Comments on: What combinations of clear, non-toxic chemicals create a colourful result?

Question: What combinations of clear, non-toxic chemicals create a colourful result?

greatgefilte — Fri, 03 Jul 2009 16:17:56 -0800

What combinations of colourless non-toxic substances result in something that's coloured, or at least opaque?

Aside from enzymes and substrates, are there any safe organic and/or inorganic clear substances that are known to change colour in the right combination? I vaguely remember doing things like this with a childhood chemistry set, but can't remember the specifics.

By: carmicha

carmicha — Fri, 03 Jul 2009 16:36:09 -0800

Ouzo and water mixed together become milky white: it's the ouzo effect.

By: rokusan

rokusan — Fri, 03 Jul 2009 16:45:37 -0800

Safe is relative, but sodium carbonate + phenolphthalein (in clear alcohol) turns reddish pink. Thymolphthalein (also in alcohol) + sodium hydroxide comes out garishly blue.

Sodium hydroxide is pretty caustic. The rest isn't too nasty.

By: Captain_Science

Captain_Science — Fri, 03 Jul 2009 16:48:04 -0800

Phenolphthalein is colorless in acidic solutions and is a light pinkish in basic solutions. I don't know what you mean by safe...just that you wouldn't want to ingest phenolphthalein given its historical use as a laxative.

By: pseudostrabismus

pseudostrabismus — Fri, 03 Jul 2009 20:22:51 -0800

Tonic water will fluoresce under a blacklight.