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Custard Gone Crazy

Well, CAN you walk on custard?

You will need:

• Custard powder (or cornflour – but not instant custard powder)
• Water
• Eggcup
• Bowl
• Spoon
• Food colouring (optional)

What to do:

1. Put 8 eggcups of custard powder or cornflour into a bowl.
2. Slowly add 3 eggcups of water, gently stirring the mixture as you add the water to make sure you don't get any lumps. (Still too dry? Add a little bit more water.)
3. The result is a strange yellow substance that can act like a solid (if you punch it quickly or roll it into a ball) and also acts like liquid (if you touch it gently). Weird.
4. If you increase the amounts of custard powder and water, you could in theory fill a paddling pool with the mixture, and run across the top without falling in. (If you do this you can jump up and down, but when you stop jumping you sink into the mixture. To remove your feet pull gently or you may be stuck there for good!)

What’s going on?

When you move the custard mix around slowly the custard powder particles can move around in the water quite freely, and so it acts as a liquid. When you move the mix faster or hold it in your hand tightly, the solid particles rub against each other causing friction. This makes them stick together and act like a solid.A solid-liquid mixture that behaves in this way is called dilatant.Another dilatant mixture is quicksand – a mixture of sand and water. If you are ever stuck in a patch of quicksand, don’t start to thrash about wildly! The sand particles stick together and it will be harder to get out. But if you move very slowly, the quicksand behaves like a liquid and you can get out, or just lie back and float on it if you prefer.So can you walk on custard?  Yes if the mix is right and you walk quickly, but don’t hang about else you’ll mess up your Nikes good and proper! Try explaining that to your parents.

This experiment came from Planet Science’s Little Book of Experiments.

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Remember Issue 68 when we were giving away three Okido magazines? Well the lucky winners are Andrew Stevenson (7) of Manchester, Matty Nicholson (4) of Glasgow and Ewan Harold (7) of Aberdeen.  Congratulations! So remember – keep entering ‘cos next time it could be you!

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What do you call a snowman with a suntan?
A puddle.

Two children were talking in the playground.  The first child says: “My mum is from Ireland and my dad is from America.  That makes me an Irish-American.”  The second child says: “Well, my mum is from Iceland and my dad is from Cuba. So I guess that makes me an Icecube.”

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