Monday, January 28, 2008

High & Elementary School

Last week my Honors class had the opportunity to share their chemistry knowlege with some 2nd grade classes. The goal was to show the younger children some official laboratory equipment, talk about what it was for, and to do a little experiment.

Since it involves pretty colors, I decided to have them do a little acid-base experiment using red cabbage juice as an indicator. Straight out of the (stinky!) pot, cabbage juice is purple. The students first needed to use beaker, flasks, and graduated cylinders to measure out 4 containers of cabbage juice.

Adding an acid to the cabbage juice will turn it pink. We tested 2 acids: vinegar, and lemon juice.

Next, they practiced weighing out solids on the balance, testing baking soda and salt. Here we see a student carefully adding the solid to the indicator in the beaker.

Bases (the baking soda) will turn greenish/blue as you can see in the picture below. Also note that we had the 2nd graders take copious notes during their experiment. (okay, okay, they filled in a chart!)

Of course, at the end we just "had" to combine all the containers to see what happened! Amazingly enough, the solution was purple! (Actually, that makes total sense - purple is neutral, and an acid & a base will neutralize each other. Just in case you were wondering!)

After a thorough cleansing of equipment & table, we were finished! Good times had by all. I think my favorite part was watching my students interacting with the younger ones - it was neat seeing even the gruffest teen acting nice & friendly.
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