Try it at home with a grown-up
Science Experiments for Kids
Hands-on experiments with cups, water, paper and other things you already have, each with a version for little kids, for grades 1 to 5 and for grades 6 to 8.
Every experiment here comes from a How Things Work topic, so a child can try it at the kitchen table and then find out why it happens. Each one asks a question, such as which jar stays warm longest or which towel dries first, and children answer it by watching, measuring and comparing, the way scientists do.
Pick the version for the child's age. Little kids get short, hands-on tries; grades 1 to 5 make a fair test and compare results; grades 6 to 8 measure, record and graph. A grown-up stays for every experiment.
Safety first
- A grown-up stays with the child for every experiment.
- Use only the everyday materials the experiment names. Do not swap in cleaners, medicines or anything hot.
- Nothing here is to be eaten or drunk, even when it uses food.
- Use plastic cups, jars and bottles rather than glass.
- Grown-ups do any cutting, and keep small parts away from children under 3.
- Wash hands after touching soil, leaves or anything messy, and wipe up spills so no one slips.
Kitchen chemistry
Mixing, dissolving and changing everyday things from the kitchen.
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Red cabbage color test
Grades 6–8
With a grown-up, make red cabbage indicator and test safe kitchen samples only: lemon juice, vinegar, baking soda in water, soapy water and tap water. Then add vinegar to the baking soda cup one teaspoon at a time, and record the color after each spoonful. How many spoonfuls bring it back to purple? Never test or mix cleaning products.
Why it works: How do acids and bases behave? -
Salt on ice
Grades 6–8
With a grown-up, fill a bowl with crushed ice and measure its temperature with a kitchen thermometer. Stir in several spoonfuls of salt and measure again every minute. How low does it go? Then stand a small sealed bag of fruit juice in the mixture and see if it freezes.
Why it works: Why does salt change how ice melts? -
Oil and water race
Grades 6–8
With a grown-up, make two identical bottles of water and cooking oil. Shake one hard for thirty seconds, so the oil breaks into tiny drops. Just tip the other over twice, so the drops stay big. Time how long each takes to clear. How does drop size change the time, and what does that tell you about why olive paste is mixed slowly?
Why it works: How is olive oil made? -
Make the smallest bubbles
Grades 6–8
With a grown-up, mix one part dish soap with about four parts water in a bowl. Whisk for 30 seconds and measure the height of the foam with a ruler. Repeat with half as much soap, then with a fork instead of a whisk. Which change matters more to the foam: the amount of soap or the tool that cuts in the air?
Why it works: How do foaming soap dispensers make foam? -
Eggshell in vinegar
Grades 6–8
With a grown-up, model growth bands. For each 'year', wrap a layer of modeling clay around a small ball, alternating two colors and using thick layers for good years and thin layers for poor ones. Slice the ball in half with a piece of string and ask a friend to read its history. Then compare eggshell (calcium carbonate) left overnight in vinegar and in water to see how acid attacks limestone.
Why it works: How do coral reefs grow? -
The waterproof wax test
Grades 6–8
With a grown-up, compare drops of water on waxed paper, plain paper, aluminum foil and a paper towel. Sketch the shape of a drop on each from the side: tall beads mean a large contact angle. Then touch a bead on the waxed paper with a toothpick dipped in dish soap and watch what happens. What does that tell you about detergent and water birds?
Why it works: How do ducks keep their feathers water-resistant? -
Banana ripening race
Grades 6–8
With a grown-up, set up three green bananas: one on the counter, one in a paper bag with a ripe apple, and one in a cool place. Each day, rate the color from 1 (green) to 7 (spotted) and note the firmness. Plot your scores against time. Do your curves look S-shaped?
Why it works: How does fruit ripen? -
Sift the flour
Grades 6–8
With a grown-up, sift 100 g of whole-wheat flour through a fine sieve and weigh what passes and what stays. Calculate the percent that passed. Your sieve is acting like a mill's sifter, and your answer is like an extraction rate.
