadboard and a multimeter

Safety: Never wire or touch the mains side yourself: use an enclosed transformer or a low-voltage AC supply from your teacher.

What it shows

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.

You will need

• Diodes, resistors and a BC547 transistor
• Two switches and LEDs
• A 5 V supply or battery pack
• A breadboard

What it shows

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.

You will need

• A strong neodymium magnet
• A copper or aluminium pipe
• A non-magnetic object of similar size for comparison
• A stopwatch

Safety: Neodymium magnets snap together and can pinch. Keep them away from phones, pacemakers and young children.

Take it further: Time the fall through pipes of different thickness or length.

What it shows

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.

You will need

• A tall clear glass or beaker
• A coin and a scale
• Water, glycerine and cooking oil
• A travelling microscope in the lab, or pins and careful sighting

What it shows

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.

You will need

• A 30 cm plastic or wooden ruler
• A pencil, a cotton reel or a bottle cap as the pivot
• Ten identical coins (all one rupee, for example)
• A pencil and a notebook for the table

Take it further: Replace the coins with small objects of unknown weight and use the balance rule to work out how many coins each one weighs.

What it shows

An inclined plane lets you move a load up with less force than lifting it straight, but over a longer distance. The gentler the slope, the smaller the pull needed and the longer the path.

You will need

• A stiff cardboard sheet or a wooden plank about 60 cm long
• A pile of books to raise one end
• A small toy car or a matchbox with a pebble in it
• A rubber band and a paper clip as the force meter
• A ruler and a strip of paper to record the stretch

Take it further: Cover the ramp with a cloth and then with a smooth plastic sheet and see how friction changes the force needed.

What it shows

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.

You will need

• A straight stick or pencil about 30 cm long
• A sheet of chart paper and stones to hold it down
• A marker pen and a ruler
• A clock or a phone to note the time
• A sunny open spot such as a terrace or courtyard

Safety: Never look straight at the Sun, and work in the shade yourself between readings during the hottest hours.

Take it further: Measure the midday shadow once a month for a few months and see how it changes between winter and summer.

What it shows

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.

You will need

• Six identical glass bottles or glasses
• Water and a jug
• Food colour to make the levels easy to see
• A metal spoon or a pencil to tap with
• A ruler to measure the water height

Safety: Tap glass gently; an adult must clear up if any bottle breaks.

Take it further: Use a free tuner app on a phone to find the frequency of each bottle and plot it against water height.

What it shows

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.

You will need

• A lump of modelling clay or plasticine about the size of a lemon
• A tub or bucket of water
• A handful of coins or marbles as cargo
• A ruler
• A towel for spills

Take it further: Float the bowl in salt water and in fresh water and compare how many coins it holds in each.

What it shows

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.

You will need

• A fresh raw egg
• A tall glass or a clear jar
• Table salt and a teaspoon
• Water
• A spoon for stirring and a notebook

Safety: Wash hands after handling a raw egg, and do not eat the egg after the experiment.

Take it further: Test an old egg and a fresh egg in plain water; an old egg has a bigger air pocket and may float, which is a simple freshness test.

What it shows

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.

You will need

• Two identical plastic bottles (free)
• Two balloons
• A pin or a hot nail to make a small hole, used by an adult
• Tape

Safety: An adult must make the hole with a heated nail or a drill. Blow gently so the balloon does not pop near your face.

Take it further: Fit a straw through the bottle lid next to the balloon neck and use it as a hand pump to blow the balloon up and let it down.

What it shows

A capped bottle of warm air shrinks and crumples when it is cooled quickly, because the cooled air inside takes up less space and presses less, while the air outside keeps pressing in. It shows that air pressure is a real and strong push.

You will need

• An empty thin plastic water bottle with its cap (free)
• Warm tap water, not boiling
• A bowl of cold water with ice cubes
• A towel and a tray

Safety: Use only warm tap water from the hot tap, never boiling water, and an adult must handle the warm water for younger students.

Take it further: Repeat with an empty aluminium drink can and warm water, and compare how strongly it dents.

What it shows

The time for one swing of a pendulum depends on its length, not on how heavy the bob is or how wide it swings (for small swings). A longer pendulum swings more slowly. Pendulum clocks are built on this rule.

You will need

• About 1.5 metres of strong thread
• A heavy nut, a stone or a bunch of keys as the bob
• A second, heavier bob such as two nuts
• A ruler or measuring tape
• A stopwatch or a phone timer
• A table edge or a doorframe to hang from, and tape

Safety: Hang the bob where it cannot hit anyone, and keep small nuts away from young children.

Take it further: Make the length four times longer and show that the swing time only doubles, which is the square-root rule.

What it shows

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.

You will need

• A wooden plank or a stiff board about 1 metre long
• Three or four shoes or slippers with different soles (rubber, plastic, cloth, leather)
• A pile of books or bricks to raise one end
• A ruler to measure the height of the raised end
• A protractor if available, and a notebook

Safety: Stack the books so the board cannot slip off; an adult should steady a heavy plank.

Take it further: Repeat with the same shoe on different floors: tiles, cement, cloth and a plastic sheet.

What it shows

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.

You will need

• A fridge magnet or a bar magnet
• A steel paper clip and a short piece of thread
• Sheets of paper, a cotton cloth, a plastic lid, a glass, a thin wooden board, a steel plate
• A glass of water
• A ruler

Safety: Keep small magnets and paper clips away from very young children, and never put magnets near a phone or a bank card.

Take it further: Make a magnet maze: draw a path on a paper plate and guide the clip along it from underneath with the magnet.