Kitchen science experiments with cupboard ingredients

A small plastic bottle is hidden inside a mountain of scrunched newspaper and card, painted brown or grey. Baking soda, washing-up liquid and red food colouring go in, then vinegar, and foamy lava whooshes out. The foam is carbon dioxide gas, made when an acid meets a base. Stand it on a tray and keep vinegar away from eyes.

Drop four or five raisins into a tall glass of freshly opened fizzy lemonade or soda water and they rise, sink and rise again. Bubbles cling to the wrinkly surface and lift each raisin, then pop at the top. It takes 15 minutes and suits ages 4 to 9. This one is for watching, not drinking.

Children write a secret message on plain white paper with a cotton bud dipped in lemon juice, then leave it to dry until it vanishes. Gentle warmth brings the writing back in brown, because lemon juice browns faster than the paper. An adult must do the warming, with a radiator or warm lamp the safest choice.

Two cups of cornflour and about one cup of water make a mixture that feels solid when punched fast and drips like a liquid from a slow handful. For ages 3 to 6, it is a hands-on first look at how materials can behave in surprising ways. Wet cornflour makes floors slippery, so wipe up spills straight away.

A deep tray of plain flour dusted with cocoa powder stands in for the surface of the Moon. Dropping a marble, a bouncy ball and a small stone from different heights leaves craters to measure with a ruler, showing how the size and drop height of a space rock change the crater. Lay newspaper down first, as flour flies out.

Milk or single cream, sugar and vanilla are sealed in a small freezer bag, then tucked inside a larger bag of ice and salt. After 5 to 10 minutes of shaking it freezes. Salt makes ice melt at a colder temperature, which pulls heat from the cream. Hold the bag in a tea towel, as it gets extremely cold.

Icing sugar, food-grade citric acid and bicarbonate of soda are stirred together in a completely dry bowl. Nothing fizzes until a dab meets a wet tongue, where the acid and the soda react and pop. The whole thing takes 15 minutes. Use clean bowls and hands, and go easy, as too much citric acid can sting.

Lemon juice, sugar and cold water are stirred together in a tall glass. A small pinch of bicarbonate of soda then makes it fizz and foam, because the soda reacts with the lemon's acid, so children aged 5 to 10 carbonate their own drink. An adult cuts the lemon. Use food-grade bicarbonate and only a pinch, or it tastes soapy.

Tuck a dried broad bean or runner bean between damp kitchen roll and the side of a clear jar, then stand it on a light windowsill. Over about a week the roots grow down and a green shoot grows up, all in plain view. Add a little water if the paper dries out. Dried beans are for growing, not eating.

Left in a glass of white vinegar for two days, a raw egg loses its shell. Tiny bubbles form as the acid dissolves it, leaving a squishy egg inside its bendy membrane. The egg also swells as water moves in, which is osmosis. Handle it gently over a tray, as it is still raw inside and can burst.

Chopped red cabbage soaked in hot water gives a deep purple juice that works as a natural indicator. Shared between clear cups, it turns pink with lemon juice or vinegar and blue or green with bicarbonate of soda. For ages 6 to 12, with an adult pouring the hot water and the juice cooled before use.

Salt or sugar is stirred into very hot water in a jam jar until no more will dissolve, which means the water is saturated. A string weighted with a paperclip hangs in the jar, and crystals slowly grow along it as the water evaporates. Best for ages 8 to 12, with an adult handling the hot water.