Why it works: How is flour made from wheat? -
Winnow the grain
Grades 6–8
With a grown-up, mix 50 g of rice with light crumbs. Pour the mix slowly onto a tray while your helper fans it with a large piece of cardboard, first gently, then harder. Collect what lands near and far, weigh each pile and work out a 'loss' and a 'dockage' percentage for each fanning strength.
Why it works: How does a combine harvester work?
Hot and cold
How warmth escapes, how to slow it down, and where water drops come from.
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Keep it warm: the wrap test
Grades 6–8
Repeat the jar test with three wraps of the same thickness: bubble wrap, aluminum foil and a wool sock, plus a bare jar. Use warm tap water, not hot. Plot temperature against time for each. Which wrap gives the gentlest slope, and why?
Why it works: How does insulation slow heat loss? -
Dry coat, wet coat
Grades 6–8
With a grown-up, fill three identical jars with warm tap water and measure the starting temperature. Leave one bare, wrap one in a dry woolly sock and one in a wet woolly sock. Measure all three every five minutes for half an hour and plot the cooling curves. Which loses heat fastest? Explain it using trapped air.
Why it works: How does animal fur keep warmth in? -
Make dew on a cold cup
Grades 6–8
With a grown-up, put two dark plates outside on the grass at sunset on a clear evening: one in the open and one under a table or a bush. In the morning, compare how wet they are. Wipe each with a dry tissue and weigh the tissues on a kitchen scale if you have one. Try again on a cloudy night and compare.
Why it works: How does dew appear on grass? -
Which towel dries first?
Grades 6–8
With a grown-up, weigh a small wet cloth on kitchen scales. Hang it up and weigh it every 10 minutes until the reading stops changing. Plot mass against time. Repeat with a fan blowing on it from a safe distance and compare the slopes of the two graphs.
Why it works: How do wet clothes dry? -
Find the warm handprint
Grades 6–8
With a grown-up, fill two identical mugs, one with warm tap water and one with cold. Ask someone to guess which is which without touching, only by holding a hand a few centimeters away. Then try with one mug wrapped in shiny kitchen foil. Is the warm one harder to detect? Foil is a poor emitter of infrared.
Why it works: How do thermal cameras show heat patterns?
Water, weather and Earth
Rivers, floods, waves and the ground under our feet, in a baking tray.
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Gravel or sand: where does water go?
Grades 6–8
Fill a measuring jug to the 500 mL line with dry gravel. With a grown-up, pour in water from a second jug until it just reaches the top of the gravel, and note how much you used. That volume divided by 500 is the porosity. Repeat with sand and compare.
Why it works: How do aquifers store groundwater? -
Towel hill, bare hill
Grades 6–8
With a grown-up, set up three funnels or sieves lined with coffee filters over jars. Fill one with sand, one with garden soil and one with fine clay or flour paste. Pour the same amount of water onto each, time how long the water takes to drip through, and measure how much each one keeps.
Why it works: How do floods develop? -
Sand or clay: which drains faster?
Grades 6–8
With a grown-up, dig a hole about 15 cm deep in a garden bed. Fill it with water and let it drain once. Fill it again, stand a ruler in it and note the water level every 15 minutes. Work out the infiltration rate in millimeters per hour. Compare a spot in the lawn with a spot people often walk on.
Why it works: How do rain gardens reduce runoff? -
A river in a tray
Grades 6–8
Build a stream table with a grown-up (a tray of damp sand and a cup with a small hole for a steady flow). Measure the slope, run each test for the same time and photograph the channel. Estimate sinuosity with a piece of string, then compare slopes.
Why it works: How do rivers shape the land? -
A beach in a baking tray
Grades 6–8
Build the tray model, then test a groyne: stand a row of small stones or a strip of card across the beach. Make 50 slanted waves and sketch the shoreline before and after. Which side grew? Repeat with the waves coming from the other side.
Why it works: How do waves change coastlines? -
Waves from deep to shallow
Grades 6–8
With a grown-up, fill a long, shallow tray with 1 centimeter of water. Lift and drop one end slightly and time the wave to the far end. Repeat with 2 and 4 centimeters. The speed should grow with the square root of the depth: does doubling the depth make the wave about 1.4 times faster?
