Fun kitchen science experiments
From a table top volcano to a liquid that rolls into a ball, you can find everything you need in your kitchen cupboards. Learning has never been so messy – or so much fun!
A liquid that rolls into a ball?
Children love to get messy and mixing cornflour with water is great fun. What you do with the gloopy mixture is where the science experiment starts.
You will need: Cornflour, water, a container, plus a dustsheet or newspaper for the mess.
Directions: Pour water into a large container of cornflour - about one part water to one-and-a-half-parts flour, or you might need a bit more flour. Mix slowly until the consistency resembles thick custard. It pours like an ordinary liquid but apply pressure and it becomes solid. Take a piece and roll it into a ball! But it doesn’t stay solid, it melts and drips away. Running your fingers through this mix is a fascinating experience. What happens if you hit it?
Now for the science bit: Cornflour mixed with water creates a non-Newtonian fluid. Normal Newtonian liquids (like water) flow in a predictable way and have a constant viscosity, which means they only change how they behave if you boil or freeze them. Non-Newtonian fluids behave differently when a force is applied. Some become thicker if you shake or stir them, some become runnier - some react to the amount of force, others to the length of time the force is applied.
Which came first, the chicken or the egg? We don’t have the answer – but we know what an egg looks like naked! This experiment requires a little patience but is worth the wait.
You will need: A glass or jar, an egg in its shell, clear vinegar.
Directions: Take a glass or jar and place the egg inside. Cover with clear vinegar and wait 24 hours. The next day, pour the vinegar away and cover with fresh vinegar. Leave for seven days – then carefully rinse the egg with water.
Now for the science bit: The acetic acid of the vinegar reacts with the calcium carbonate of the shell – breaking it down into calcium and carbonate. The calcium is contained in the solution while the carbonate reacts to form carbon dioxide, which you will see as bubbles. Once the outside shell of the egg is gone, it will be ‘naked’ and appear translucent. Try shining a light through the egg or gently bounce it. The egg will eventually harden again once it reacts with the carbon dioxide in the air.
Table top volcano
Another acid alkali reaction – this one is perfect for kids who don’t like to wait. The results are immediate and, as you might have guessed, explosive!
You will need: Baking soda, vinegar, a bowl, a tray and protective newspaper or sheets. Food colouring, a plastic bottle and papier-mâché volcano (make with newspaper, flour, water), optional.
Directions: Mix baking soda with vinegar in a bowl and watch it fizz. But why stop there? Add food colouring to the baking soda to make pretty coloured fizz - or mix the two substances in a bottle and watch it bubble over and out of the top. Arty types can make a papier-mâché volcano (remember that Tracey Island you made years ago?). Once you’ve finished your masterpiece, place a plastic bottle underneath the mountain. Add baking soda, warm water and red food colouring to the bottle. When you’re ready, pour in some vinegar and watch the lava flow.
Now for the science bit: When baking soda (sodium bicarbonate) is mixed with vinegar (acetic acid) it causes a chemical reaction which creates carbon dioxide gas – and it’s this that produces the bubbling lava flow.
Groovy tie-dye milk
Who says tie-dye is just for clothes? Milk, food colouring and detergent are all you need to create some groovy patterns, while teaching your little ones about science.
You will need: A shallow dish, full-fat milk, washing-up liquid, food colouring, plus dustsheet and old clothes to protect against stains.
Directions: Cover the bottom of the dish with full-fat milk and add a few drops of different food colouring. Pour a drop of washing up liquid into the middle of the dish. You don’t need to stir it - the detergent will make the food colouring swirl around, creating amazing patterns as if by magic.
Now for the science bit: The detergent reacts with the milk, weakening the chemical bonds that hold the proteins and fats in solution - the same process that allows washing-up liquid to remove grease from dirty pans. As the soap molecules race to join the fat globules in the milk, the food colouring molecules are forced around, providing a good way to see the otherwise invisible activity. Once the detergent has become evenly mixed with the milk, equilibrium is reached and the movement slows down and finally stops.