3rd Grade Group
Last week we learned about physical changes, so this week we learned about chemical changes and chemical reactions. We did two activities with baking soda and vinegar. For the first activity, we combined baking soda and vinegar to watch their fizzy reaction. The second activity used purple cabbage juice as an indicator of acids and bases. We added the juice to vinegar and saw by the color of the mixture that vinegar is acidic. Next we added baking soda and watched as the mixture changed color, indicating that the mixture was now basic.
4th/5th Grade Group
This week we learned about surface tension. First we went outside to do a trick with water. Because of surface tension, we were able to turn a cup of water upside down without any water spilling out! For the next activity, we poured milk onto a plate, and then added a few drops of food coloring. When we added a little dish soap to the mixture, the food coloring in the milk began to magically spread and swirl into beautiful patterns! We learned that because milk is full of proteins, adding soap will change the proteins' shapes, which causes movement in the milk that we can see with the food coloring.