Why it works: How do ocean waves form and reach the shore? -
A whirlpool in a jar
Grades 6–8
Make a jar vortex with a grown-up (water, a drop of dish soap, tightly closed lid). Swirl it fast and slow and compare the vortex. Then look up your local weather service's watch and warning alerts and write a family plan: where you would shelter and how you would get warnings.
Why it works: How do tornadoes form? -
Clear the muddy water
Grades 6–8
Shake soil into two jars of water. With a grown-up, stir a pinch of alum (sold for pickling) into one jar for a minute. Time how long each jar takes to clear and compare the sediment. Never drink your test water.
Why it works: How does clean water reach our taps? -
Where does the spring come out?
Grades 6–8
With a grown-up, build the same model with two tilted sheets: a short one high up and a longer one below, sloping the other way. Predict where the 'spring' will be, then add water with a watering can and time how long it takes to appear. Does it keep dripping after you stop pouring?
Why it works: How do natural springs bring water to the surface?
Forces and simple machines
Pushes, pulls, levers, wedges and things that swing, bounce and float.
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Make water climb with a straw
Grades 6–8
With a grown-up, siphon water between two clear containers using a tube filled at the tap. Mark the levels every 30 seconds. Does the level change more slowly as the surfaces get closer? Plot the level difference against time.
Why it works: How does a siphon move water between containers? -
The straw that holds water
Grades 6–8
With a grown-up, fill a tall clear bottle with water, cover the top, turn it upside down in a bowl of water and uncover it. The water stays up in the bottle. What is holding it? Work out how tall a bottle would have to be before the water came down.
Why it works: How does a hand pump raise water? -
Long swing, short swing
Grades 6–8
Make a string pendulum with a grown-up. Time 10 full swings for lengths of 25 cm, 50 cm and 100 cm, divide by 10 to get the period, and compare with T = 2π√(L/g). Plot T against √L. Is it a straight line?
Why it works: How does a pendulum clock keep time? -
Bounce in water
Grades 6–8
With a grown-up, hang a weight from a rubber band or a spring. Time ten bobs in air, then count how many bobs it takes to stop in water and in cooking oil. Which liquid gives the most damping, and how does that link to a shock absorber's oil?
Why it works: How do shock absorbers reduce bouncing? -
Thin wedge, fat wedge
Grades 6–8
With a grown-up, cut three cardboard wedges with the same length but different thicknesses. Push each between two heavy books and measure how far the wedge goes in and how far the books move apart. Divide the first by the second: that is the wedge's mechanical advantage. Compare it with length ÷ thickness.
Why it works: How do wedges split or separate materials? -
Squeeze near the hinge
Grades 6–8
With a grown-up, measure a pair of pliers or kitchen tongs: from the pivot to where your hand pushes, and from the pivot to where the jaws grip. Work out the mechanical advantage at the tips and near the pivot. Only handle tools with a grown-up, and keep fingers out of the jaws.
Why it works: How do pliers grip objects firmly? -
Which wall is stronger?
Grades 6–8
With a grown-up, build a running-bond wall of toy bricks on a kitchen scale and press one top brick with a known force. Then build it in stack bond on the scale and compare where it separates. Sketch how the load spreads.
Why it works: How are bricks made? -
Shake the towers
Grades 6–8
With a grown-up, make a shake table from a baking tray on two round pencils. Build towers of different heights from craft sticks and clay, and slide the tray at slow and fast rhythms. Which towers sway most at which rhythm? Try adding braces or a sponge base.
Why it works: How do earthquakes happen? -
Spread the weight
Grades 6–8
Ask a grown-up to help you weigh yourself, then trace both your feet on squared paper and count the squares to find the area. Divide your weight in newtons (kilograms times 9.8) by the area in square meters. That is your ground pressure when standing. What is it when you stand on one foot?
Why it works: How do tracked vehicles cross soft ground? -
Flat or edge first?
