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Author Topic: Clear liquid + clear liquid = Blue Liquid HELP!!!  (Read 9492 times)

Offline shiftdelete

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I need some help with an experiment / visual illustration.

I would like to have 2 glasses of "water" (or clear liquid).

Then take a small eyedropper containing some type of indicator.

Put a few drops into each glass.

Glass 1 glass will stay clear, while Glass 2 will need to turn BLUE. (will also be happy with RED, but blue is my first choice).

This needs to be done as safely as possible (I will be on stage, no safety goggles). And as efficient as possible.

Any help would be GREATLY appreciated.

Thanks in advance,

Shiftdelete [^]


 

Offline Bored chemist

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Clear liquid + clear liquid = Blue Liquid HELP!!!
« Reply #1 on: 26/03/2009 21:26:21 »
OK Don't drink any of the liquids but...

A solution of sodium carbonate (washing soda) in the glass would turn phenolphthalein pink.
At slightly greater risk, a dilute (about 0.5% will do, you might want to try less) solution of sodium hydroxide (AKA caustic soda)would turn thymolphthalein blue.
The two phthaleins are soluble in alcohol so you could add a few drops of a solution in vodka to the glasses of liquid.
Phenolphthalein is available on ebay because it's used for testing biodiesel.

Another aproach would be to add a few drops of ink to two glasses, one with water in and the other containing bleach- but that doesn't give me an excuse to write really long words like phenolphthalein and thymolphthalein.
Any of those liquids is nasty enough that, if you manage to splash it in your eye, it's time to stop the show, wash it out under the cold tap and maybe go to ER/ Casualty to get them to check for damage.
And remember don't drink any of the liquids.
 

paul.fr

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Clear liquid + clear liquid = Blue Liquid HELP!!!
« Reply #2 on: 26/03/2009 23:26:10 »
Quote
Another aproach would be to add a few drops of ink to two glasses, one with water in and the other containing bleach- but that doesn't give me an excuse to write really long words like phenolphthalein and thymolphthalein.


BC, do you mean food colouring in one glass and bleach in the other?
You put a few drops of food colouring in one glass (colouring not visable to audience) and a small amount of bleach in the other. When you pour water in the glass with the colouring in it the water changes to that colour. You then pour the contents of that glass in to the other glass (that only contains the bleach), the bleach then "bleaches" the colour out and you have clear water left.

This should work with mixing colours as well, by adding glasses and mixing then before finally pouring in to the bleach glass. glass 1 has blue food dye, glass 2 has red, when poured from one to the other they produce...purple! before being bleached out...
 

Offline shiftdelete

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Clear liquid + clear liquid = Blue Liquid HELP!!!
« Reply #3 on: 27/03/2009 04:58:54 »
Thanks for the replies. First- I need both glasses to be full of clear liquid from the start, so the food color / bleach method will not work for me.

Seems like phenolphthalein is what I will try as it seems much easier to obtain. Is washing soda the same as baking soda? And will that still appear to be a clear liquid once the baking soda is added?

I'll check to see if the blue stuff is available anywhere also.

If you have any other suggestions, please feel free.

Thanks,

Shiftdelete


 

The Naked Scientists Forum

Clear liquid + clear liquid = Blue Liquid HELP!!!
« Reply #3 on: 27/03/2009 04:58:54 »

 

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