1028 science project ideas, from class 1 to college.

What it shows

The air you breathe out can be measured by the water it pushes out of an upturned bottle. It gives your tidal volume and your vital capacity, and shows how they compare between people.

You will need

• A 2 litre clear plastic bottle with a marked scale you make by pouring in known volumes
• A large basin or tub
• About 1 metre of clean plastic tubing
• A permanent marker and a measuring jug
• A fresh disposable straw cut to length, one for each person
• Soapy water and a clean cloth
• A notebook

Safety: Use a fresh straw for every person and wash the tube end with soapy water between users. Do not test anyone with asthma, a cold or breathing trouble. Stop at once if anyone feels dizzy; an adult must supervise.

Take it further: Compare vital capacity before and after four weeks of daily breathing and stretching exercise among willing volunteers.

What it shows

Muscles in exercise need more oxygen and glucose, so the heart beats faster. The time that the pulse takes to come back to normal shows how quickly the body recovers.

You will need

• A watch or phone stopwatch
• A chair and a clear space for stepping on and off a low step 20 cm high
• A notebook and graph paper
• A friend to record the times
• Water for drinking after the test
• A pencil

Safety: Take part only if you are well, and skip the exercise if you have any heart, breathing or health condition. Stop if you feel dizzy, and have an adult supervise at all times.

Take it further: Test how the pulse rises after different amounts of exercise, such as 30 seconds, 1 minute and 2 minutes of stepping, on different days.

What it shows

The kidney filters blood: small molecules such as water, salt and sugar pass out, while blood cells and large proteins are held back. A layered funnel shows the filtering idea step by step.

You will need

• A plastic funnel or the cut top of a bottle
• A tea strainer or kitchen sieve
• A piece of clean muslin or cotton cloth
• A beaker or jar to collect the filtrate
• A mixture: water, a pinch of salt, a spoon of sugar, a few drops of food colour, 20 red beads and a teaspoon of fine soil
• A card for the nephron diagram
• Markers and glue

Safety: An adult must cut the bottle. Do not drink anything from the model; wash hands after handling soil.

Take it further: Add a second jar of clean water and use a sponge to model how water and sugar are taken back from the filtrate.

What it shows

Veins have valves that let blood flow only towards the heart. A tube with a one-way valve and a squeezing hand shows how muscles help push blood back up the legs.

You will need

• About 60 cm of soft clear plastic tube (aquarium air tube)
• A small aquarium one-way (non-return) valve
• Two small jars or cups
• Water with red food colour
• A piece of stiff card to hold the tube
• A plastic bottle, cut, to hold the water
• A towel

Safety: Keep the model away from electrical items and sit it on a tray or in a basin. An adult must help with cutting the tube.

Take it further: Fit a second valve and a second squeeze point to make a two-stage pump and compare the volume moved per ten squeezes.

What it shows

The inside of the small intestine is covered with finger-like villi that give it a very large surface area for absorbing food. A looped towel soaks up much more water than a flat cloth of the same size, just as a villus-lined gut absorbs more.

You will need

• A flat piece of cotton cloth, 10 cm by 10 cm
• A piece of terry towel, 10 cm by 10 cm
• Water with a few drops of food colour
• A kitchen scale that reads to 0.1 g
• A shallow dish
• A timer
• A notebook
• String or a long cloth strip for the small intestine length model

Safety: An adult must cut the cloth and supervise the scissors. Keep the scale dry.

Take it further: Measure the length of the wrinkles in a folded cloth against a flat cloth to calculate how folding increases the area.

What it shows

Foods that contain fat leave a see-through greasy mark on brown paper that does not dry away. A quick rub test sorts foods into those with fat and those without.

You will need

• A sheet of plain brown paper or a paper bag cut into squares
• Food samples: sesame seeds, a potato chip, a piece of apple, a biscuit, a few drops of oil or ghee and a boiled sweet
• A little plain water as a control
• A pencil to label
• A mortar or a spoon to crush seeds
• A window or a lamp
• A notebook

Safety: Check that no one has a nut or seed allergy before using any nuts. Wash hands afterwards. An adult must supervise.

Take it further: Rub equal-sized pieces of different chips and compare the size of the grease spots to rank which has the most fat.

What it shows

Yeast makes dough rise by fermenting sugar and giving off carbon dioxide. Adding more salt to the dough slows the yeast, so the dough rises less.

You will need

• 4 equal clear tall glasses or cut bottles
• Plain flour (maida or atta), 200 g
• Dry baker’s yeast, 4 small pinches
• Sugar, 4 level teaspoons
• Salt, in measured amounts of 0 g, 0.5 g, 1 g and 2 g
• Warm water (about 30 to 35 degrees Celsius), 120 mL
• A ruler and rubber bands to mark height
• A kitchen scale

Safety: An adult must warm the water, because it must not be hot. Do not eat the raw dough. Wash hands and surfaces after handling it.