Grades 6–8
Drop a flat coffee filter and one crumpled into a ball from the same height, and time them. The flat one has more drag. Then stack two or three flat filters and time them again: how does extra mass change the fall?
Why it works: How do spacecraft return through the atmosphere? -
How much air is in the trash?
Grades 6–8
Measure a compaction ratio. Fill a straight-sided container with crumpled paper and measure the height. Press a flat lid down firmly and measure again. Ratio = height before divided by height after. Repeat with foil balls and with dry leaves. Which has the most air?
Why it works: How do garbage trucks collect and compact waste?
Living things and your body
Watch fallen leaves break down, and test your own fingerprints, muscles and memory.
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Fingerprint detective
Grades 6–8
With a grown-up, make pencil-and-tape prints of all ten fingers, and ask family members to do the same. Classify each print as an arch, loop or whorl, count its deltas, and make a chart. Is one family of pattern common in your family? Then find two loops and spot three details that differ.
Why it works: How do fingerprints form? -
Cram or practice a little each day?
Grades 6–8
Make two sets of ten flash cards with new words or facts. Study set A in one 15-minute session. Study set B for five minutes on each of three days. Test both sets after one week and again after two. Plot the scores and compare the forgetting.
Why it works: How does the brain form memories? -
Feel your muscles work
Grades 6–8
With a grown-up, hold a light bag of rice with your elbow at 90°. Measure your forearm from the elbow to the bag and estimate the biceps lever arm as about 4 cm. Use moments (force × distance) to estimate the biceps force.
Why it works: How do bones, muscles, and joints help us move? -
The fallen leaf race
Grades 6–8
With a grown-up, weigh three equal batches of dry fallen leaves and seal each in a mesh bag. Place one on damp soil under leaves, one on dry gravel in the open, and keep one dry indoors. After six weeks, dry the leaves again indoors and reweigh them. Work out the percentage of mass lost in each place and explain the differences. Wash your hands after handling leaves and soil.
Why it works: How do decomposers break down fallen leaves?
Light, sound and materials
Shadows, notes from bottles, and what pencils and crayons are made of.
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Bottle music
Grades 6–8
Cut five drinking straws to lengths of 20, 16, 12, 10 and 8 centimeters (ask a grown-up to help with the scissors). Pinch one end shut, hold the open end against your lower lip and blow across it. Work out the note each should play, using speed of sound divided by four times the length for a tube closed at one end, and compare by ear.
Why it works: How do flutes produce different notes? -
Shadow sorting
Grades 6–8
Test how thickness changes what gets through. Shine a flashlight through one sheet of white paper onto a wall, then through 2, 4 and 8 sheets, and judge the brightness of the spot each time. Does each added sheet remove the same amount of light, or the same fraction of what is left? Compare your results with the exponential rule for X-rays.
Why it works: How do X-ray machines look inside objects? -
Day and night with a flashlight
Grades 6–8
Choose five cities on different continents. Look up each one's longitude and its UTC offset and plot offset against longitude. Draw the line of one hour per 15 degrees. Which cities are farthest from the line, and why might their countries have chosen that time?
Why it works: How do time zones work? -
Crayon color mixing
Grades 6–8
Put one crayon in the fridge for an hour and keep an identical crayon at room temperature. Draw a line with each, pressing the same way. Which leaves more wax on the paper, and why might temperature matter? Then layer colors to test subtractive mixing.
Why it works: How are crayons made? -
Which pencil is darkest?
Grades 6–8
Shade three equal boxes with the same pencil, pressing lightly, medium and hard. Compare their darkness, then draw a long line and see how the tip widens. With a grown-up, look at a pencil's end: can you find the glue line between the two wood halves?
Why it works: How are pencils made? -
Measure one sheet of paper
Grades 6–8
Find a long bolt and nut with a grown-up. Mark the nut, turn it exactly ten times and measure how far it moved with a ruler. Divide by ten to find the pitch. How many marks around the nut would you need to read 0.05 millimeters?
Why it works: How does a micrometer measure tiny differences?