All rights reserved. These last two days, my classes have observed what happens when you add a drop of food coloring to the top of a glass of hot water vs. what happens when you add it to the top of a glass of cold water. A few students in each class came up with VERY imaginative hypotheses, after I urged them to be creative, saying that's what scientists do when they try to figure out how the HIV virus gets into white blood cells, for example. One student shared that the hot water was heated, sterilizing the water, killing the bacteria in it. They did all become very attentive when people were explaining their ideas, so I think there probably is potential for continuing with this.
Chlorine works better in warmer water.
I'm looking forward to your ideas. The only trouble I see is that you are working with something that is occurriing on a molecular level, and therefore is impossible to observe directly. I assume you want students to arrive at some sort of kinetic model. The first issue the students must confront is how to actually test their idea. If an idea can be investigated, then it is a good one to work on.