1029 science project ideas, from class 1 to college.

What it shows

Waste plastic can be reused instead of thrown away, and a feeder lets you observe local birds. Keep a diary of which birds visit and when.

You will need

• A clean plastic bottle
• Two wooden spoons or sticks as perches
• String
• Grain such as bajra

Safety: An adult should cut the holes in the bottle.

What it shows

Energy passes from plants to plant-eaters to meat-eaters. Taking one living thing out of the web affects all the others.

You will need

• Pictures or clay models of plants and animals
• Arrows cut from card
• A board

What it shows

Rain falling on a roof is collected by gutters and pipes, filtered, and either stored in a tank or sent down a recharge pit to refill the groundwater.

You will need

• A cardboard house with a sloping roof
• Straws or thin pipes as gutters
• A small container as the storage tank
• A recharge pit of sand and gravel layers in a cup
• A base board

What it shows

Gravel, sand and charcoal trap particles of different sizes, and charcoal also removes some colour and smell. The water looks clearer but is still not safe to drink, because germs pass through.

You will need

• A plastic bottle cut in half
• Cotton wool
• Fine sand, coarse sand and gravel
• Activated charcoal
• Muddy water

Safety: Never drink the filtered water.

What it shows

Black surfaces absorb more sunlight than shiny or white ones, and a clear cover traps the heat, so water in a black, covered container warms fastest.

You will need

• A shoe box lined with foil
• Two small bottles, one painted black and one left clear
• Cling film or a sheet of glass
• A thermometer
• Water

Take it further: Record both temperatures every 15 minutes and plot them on one graph.

What it shows

Plant roots hold soil together. When water is poured on, bare soil washes away much faster than soil covered with grass or dead leaves.

You will need

• Three plastic bottles cut lengthwise
• Soil, grass seedlings and dry leaves
• Three cups to collect the run-off
• Water in a mug

Take it further: Compare how muddy the water in each cup is, and how much soil settles at the bottom.

What it shows

Microbes and small creatures break peels and leaves down into compost, but plastic does not break down. Layers of wet "greens" and dry "browns" rot best.

You will need

• A large plastic bottle with air holes
• Soil
• Vegetable peels and dry leaves
• A small piece of plastic and of paper for comparison
• A water spray

Safety: Wash your hands after handling soil and compost.

What it shows

A covered jar in the sun warms faster than an open one. It is a simple model of how greenhouse gases keep heat near the Earth; the real atmosphere traps heat by absorbing infrared rather than by stopping air moving.

You will need

• Two identical jars
• Two thermometers
• Cling film or a lid
• Sunlight or a lamp
• A notebook for readings

What it shows

Dust and soot in the air settle on surfaces. Sticky cards left in different places show where the air carries the most particles.

You will need

• White cards
• Petroleum jelly
• String
• A magnifying glass
• Labels for each place: roadside, garden, classroom, kitchen

What it shows

Water dripping slowly at the roots reaches the plant with far less waste than flooding, because less water runs off or evaporates.

You will need

• Plastic bottles
• A thin pipe or an old drip set
• A pin to make small holes
• Pots with soil and plants

What it shows

Without air, microbes break down dung and kitchen waste and give off biogas, which is mostly methane. The slurry left behind is good manure.

You will need

• A plastic bottle as the digester
• Cow dung or kitchen waste mixed with water
• A balloon over the mouth to collect the gas
• A model of a dome-type plant to explain the parts

Safety: Biogas burns: never light it. Keep the bottle in an airy place and wash your hands after handling waste.

What it shows

The black inside absorbs sunlight, a mirror reflector sends more light in, and a glass lid traps the heat, so the box gets hot enough to warm food.

You will need

• A cardboard box inside a bigger box
• Newspaper or thermocol insulation between them
• Black paint
• Aluminium foil on a card reflector
• A glass or clear plastic lid
• A thermometer

Safety: The inside gets very hot: handle it with a cloth, and do not look at the reflected sunlight.

What it shows

A TDS sensor estimates dissolved solids from how well the water conducts, a turbidity sensor measures how cloudy it is, and a pH sensor shows its acidity. The readings show whether a source needs treatment, but only a laboratory test can say water is safe to drink.

You will need

• An Arduino or ESP32
• TDS, turbidity and pH sensor modules
• A display or an IoT dashboard
• Water samples and calibration solutions

What it shows

Household waste belongs in different bins: wet kitchen waste for composting, dry recyclables, hazardous items like batteries and medicines, and sanitary waste. Sorting cards into four coloured bins teaches the habit and shows how little should really go to a landfill.

You will need

• Four small boxes painted green, blue, red and yellow
• Forty cards with drawings or cut-out pictures of waste items
• A chart paper for the answer key
• Colours and glue
• A timer

Take it further: Add a fifth e-waste box and find out where in your town old phones and chargers are collected.

What it shows

Natural materials such as peels, paper and cotton are broken down by soil organisms within weeks, while plastic, foil and glass stay unchanged. Burying samples and digging them up shows which waste is biodegradable and which will stay in a dump for centuries.

You will need

• Eight items: an apple peel, a leaf, a piece of newspaper, a cotton rag, a plastic bag piece, a bottle cap, a piece of foil, a polystyrene chip
• A patch of garden soil or a large pot
• Eight ice-cream sticks as labels
• A ruler
• Gloves
• A camera or a sketchbook

Safety: Wear gloves when digging and wash hands afterwards.

Take it further: Bury a "biodegradable" carry bag and check whether it really breaks down in six weeks.

