Saturday, March 3, 2012

Homeschool Chemistry: Acid Plus Base

As the first two demonstrations in the girls' fabulous chemistry set, acid plus base experiments are so easy, so fun, and so wildly rewarding that still, my girls do these two demonstrations over and over again, each time absorbing more information about the science behind the reaction and learning more about the tenets of chemistry.

Of course, we've long used up the chemistry set's supplies of baking soda and citric acid--fortunately, since we often bake and preserve, we've got both of those materials in our kitchen stores, and I tend to buy vinegar six gallons at a time when it's on sale, since it's about all I use for cleaning. Nevertheless, whether or not you own a chemistry set, I still highly recommend a good stock of nice glass test tubes and cheap plastic eyedroppers; the eyedroppers allow children to have more control over the amount of water or vinegar that they add to their mixtures, and the test tubes are really ideal for observing the chemical reaction.

Experiment #1: Small Scoop of Baking Soda, Eyedropper of Vinegar

It's nice to keep the amounts very small so that the chemical reaction between the sodium bicarbonate and the ascetic acid is easy to observe. Notice the bubbling, notice the fizzing, notice the foam!

Experiment #2: Small Scoop of Baking Soda, Small Scoop of Citric Acid, Eyedropper of Water

I think that this version is even more fun, because the two powders, one an acid and one a base, nevertheless do not react--

--until you add water as a catalyst!

  • Look up the chemical formula for each ingredient, then explore the elements that make up the formulas.
  • Write an illustrated tutorial for each experiment.
  • Use the chemical formulas and the scientific notation of the chemical reaction as copywork or memory work. 
  • Compare other liquids to water when conducting Experiment #2. Does rubbing alcohol affect the reaction? Does orange juice?
  • Play with the reaction as a sensory experience, as long as you don't have any cuts on your hands. Neither vinegar nor citric acid are strong enough to hurt healthy skin, so get out a big baking pan (or go outside--I wish!) and make big piles of baking soda, on which you drop vinegar rain.
  • Add powdered tempera to either the baking soda or vinegar to make fizzy paint.
  • Make and erupt the traditional baking soda and vinegar volcano.
  • When the kiddos were finally finished with their play (nearly an hour later!), they asked me what they could do with all their test tubes and mason jars of vinegar. I suggested that they use it to scrub the kitchen floor--and they did! 
It WAS a productive morning!


Teresa Robeson said...

You did science expts with the kids AND convinced them to clean the floor?! I am so not worthy to be on the same planet as you.

julie said...

We also had take-out three nights in a row, did I mention that?

Teresa Robeson said...

Well, you can't win 'em all. (I get the feeling that some people would say "take out?! Extra win!" but I'm not one of those people.)

Anonymous said...

Wow! they cleaned the floor too! lol ~> Love it ;)

Keri- A mom who is enjoying the homeschool elementary
stage, of her homeschool journey!

julie said...

That's why I knew it would be the perfect confession for you.

Tina said...

I will have to keep an eye out for some inexpensive test tubes. We did the red cabbage juice experiment a while back, but because we were using mason jars, we went through our "juice" very quickly.

We have vinegar and baking soda, might have to see if we have citric acid, or what we can use in its place.