Australia's Science Forum

Hello labbie land
have a question for you all..........
i have not been able to find my list of flowers to use for the indicator prac; the one where you boil up red cabbage as a universal indicator and then use other flowers to use as indicators with more limited ranges. I once had a list of good flowers to use and their ranges - does any one have a list like this ?? If not can you give me an idea of what you use please.


At the end i will compose a list and send it out to those in need or post it here (please dont request it now as i will lose the list and upset people - dont want to do that )

I'm not sure of the flowers, but I have used beetroot, spinach, red and brown onion skins, fennel and wattle along with red cabbage for dyeing calico. We change the colour by adding mordants (alum, copper sulfate, cream of tartar, vinegar, bicarb soda, salt, ammonia) These would produce pH changes, so the vegies could be used as indicators as well.
Ellice.

Red Hibiscus in diluted Metho (Pink) in acid sln (orange) in alkali sln (blue- green)
red Rose "" (Pink) '' (Pink) (Olive green)
red canna " (red) " (orange) "" (dark green)
red dahlia " (red) (orange-red) "" (amber)
mauve impatiens " (mauve) " (pink) " (green)
purple aster " (purple) " (pink) '"" (green)
white rose " (colourless) " (colourless) """ (amber)
raw beetroot " (red) " (red) " (yellow)
Can be ground up with a little sand and metho to obtain a solution - we just grind up using a little water!! Works just the same with the acids and alkalis
I believe cochineal can also be used as an indicator - although I must admit I haven't!

Judy.

We have also tried purple flowers - jacaranda, violet etc with a fair amount of success. Interestingly we found that Paterson's Curse did not work as an indicator. We have also used Rose Hip & Red Hibiscus tea bags with a reasonable range. That is also a good prac for Primary grads, as there is no chopping/grinding involved. Just make a cup of tea, then use it to test things with.