What it shows

Composting worms eat vegetable waste and pass it out as dark, crumbly castings that are a rich plant food. A tub with drainage, bedding and the right moisture turns a family's peels into compost and shows how much kitchen waste never needs to reach a dump.

You will need

• A plastic tub with a lid, about 20 litres, with holes drilled in the sides and base
• Shredded newspaper and dry leaves as bedding
• About 100 composting worms (Eisenia fetida) from a nursery or a farmer
• Kitchen peels without citrus, onion, oil or dairy
• A tray under the tub to catch liquid
• A spray bottle
• A kitchen scale

Safety: An adult should drill the holes. Wash hands after handling the tub, and keep it shaded; worms die above about 35 degrees.

Take it further: Count the worms at the start and after eight weeks to estimate how fast they multiply.

What it shows

Counting and weighing every piece of plastic a family throws away in a week shows where it comes from: packaging of snacks, milk pouches, carry bags and bottles. Sorting it by type and by whether it can be recycled shows which habits would cut the most.

You will need

• A large bag or box to collect the week's plastic
• A kitchen scale
• Gloves
• A tally sheet with columns for item, type, count, weight and recyclable yes or no
• Chart paper and colours for the bar chart

Safety: Wear gloves, rinse food packaging before storing it, and keep sharp or medical plastics out of the collection.

Take it further: Repeat the audit a month after the family tries the two changes and compare the charts.

What it shows

A tap that drips once a second seems harmless, but catching the drips for ten minutes and multiplying up shows it wastes thousands of litres a year, enough to fill a water tanker. Measurement turns a small leak into a number people act on.

You will need

• A measuring cup or a bottle with millilitre marks
• A clock or a stopwatch
• A tap that can be set to drip, or a bottle with a pinhole as a model
• A calculator
• Chart paper

Take it further: Count the dripping taps in your school and estimate the school's total yearly loss.

What it shows

The same task, such as brushing teeth, washing hands or washing a plate, uses many times more water when the tap runs than when water is taken from a mug or bucket. Measuring both ways gives the family hard numbers for saving water.

You will need

• A bucket with litre marks, or a measuring jug
• A mug
• A stopwatch
• A tally sheet with columns for task, method and litres
• A chart paper

Take it further: Measure a bucket bath against a shower and add it to the chart.

What it shows

The water a roof can harvest equals roof area times rainfall times a runoff factor. Measuring a real roof and using the local annual rainfall shows that even a small house in a 800 millimetre rainfall town can collect tens of thousands of litres a year, often more than the family drinks.

You will need

• A measuring tape
• Annual and monthly rainfall figures for your town from the weather office website or a textbook
• A calculator or a spreadsheet
• Graph paper
• A sketch of the house roof
• A rain gauge if one is available

Take it further: Cost a tank of the size you calculated and compare it with buying tanker water for the dry months.

What it shows

Reading the electricity meter daily and logging how long each appliance runs shows which ones use most of the units. In most homes a few items, such as the geyser, air conditioner, old refrigerator and ceiling fans running all day, account for most of the bill, and small changes cut it without any discomfort.

You will need

• Access to the house electricity meter reading (looking only, never opening it)
• The last three electricity bills
• A list of appliances with their rated watts from their labels
• A log sheet with hours of use per day
• A calculator or spreadsheet
• Chart paper

Safety: Read labels and the meter display only. Never open a meter box, switchboard or appliance, and never touch wiring; an adult must be present when reading the meter.

Take it further: Repeat the week after the changes and compare the two pie charts and bills.

What it shows

Three bulbs giving the same brightness draw very different power: about 60 watts for a filament bulb, 14 for a CFL and 9 for an LED. Using the lumens and watts printed on the packs and the price per unit from a bill, a ten-year cost comparison shows the LED is cheapest by far despite its higher price.

You will need

• Packaging or label photos of a filament bulb, a CFL and an LED of similar lumens
• Shop prices for each
• The per-unit rate from an electricity bill
• A calculator or spreadsheet
• Graph paper

Safety: Reading labels only; do not open or test the bulbs. A CFL contains a small amount of mercury and must not be broken.

Take it further: Count the bulbs in your school and estimate the yearly saving from switching all of them to LEDs.

What it shows

Dust and soot from traffic settle on leaves. Pressing clear tape on leaves from different places and sticking it on white paper gives a visible grey patch whose darkness shows how dusty the air is at each spot.

You will need

• Clear cello tape
• White paper or index cards
• A hand lens
• A notebook
• Access to similar plants, such as hibiscus or a hedge, at five places: a busy road, a lane, a park, a school ground and near a construction site

Safety: Stay on the footpath near roads and go with an adult. Do not pick leaves from private gardens without asking.

Take it further: Repeat the test the day after heavy rain and compare.

What it shows

Clean rain is slightly acidic, around pH 5.6, because carbon dioxide dissolves in it. Sulphur and nitrogen oxides from vehicles and industry make it more acidic. Collecting rain in clean containers at three sites and testing with pH paper shows whether local pollution is lowering the pH.

You will need

• Three clean glass jars or bottles, rinsed with distilled water
• Three wide funnels
• Universal indicator pH paper, range 1 to 14, or a pH meter borrowed from school
• Distilled water as a control
• Labels and a notebook

Safety: Do not drink the collected water. Rinse with distilled water, not tap water, which has its own pH.

Take it further: Leave a marble chip in a sample of the most acidic rain for a month and look for changes in its surface.