Ch Ch Changes
To get us in the groove, we investigated some physical changes like dissolving one substance in another. To show that a physical change means the change can be undone, we made rock candy, The kids did all the work, measuring, pouring, stirring, all the while thinking and making connections. They saw the sugar disappear and the water become totally clear again. One of the neat moments was when one of the children pointed out how much the level of the water had risen. Then we saw how the sugar comes back out in the candy.
Then we made glue. Did you know you can make glue from vinegar and milk? I certainly did not before this year. It is similar to the process that the Ancient Egyptians used to create glue from the bones of their kills. We got the experiment from our text but Zoomkids also has a version. There are two different chemical reactions within the experiment. The first is when the vinegar separates the curd from the whey in the milk. The kids were amazed to watch the curds form. It was very easy to see that it could not go back to milk. Then you add the baking soda to the curds and the second reaction occurs forming the glue.
Then the children had tons of fun creating collages with their own glue. It was tons of fun.