The best laid plans......

Lydia over at Little Blue School gave me a great idea for a science experiment. She suggested we look at how anthrocyanins, the purple pigment in plants, can work as an acid/base indicator.

i was psyched. I worked out how to teach the children a little bit about plant pigments and a little bit about acids and bases.

The little lesson on plant pigments went well. They were fascinated by the color changes this fall so this made a lot of sense to them. However, I started boiling the purple pansies before I started teaching them about acids and bases. Bad, bad mistake. Boiling flowers take precedence over exchanges of hydrogen ions.

I gave that up as a bad idea and moved onto the experiment. It all started well, I put out 6 little cups of purple liquid full of anthrocyanins and another 6 little cups, 2 with acids, 1 with a base and 3 neutral. They started with baking soda. Going well so far, then the neutrals. Scream of delight when they saw how the vinegar turned the purple water pink.

Then mom came up with the bad idea. "Why not see if the indicator changes color if you turn it basic again by adding baking soda". Mmm, know what happens when you add a large amount of baking soda to something that already has a large amount of vinegar in it? That's correct, we have a wonderful bubbling mess.

That was the end of this experiment. All they wanted to do was alternate adding baking soda and vinegar to all the cups to see who violently they could make them overflow. Thank goodness I contained the experiment on a tray.

Here you have B&S preparing the pansies.



Watched pots never boil



Aah, nearly ready



Pansy juice all lined up with acids and bases. Thank goodness for that tray. It saved me a whole lot of cleaning.



IT WORKS!!!! The anthrocyanins change color it the presence of an acid.