Posting Comment for "Cabbage Indicator"

*Author Name
Email Address
Website URL

About Posting a Comment

Comments are moderated before they will appear on the website, this is a manual process and may take some time. Please be patient.

Author Name is a required field.

Email Address is optional, but without one I won't be able to contact you back. It is never shown or linked on the website. You can always just email me if you'd rather not post a public comment. I generally reply in-line with a comment rather than email you back, unless I want to discuss something in private or off topic. Please check back to see when I reply.

Website URL is optional, if supplied the Author Name will be hyperlinked to this URL.

You may use wikitext in the body, preview may be handy here. Don't worry if you can't figure them out, just give me a hint what you want linked to what and I'll do it during moderation. Wikitext is not BBcode!

Spammers: Please don't bother wasting your time scripting up posts to this form. Everything is moderated, your post will never be seen on the web even transiently, there is no way to even view it by its internal ID, it will never be indexed. I will simply delete your post in the moderation interface. If I'm your target audience you're really on the wrong track; I'll never click on a URL in your garbage. The post content is not emailed to me (and I don't use a Win32 mail client anyway), I view the posts in plain text in the moderation interface so no clever tricks of any kind will make anything you type be interpreted by anything other than me, a human. Just give up and go elsewhere please!

6th December 2009 17:13

Alan Yates wrote...

Tony,

Yes I recall doing the beetroot experiment when I was a child.

I read about using Turmeric as an indicator for Boron. I tried making up some paper with it... I got no visible reddish colouration on drying after exposure to boric acid or borax. Got a speckle of light blue coloured bits after re-moistening with NaOH solution, but it was still mostly yellow.

Maybe I prepared the paper improperly? I used warm methanol to extract the turmeric, filtered and applied to bleached coffee filter paper, then air dried. Maybe that extracts other yellowish compounds that do not react with Boron? Hopefully it wasn't the paper!

Regards,

Alan

4th December 2009 08:07

Tony Webb wrote...

You can also use beetroot pigment, which has quite an interesting heterocyclic structure (to an Organic Chemist). It fades with alkali, goes red again with acid. Turmeric (curry powder) also has indicator action.