While researching last week's Science Sunday experiment, I came across a couple of experiments, dealing with carbonic acid, that I thought would be fun to try out with the kids, today.
Carbonic Acid (H2CO3) is a combination of water (H2O), and carbon dioxide (CO2). It is also what causes that slightly uncomfortable, tingling sensation on your tongue when you sip your soda pop. We experienced this for ourselves, with an experiment from Education World.
I gave each of the children a small cup of pop (they are always interested in soda pop science, because we don't normally give them pop to drink), and then timed them to see how long they could hold their tongues in the liquid. It proved to be a very difficult challenge!
We used pH paper to test the acidity of Coke Zero. Not surprisingly it showed high acidity. What was surprising though, was our flat soda, one of Daddy's old ones we pulled out of the fridge :), was also quite acidic, though the flat soda didn't hurt the tongue. After checking the ingredients on the side of the can, we decided this was due to the presence of the phosphoric acid (also what makes Coke a good rust remover!).
Keeping our findings above in mind, we moved on to another experiment we found on the website of Wind Cave National Park. This time, we tried to make water acidic by adding carbon dioxide to it. Where did we get the carbon dioxide?
If there's one thing we learned from watching Apollo 13, last night, it's that people breath out carbon dioxide!
Following the instructions of the experiment, we tried blowing through a straw, into a glass of water for one minute, and then testing the acidity of the water with pH paper. We tried it with cold water, and warm water. We tried it with a full glass, and with an almost empty glass. And we tried it with one person blowing into the glass, and with two people blowing into the glass. But, we couldn't seem to make carbonic acid. Our pH papers looked just the same before, during, and after we blew into the water.
This was disappointing, but it did give us a chance to discuss the fact, that there are a number of variables, that can effect the outcome of an experiment. Were our straws too big? Were we blowing too vigorously? Did the water need to be warmer? We used filtered water, instead of distilled water, would that make a difference? Hmm...we have a lot to think about.
In the meantime, you can find a number of other fun, and hopefully successful, science experiments, and projects for children, at this week's Science Sunday link up, hosted by Adventures in Mommydom.
It's great to be a homeschooler.