Kitchen chemistry experiment

I keep a plastic container full of frozen blueberries in the freezer. When it's empty and I rinse it out, I always noticed that the residue in it went from reddish to blueish as I added more water. Eventually, I realized it's because the juice is an "indicator", that is, something that changes colour depending on the acidity of the water.

So I googled it. Blueberry juice changes colour going from neutral to acidic, and as I dilute it with more water, it becomes less acidic.

Beet juice is an even better indicator solution. So I wanted to experiment with changing the beet juice from acidic to basic and back.

There are many food substances that are acidic, but bases tend to taste bitter so they aren't exactly food substances. But then I realized, I had some clear drain unclogger. The active ingredient in that is sodium hydroxide, a very strong base. In fact, sodium hydroxide is probably the only ingredient. So using drain unclogger, I could cycle the beet juice between basic (adding drain unclogger) and acidic (adding carbonated water). I figured that would be a neat topic for a video.

Pouring some drain unclogger on the blueberry juice, it turned green. I never thought of trying that before. Without a strong base, I was only able to change the acidity to mostly neutral, not basic.

More physics related articles:

Back to my Woodworking website.