We already finished with all the water experiments. Besides this post, I have two more to publish. I hope that by sharing them here, others can find ideas for their own water units.
Above you can see the kids preparing the water for our experiment. They needed to make green water for our air temperature sample, and blue water for our cold water sample.
Once the blue water turned icy, we compared it to the air temperature water. We were able to see condensation! The sweat outside the cup was our sign. The kids touched the "sweaty" cup to discover it was coming from the water in the air outside of the cup. The water vapor in the air (a gas) touched the cold cup, and it became a liquid again. The condensed water was not blue, hence it proved to us that it was not just water leaking from the cup.
We noticed that the air temperature water didn't have any condensation.
Next the kids prepared a condensation chamber. They added 50 ml of the icy water to a dome lid, put a cup on top, and left it to rest by our sunny window.
This is what we found out a couple days later. The water had evaporated. As it touched the cooler sides of the cup, it condensed, and became water again. It is a whole water cycle in a cup!
The kids also figured out that water evaporates to its pure form, hence the blue coloring was left behind. All the water droplets were clear.
I opened the chamber for them to explore the water droplets.