The Power of Demos

In order to increase students' understanding in Science, we use scientific models and demos. We've done a couple of demos lately that have really helped students to SEE what they have been reading in their textbook.

During the first nine weeks, we read all about how when water freezes in the cracks of rocks that it causes the rock to crack even more because when water freezes,

it expands. I decided to bring in a water bottle that had not been opened. Friends observed the water bottle and took notes in their journals. I then told them that I had another water bottle that has also never been opened, but I put it in the freezer. Friends made their predictions and then we observed the frozen water bottle and took notes. It was sooo much easier for them to understand what is means for freezing water to expand when they saw the second water bottle and how the shape changed!

Today, we did another demo to help us understand the density of different liquids. We had corn syrup, water, and cooking oil. We saw in our textbook that the corn oil settled at the bottom, the water settled in the middle, and the cooking oil settled on top. We made some predictions and decided to pour the liquids in random order and see if they still settled as they did in the picture in our textbook. We found out that they did! After great discussion, we came to the conclusion that the corn syrup has the greatest density, the water is less dense than the corn syrup, but more dense than the cooking oil, having the least density.

We then decided to drop three items into the liquids: a paper clip, square pattern block, and counting chip. Again, we made predictions about where these items would settle. The paper clip sunk to the bottom, the counting chip settled on top of the water but below the cooking oil, and the square pattern block settled on top of the cooking oil. We then realized we also learned about the density of the soilds we dropped into the liquids! The paper clip having the greatest density, the counting chip being less dense, and the square pattern block having the least density.

I loved hearing the, "OOOOHHHHH, now I get it" "I knew that's what would happen!" and "COOL!" :D