Take it further: Keep the salt fixed and repeat with different amounts of sugar to see where the rise is the greatest.

What it shows

Ripening fruits release a gas called ethylene that makes nearby fruit ripen faster. Green bananas sealed with a ripe fruit ripen sooner than bananas left on their own.

You will need

• 6 green bananas of the same bunch (or small raw mangoes)
• 1 ripe banana or apple
• Three paper bags or loosely tied plastic bags
• A marker and labels
• A colour chart of 1 to 7 stages (green to brown speckled), which you draw
• A notebook
• A camera or phone for daily photos

Safety: Wash hands after handling fruit. Do not eat any fruit that smells fermented or has gone mouldy; ask an adult to throw it away.

Take it further: Compare ripening in a refrigerator and at room temperature, and record how cold changes the speed.

What it shows

Rice and urad dal batter swells and turns sour overnight because tiny microbes in it make gas and acid. The rise is faster in a warm place than in a cool one.

You will need

• Fresh idli or dosa batter, ground by an adult at home (about 1 cup)
• Two identical tall clear jars or steel vessels with lids
• A ruler and a rubber band to mark the level
• A kitchen thermometer (non-mercury)
• A warm spot (near a cooker) and a cooler spot (floor of a cool room)
• A notebook for the diary

Safety: An adult must grind the batter and handle any hot cooking area. Do not taste the batter if it smells bad or has pink or black patches; throw it away. Wash hands and jars after the test.

Take it further: Find out how the batter rises with a pinch of salt added, and check whether salt makes it slower or faster.

What it shows

Milk turns into curd because friendly bacteria in a spoon of old curd turn milk sugar into lactic acid. Keeping the milk at different temperatures shows how heat changes the speed of this change.

You will need

• Half a litre of milk, boiled by an adult and cooled
• A teaspoon of fresh curd as a starter for each jar (3 teaspoons in all)
• Three clean small steel vessels or glass jars with lids
• A thermometer (non-mercury)
• A warm insulated box or a pot with a towel
• A refrigerator or a cooler corner
• A watch and a notebook

Safety: An adult must boil the milk and pour it. Check that the milk feels only lukewarm on your wrist. Use clean spoons and jars, and throw away milk that smells bad. Wash hands.

Take it further: Compare the setting time with different amounts of starter (half a teaspoon, one and two) in the same warm place.

What it shows

A sealed jar with soil and plants keeps its own small water cycle. Water evaporates from the soil and leaves, condenses on the glass and runs back, while plants and soil life swap oxygen and carbon dioxide.

You will need

• A large clear glass jar or a 2 litre plastic bottle with a wide cut opening, with a lid or cling film
• A handful of small pebbles
• Crushed charcoal (a few pieces)
• Garden soil or potting mix
• Two or three small plants, such as a money plant cutting, a small fern or moss
• A spoon, a long stick to place plants
• A spray bottle of water

Safety: An adult must cut the bottle. Wash your hands after handling soil. Do not place the jar in strong direct sun, where it can overheat and cook the plants.

Take it further: Make a second jar without charcoal or pebbles and compare how the plants fare after a month.

What it shows

Many flowers depend on insects, birds or bats to move pollen so they can make fruit. Counting visitors on two kinds of flower at different times of day shows which flowers and hours are busiest.

You will need

• Two flowering plants of different colours in a garden or a park, for example a yellow marigold and a pink balsam
• A notebook and a pencil
• A phone timer or a watch
• A pre-ruled tally sheet
• A hat and a plastic stool
• A camera (optional)

Safety: Stay a metre away and never touch, catch or disturb the insects, because bees and wasps can sting. Do not do this if you have a bee-sting allergy. Tell an adult where you are and sit quietly.

Take it further: Compare a patch with a nearby building or pesticide-free corner to see whether surrounding conditions change the number of visitors.

What it shows

Microbes in a compost heap give off heat as they break down waste. A balanced mix of green and brown material, kept moist and aerated, warms up more than green waste alone.

You will need

• Two 10 litre buckets with holes drilled in the sides and the bottom
• Green waste: vegetable and fruit peels, tea leaves (no meat, dairy or cooked food)
• Brown waste: dry leaves, paper torn small, coir
• A thermometer reading to 0.5 degrees Celsius (non-mercury)
• A garden trowel and gloves
• A spray bottle for water
• A notebook

Safety: An adult must drill the holes. Wear gloves and wash hands after handling compost, and wear a mask when turning dry, dusty material. Keep the buckets away from food. Do not add meat, dairy or pet waste.

