Tuesday, August 28, 2018

Simple Science: Acids and Bases

It has been way too long since I did any posts with science experiments!  Here's one we did recently to introduce the concept of acids and bases (we did not get into PH or the chemical reactions that occur with them).  

From conversations we've had when he's been sick or when pregnancy gave me heartburn, Xander already knew that certain foods like citrus fruits are acidic.  We explained that bases are the opposite of acids and neutral means something is neither acidic nor basic.

To prep, I cut up a head of purple cabbage and then boiled it about 6-7 cups of water for 15 minutes and strained it.  I was supposed to use distilled water, but accidentally used filtered instead and it still worked.  Now I have a jug of distilled sitting around.  Oops.

Then I had Xander line up a bunch of glasses and we added a different liquid to each one.  I had Xander make a list of the different liquids, so he could make predictions and record observations.  We used pickle juice, lime juice, milk, hot sauce, water with baking soda, white grape juice, sparkling water and regular water (for the control).

Then I had Xander try each one and write down observations about how it tasted. 
I only let him dab his finger in the hot sauce instead of trying to drink it. 
Then I had him add 1/4 cup of the cabbage juice to each cup and we recorded what happened.  We were looking for color change.  Then I had him use the color changes to try to determine which was the strongest acid and which was the strongest base.  (It will turn bright pink for acids and teal for bases).

It ended up being a fun way to spend an afternoon.  Xander concluded that acids usually taste sour.

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