The best kitchen science experiments
Creating tornadoes, setting off volcanoes, growing edible crystals: these pulse-quickening experiments require only require the most basic of ingredients
1. Create your own tornado
A simple but impressive experiment to get you and your children started. All you need is an empty 2-litre drinks bottle (a glass one is best but a plastic one will do), a little olive oil and some water. Fill the bottle very nearly to the top with water. Pour in a tablespoon of olive oil. Cover the top of the bottle with one hand and tip it upside down (you may want to do this outside or over a sink). Rotate the bottle in a clockwise direction (if using a plastic bottle, try not to squeeze a dent in it). Here comes the tricky bit: whilst continuing to swirl the water around, lower your hand from the opening of the bottle. The oil, being less dense than the water, is sent whizzing out from the vortex you've created – your own miniature tornado in a bottle.
2. Grow edible crystals
As this experiment takes place over several days it's a good one for a summer holiday, and since it involves making something sweet to eat it's likely to go down very well with your kids. In a saucepan, mix three cups of sugar with one cup of water and bring briefly to the boil, stirring continually. Allow to cool a little in the fridge, adding food colouring and/or flavouring to taste. Pour the sugar solution carefully into a clean glass jar. Wrap some string around the middle of a pencil so that, when you place the pencil over the jar, the string hangs down into it until it nearly reaches the bottom. Over the next three to five days beautiful sugar crystals will magically form around the string. If crystals grow on the surface of the solution, you can scoop them up and eat them too. It's all good.
3. Start your own plastics factory
Up until now, polymer chemistry has been largely the preserve of serious-looking scientists in lab suits who, it turns out, have been cleverly hiding the fact that it's actually a lot of fun. To make some of your own squidgy plastic, simmer a pint of milk in a pan (but don't let it boil). Add 20ml of white vinegar and stir until some yellowy rubbery globules begin to form as the solution clears. Remove from the heat. When cool, sieve the globules and (slipping on some rubber gloves) wash them in water. To make bigger lumps, press the globules firmly together and play with them in your hands until they join up. Your children can now set about crafting the plastic into the form of model cars or prancing ponies!
4. Set off a volcano
Possibly the most rewarding thing you and your kids will ever do in the kitchen. Grab a large bowl and get some small hands to mix together 850g of plain flour, 320g of salt (don't worry – nobody will be eating it), 480ml of water and 4 tablespoons of cooking oil until smooth but not sloppy (you can vary the amount of water to obtain the right consistency). Place an empty half-litre drinks bottle in a large oven dish and mould your mixture around it to form the volcano's cone. Unscrew the cap and pour in warm water almost to the top. Add a splash of red food colouring, six drops of washing-up liquid and two tablespoons of bicarbonate of soda. Have someone ready with a video camera and gently start to pour vinegar into the bottle. Your family's volcano will erupt with a satisfyingly realistic flow of bright red carbon dioxide foam 'lava'.
5. Fashion a soap sculpture
Microwave ovens aren't just for heating up boring old food. Try popping a kitchen towel in one with a bar of soap on top. Nuke it with all those lovely microwaves and your kids will watch amazed as the bar grows up to six times its original size. Turn off once the soap has stopped expanding (depending on the power of your oven, this will take around two minutes) and allow to cool. You'll be left with an amazing abstract sculpture! If you want to impress your kids with your mastery of chemistry, you can tell them that they've just witnessed a demonstration of Charles' Law ('the volume of a gas increases with its temperature'). Oh, and should you all tire of looking at your work of art, you can just use it as soap.