The set-up was to boil a few leaves of red cabbage in some water, then add the bluish water to vinegar in a 2L bottle. Next, he was to put some baking soda into a 6-9" balloon. He was supposed to attach the balloon to the top of the bottle without letting any of the baking soda fall into it just yet. So while I boiled the cabbage for him, TBear went in search of a balloon.
Unfortunately all we had were those tiny water balloons. Then TBear hit on the brilliant idea of a rubber glove from the barn. I wasn't sure it was a brilliant idea yet : ), but it was an experiment, and the glove was about the right size, so why not.
Pouring the bluish cabbage water into the vinegar
Getting that glove with the baking soda in it rubber banded to the top of the bottle was interesting. Here he is adding the baking soda from the glove into the blue vinegar
Whoa! The glove worked! Apparently there was enough carbon dioxide produced to inflate the glove. (The baking soda combined with the vinegar produced carbon dioxide, sodium acetate and water.)
And the more you shook the bottle to mix up the baking soda, the bigger the glove got.
Fortunately I took pictures because he was also supposed to notice the change in the color of the vinegar water from blue to pink and back to blue again as a second chemical reaction was taking place. TBear commented on it, but then had to think about it when the question was asked. : ) The second reaction happened as the vinegar was used up. Something from the red cabbage (anthocyanin) interacted with the vinegar to turn the water pink. As the vinegar was used up in the baking soda reaction, the water returned to its blue color.
I love fun science! I also love the creativity of TBear. I never would have thought of the glove; I'd have just put the experiment off until after I'd found a balloon.
The expression on this face is too funny. It looks as if he's saying "Watch Out ! It's gonna blowwwwww !!" HA !
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