The same recipe our presenters use in 1,800+ UK schools — now yours, for your kitchen table or your back garden. Plus a DIY giant-bubble wand made from coat hangers, three smaller bubble experiments for younger siblings, and the science behind all of it. Reception–Year 6.
This is the actual mixture our Spark2 presenters use in the school workshop. Costs less than a fiver — most kitchens already have everything except maybe the cornflour.
Bubble mixture is slippery — wipe up any spills straight away. Outside is best. Children should remove loose-fitting clothing before stepping inside the bubble.
Around £3 from any DIY shop. Two wooden dowels, some kitchen string, a metal washer. Children can build it themselves with help — that's half the fun.
Pro tip: the absolute biggest bubbles come on cool, damp evenings with no wind. If it's a bright sunny day, try doing it after dinner instead — the cooler air slows evaporation and the bubble lasts much longer.
If your child asks, here's the answer in language a 7-year-old can follow — and a 12-year-old can dig deeper into.
Soap molecules have a water-loving end and a water-hating end. They line up between layers of water like little soldiers, holding the film together. Without soap, water just falls — there's nothing to hold the film up.
Cornflour and baking powder thicken the water just enough that it doesn't drain out of the bubble film too fast. That's the actual magic — without them, your bubble pops the moment it leaves the wand.
Those rainbow swirls? That's thin-film interference — the same physics behind oil-on-water rainbows and the iridescent shimmer of a magpie's feathers. Different layer thicknesses reflect different colours of light.
They pop when the water inside the film evaporates faster than gravity can drain it. Heat, sun, dry air = pop quickly. Cool, damp evening = the bubble lives for ages. Test it yourself.
If the giant bubble is too much for an indoor day, or you've got a 4-year-old who wants to join in, here are three smaller experiments. All cost almost nothing.
Cut the bottom off a plastic bottle, stretch an old sock over the cut end, secure with an elastic band. Dip in soapy water. Blow gently into the open neck. A long "snake" of foam pours out the sock end.
Add 1 tbsp glycerin to your bubble mix — it's the secret. Now bubbles are strong enough to bounce: blow one in the air, catch it gently on a wool scarf or fluffy mitten and pass it between hands. Or use a straw to blow a dome on a tray, then blow more bubbles inside the first one.
Add a few drops of food colouring to the bubble mix. Blow bubbles onto paper using a straw. When they pop, they leave a coloured ring print. Layer different colours for proper artwork.
The giant bubble is one experiment. We're building a free at-home pack for every Spark2 workshop — from first aid to engineering to mental wellbeing. Get the next one as soon as it's ready.
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