Your kitchen is secretly a laboratory. The cupboards are full of chemicals with friendly names like vinegar, bicarbonate of soda and salt, and the fridge is basically a freezing chamber. With a tray, a few jars and a curious mind, you can make things fizz, swirl, float and grow before tea is even on the table.
These experiments are quick to set up, cheap to run and easy to clear away. Each one comes with a bit of the science behind it, so your young boffin learns why it happens as well as enjoying the mess. Some steps need a grown-up, and we have flagged those clearly. Lab coats optional, old T-shirts strongly recommended.
Setting Up Your Lab (Results May Vary, Mess Will Not)
Pick a wipeable surface, ideally a big baking tray or a washing-up bowl on the kitchen table, so spills stay put. Gather your ingredients before you start, because a scientist hunting for the vinegar mid-eruption is a scientist about to knock something over.
Keep experiment cups and spoons separate from the ones you eat with, or wash them well afterwards. Make it clear from the start that nothing in the lab gets tasted unless a grown-up says it is food.
- A tray or washing-up bowl to catch spills
- Clear plastic cups or clean jam jars
- Teaspoons, a jug and some kitchen roll
- An old T-shirt or apron for each scientist
- A notebook for predictions and results
Lay an old tea towel under the tray and clearing up becomes a one-scrunch job.
Think Like a Scientist: Make a Hypothe-guess
Before each experiment, ask your child what they think will happen and write it down. A hypothesis is just a sensible guess, and being wrong is half the fun. Afterwards, talk about what actually happened and why.
Older children can try a fair test: change only one thing at a time. If you are racing ice cubes, use cubes the same size and only change what you sprinkle on them. That one idea is the backbone of real science, and it is never too early to learn it.
Ask 'what would happen if...?' at the end of every experiment and you have your next one sorted.
Why It Works: The Science in a Nutshell (or a Jam Jar)
Most of these experiments rely on a few big ideas. Bicarbonate of soda and vinegar react to make carbon dioxide gas, which is what makes the foam. Bubbles of the same gas cling to raisins in fizzy water and lift them up. Washing-up liquid breaks the surface of milk and chases the fat around, which drags the colours with it.
Lemon juice weakens paper slightly, so the written bits brown faster when gently heated. Salt lowers the temperature at which ice melts, which is why gritters salt the roads in winter. Cress shows how seeds need water, warmth and light to grow.
Clean-Up Time: Don't Let Good Science Go Down the Drain
Most kitchen experiments can be poured away down the sink with plenty of water. Rainbow milk and volcano gloop should go straight down the drain rather than being saved, as nobody wants to find a sour cup of science behind the bread bin next week.
Make tidying part of the experiment: real scientists clean their kit so the next test is fair. Finish with a good handwash for everyone, especially after anything involving raw eggs or vinegar.
Give each scientist a job title for clear-up: Chief Wiper, Head of Cups and Director of Drying.
Ideas to try
Bicarb Volcano
Build a mini volcano and watch it erupt with foamy lava.
You'll need: small plastic bottle or cup, bicarbonate of soda, vinegar, washing-up liquid, red food colouring, tray
- Stand the bottle on a tray and mould play dough or scrunched foil around it into a volcano shape.
- Add two teaspoons of bicarbonate of soda, a squirt of washing-up liquid and a few drops of food colouring.
- Pour in a splash of vinegar and stand back.
- Top up with more bicarb and vinegar for repeat eruptions.
- Never put a lid on the bottle once the mixture is inside.
Dancing Raisins
Raisins rise and sink in fizzy water like tiny disco dancers.
You'll need: tall clear glass, fizzy water or lemonade, a handful of raisins
- Fill a tall glass with freshly opened fizzy water.
- Drop in five or six raisins.
- Watch them sink, collect bubbles and float to the top.
- Count how many times one raisin goes up and down.
- Try the same with plain tap water and compare.
Rainbow Milk Swirl
Make colours burst and swirl across a plate of milk with one touch.
You'll need: shallow plate, full-fat milk, food colouring, cotton bud, washing-up liquid
- Pour enough milk to cover the bottom of the plate.
- Add a few drops of different food colouring near the middle.
- Dip a cotton bud in washing-up liquid.
- Touch it gently to the centre of the milk and hold it still.
- Watch the colours rush away, then pour the milk away afterwards rather than drinking it.
Lemon Secret Agent Ink
Write invisible messages in lemon juice that appear when a grown-up gently heats them.
You'll need: lemon juice, small bowl, cotton buds or a paintbrush, plain white paper, an iron (grown-up only)
- Squeeze some lemon juice into a small bowl.
- Dip a cotton bud and write or draw a secret message.
- Leave the paper to dry completely until the message vanishes.
- A grown-up irons the paper on a medium setting with no steam, over a tea towel, until the writing turns brown.
- Keep the hot iron well away from children and let the paper cool before handing it back.
🧑 Grown-up help needed
Cress Egghead Gang
Grow a crop of cress hair on a smiley eggshell face in about a week.
You'll need: empty eggshells, rinsed, egg box, cotton wool, cress seeds, felt-tip pens
- Rinse the eggshell halves well and wash hands after handling raw egg.
- Draw a face on each shell and stand it in an egg box.
- Fill with damp cotton wool and sprinkle cress seeds on top.
- Put them on a light windowsill and keep the cotton wool damp.
- Give your eggheads a haircut with scissors in about a week.
Great Ice Melting Race
Find out what melts ice fastest: salt, sugar, warm water or nothing at all.
You'll need: ice cubes the same size, four saucers, salt, sugar, a little warm water, timer
- Put one ice cube on each saucer.
- Sprinkle salt on one, sugar on another, drip warm tap water on the third and leave the last alone.
- Ask everyone to predict the winner.
- Check every five minutes and note which is shrinking fastest.
- Don't hold salted ice in your hand, as it gets colder than normal ice.
Walking Water Rainbow
Watch coloured water climb up kitchen roll and mix into new colours.
You'll need: six clear cups, kitchen roll, red, yellow and blue food colouring, water
- Stand six cups in a circle.
- Half fill every other cup with water and add a different colour to each.
- Fold strips of kitchen roll and bridge each full cup to its empty neighbour.
- Check back every 15 minutes.
- Spot the new colours appearing in the empty cups.
Float or Sink Egg
Make an egg float halfway up a glass using nothing but salt.
You'll need: raw egg, tall glass, warm water, salt, tablespoon
- Gently lower an egg into a glass of plain water and watch it sink.
- Lift it out with a spoon.
- Stir in tablespoons of salt one at a time until it dissolves.
- Lower the egg back in and see if it floats.
- Wash hands after touching the raw egg.
🧑 The grown-up bit
Heating lemon ink is a grown-up job: use an iron with no steam, never a candle, hob or toaster, and keep children back from the hot plate. Vinegar and salt water sting eyes, so keep hands away from faces and rinse with cool water if a splash happens. Check for food allergies before anything with milk or eggs, and make sure nobody eats or drinks the experiments. Wash hands after handling raw eggs.
Questions parents ask
Can my child taste the experiments?
It is best to treat everything in the lab as not for eating, even if it started as food. It keeps the habit simple, and some mixtures contain washing-up liquid or lots of salt.
My bicarb volcano barely fizzed. What went wrong?
Usually the bicarbonate of soda is old or there was not enough vinegar. Use fresh bicarb, add a good splash of vinegar at once, and a squirt of washing-up liquid to trap the gas in foam.
Can I use a hairdryer for the invisible ink instead of an iron?
You can try, but most hairdryers do not get hot enough to brown the lemon juice. A grown-up using an iron on a medium setting with no steam is the most reliable method.