Solutions

Solubility and Models

First, I had my students examine the conductivity of a puddle of water the size of a nickel. They checked for conductivity. Then they took a very small amount of sodium carbonate and a fresh puddle of water and pushed in a few crystals from the side.  You can still see the crystals in the water but it tested positive for conductivity. They had to explain this. They did the same with a fresh puddle of water and a few crystals of copper (II) sulfate. Again, it tested positive for conductivity but they could still see the blue crystal. Finally, they started again with another fresh puddle of water, pushed a few crystals of sodium carbonate on one side and on the opposite side they pushed in a few crystals of copper (II) sulfate.  After waiting five minutes, a solid dull blue precipitate formed in the middle.  Also, the drop tested positive for conductivity. 

Thank you "Lady from Texas"

At Chem Ed 2015, a teacher from Texas showed me this quick and dirty way to do a distillation that the kids can do. I forgot her name. "Lady from Texas", let me just say "thank you". If you are reading this, please shoot me an email and I will be more than happy to give you credit. It worked really well.

Fun with M & M's

This simple, yet interesting experiment that was first described by Elizabeth Sumner Walter in 2001. She merely had students pour water into a dish containing some Gobstoppers candies.