Take it further: Repeat with different ratios of brown to green, such as 1:1, 2:1 and 3:1, and find which gives the greatest rise.

What it shows

Fallen leaves are broken down by fungi, bacteria and soil animals. Burying equal weights of different leaves in mesh bags and weighing them later shows which kinds decompose faster.

You will need

• Dry fallen leaves of four kinds, for example neem, mango, banyan and teak, or any that you can find
• Four to eight small mesh bags (onion bags or net cloth) about 10 cm by 10 cm
• A scale reading to 0.1 g
• A garden trowel and gloves
• Waterproof labels or plastic tags and string
• A garden bed or large pot of soil
• A notebook

Safety: Wear gloves and wash hands after handling soil and leaves. An adult must supervise the digging if you use tools.

Take it further: Bury another set in a dry sandy soil and compare the loss to the moist garden bed.

What it shows

The roots of pulse plants such as gram, pea and groundnut carry small lumps called nodules in which bacteria fix nitrogen from the air. That is why pulses are rotated with cereals to keep soil fertile.

You will need

• A whole gram, pea, groundnut or moong plant with its roots (with the owner’s permission)
• A wheat or grass plant for comparison
• A trowel and a bucket of water
• A hand lens or a magnifying glass
• A sheet of white paper
• A sharp knife for the adult only
• A notebook and coloured pencils

Safety: Take plants only with permission, dig carefully, and wash your hands afterwards. An adult must slice any nodule with the knife.

Take it further: Compare nodule number on plants from a fertiliser-rich bed and a poor bed, and discuss what you see.

What it shows

The thin skin of an onion layer is a sheet of box-like plant cells. A stained slide under the microscope shows the cell wall and the nucleus, and a simple trick lets you estimate how big each cell is.

You will need

• An onion
• A school compound microscope
• Glass slides and cover slips
• Tweezers, a dropper and a blotting paper
• Dilute iodine solution (a few drops of tincture of iodine in a cup of water) or a drop of red ink in water
• A transparent ruler marked in millimetres
• A pencil and a notebook

Safety: An adult must cut the onion, prepare the dilute iodine and supervise. Iodine stains skin and clothes and must not be swallowed; keep it away from eyes. Glass slides break easily. Wash hands after the practical.

Take it further: Compare onion cells with a thin leaf peel from a plant such as Rhoeo and note the difference, such as green chloroplasts.

What it shows

Living cells make an enzyme, catalase, that breaks hydrogen peroxide into water and oxygen. Raw potato foams strongly when added to dilute peroxide, boiled potato hardly foams, and crushed potato foams fastest.

You will need

• One raw potato
• A pan of boiling water (for the adult)
• 3 percent hydrogen peroxide solution from a pharmacy (about 100 mL)
• 4 tall narrow glasses or measuring cylinders
• A few drops of dish soap
• A grater and a knife
• A ruler and a timer
• Goggles and gloves

Safety: Three percent hydrogen peroxide can irritate skin and eyes. An adult must handle and measure it; wear goggles and gloves, never taste it, wash splashes with plenty of water and pour leftovers down the sink. An adult must cut the potato and boil the water.

Take it further: Test the foam from potato pieces kept in ice water, at room temperature and in warm water at 40 degrees Celsius.

What it shows

Fresh pineapple contains bromelain, an enzyme that breaks down proteins, so it stops gelatin jelly from setting. Tinned or boiled pineapple, whose enzyme has been destroyed by heat, lets the jelly set normally.

You will need

• Gelatin powder (enough for 4 small portions; check the pack for the ratio)
• Fresh pineapple, tinned pineapple and a few pieces of fresh pineapple boiled for 5 minutes
• Four small clear cups
• Hot water (an adult must prepare it)
• A refrigerator
• A spoon, a marker and labels
• A notebook

Safety: An adult must handle the hot water. Fresh pineapple can sting the lips and tongue, so do not taste it in quantity. Gelatin is made from animal protein, so check whether the family avoids it. Do not eat the experiment jellies.

Take it further: Use agar instead of gelatin, which is not a protein, and see whether fresh pineapple affects the setting.

What it shows

When two hybrid tall pea plants are crossed, each offspring gets one gene copy from each parent at random. Tossing two coins 100 times copies this and shows the 1 to 2 to 1 genotype and 3 to 1 appearance ratios.

You will need

• Two coins of the same kind
• A table to record the tosses
• A pen or pencil
• A calculator
• Graph paper
• A group of classmates to pool results
• A chart of the cross written as a Punnett square

Take it further: Use two pairs of coins of different kinds for two traits, such as seed shape and colour, and find the 9 to 3 to 3 to 1 ratio for a dihybrid cross.