Thursday, 25 February 2010

Dancing raisins

I have Tall Small with me today - she had a tummy bug which is all better now but our school sensibly has a 24 hour quarantine policy after little ones stop throwing up, so she is feeling fine but stuck with me.

What to do? We've done multiplication squares and fed the birds, and then she asked to 'do some science'. Well, am I likely to say no?

So, here's a old but good recipe to entertain a small not-very-ill person:

Take one glass and fill with something clear and fizzy - we used tonic water but lemonade or soda water would be fine too.


Add a raisin.


Watch as bubbles of carbon dioxide form on it and carry it up to the surface. The bubbles will burst and the raisin will fall, and then rise again, and fall again over and over till the liquid goes flat.


And if one raisin is fun, why not try a handful?


Just don't try to drink it afterwards ...

Edited to expand the science bit:

Fizzy drinks fizz because the CO2 in them only stays in solution whilke the drink is under pressure in the bottle or can; when you open the can the CO2 comes out of solution and escapes as bubbles of gas. The raisin - or indeed anything else - forms a nucleation point for the bubbles to get caught on. Once enough bubbles are formed on the raisin, it becomes buoyant and floats up to the surface. When the bubbles reach the surface of the drink the CO2 can escape into the air and the forces holding the raisin up are overcome by gravity so it sinks again. Hope that's a bit clearer!

24 comments:

  1. How fun! Maybe your little scientist would like flat raisin water? And I love your cute little heart glass too!

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  2. Ah but I also need all the whys! Maxi would drive me inside with why, why, why!

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  3. glad the small is feeling better - our school has a 48 hour policy.....

    love the raisin dance xox

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  4. Mine are sufficiently old enough now that while they would enjoy all the cleverness of raising raisins they would also be daring each other to drink said flat raisin water!

    Glad Tall Small is feeling better.

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  5. It drives me mad when people bring their kids to school and cheerfully tell the teacher 'X was sick in the night, but seems fine now'. Little germy time bombs.

    Anyway, an unexpected not-too-sick day is always a bonus (especially one with bionic raisins).

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  6. What fun! Glad she's feeling better and hope no one else succumbs.

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  7. Sorry to hear you've had a poorly small but very glad to hear that she is better! Love the dancing raisins - I'm going to show the little Lockets that one later! Lucy xxx

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  8. What fun you both must have had!

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  9. glad she's on the mend - i love that raisin experiment - just brilliant!

    xx

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  10. I wish I was off sick with you!

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  11. You know I love it when you do science experiments! Yippee! Yahoo! Thank you! Off to purchase some fizzy water...

    (Hope no one else succumbs to the barfies.)

    P.S. My word verif is "makeriti," which seems to suit your very clever crafty self. Although I suppose you would be a makerita...

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  12. Neat. If you can't drink the liquid afterwards, can you eat at least the raisins?

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  13. Very impressed Tall Small asked for a science lesson on her day off! K x

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  14. How fab, will have to try that, my son loves anything sciency (and I do too :-)). I will be popping on of his science experiments on my blog soon which is done with household stuff.

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  15. lol, just showed my son this and he wants to know 'is that why you burp after fizzy drinks?'. Well I suppose the answer is yes :-)

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  16. I love your science-y posts - this one I'll jot down for a rainy day with Amy. Glad that Small is over the bug and that you had fun with her all to yourself.

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  17. I remember my little ones doing this at preschool...we have spring break next week and they're on a mission to make their own bath bombs. Now I need to get my hands on powdered citric acid... Glad Tall Small is better x

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  18. My small people like this too but we add a drop or two of food colouring and prop a torch up behind the glass; make your own lava lamp! x

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  19. I'm going to try and impress my children with this tomorrow!
    Hope nobody else gets the bug.

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  20. The things you get up to...! Hope Tall Small is now as right as rain. This made me smile, and I might just succumb to having a little science experiment myself.

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  21. While that is amazing and really interesting the thought of raisins floating in your drink is disgusting!

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  22. That's fantastic! I wish you'd been my science teacher when I was at school - you make it so interesting! Hope your little one is all better now. :) x

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  23. Who knew raisins could be that much fun? ;o) Do hope your Tall Small is feeling better... Happy Weekend to you all ((HUGS))

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