When they come in I give a very simple quiz which we do using clickers, the sort of anonymous audience response systems, and I just test a few multiple choice questions, just testing their understanding of some of those terms and then when I notice that there’s, well, anything more than 10 or 15% of students who don’t correctly understand those terms then we go through a process of exploring what those terms are and why they apply to what they apply to and then I retest that a couple of weeks later....
I guess what every educator deals with is needing to find out what preconceptions there are at the start of the unit and then correct those and then keep on top of those throughout the course. For example I get students who use the word particle and the word droplet interchangeably.
Put a bit more emphasis on the physical state of the substance that they are learning about. Because students often aren’t really able to imagine what kind of substance they are going to learn about. They will then know that they don’t have to calculate the volume if it’s a solid, for example, they have to calculate it by mass.
Use demonstrations when teaching about solubility. Students need to be thinking about what's going on. You have two clear solutions and when you mix them together a white precipitate forms instantly. Then decant the liquid and get them to think about what’s in the supernatant and what is the solid. Go on to use calculations to work out the solubility for an amount of substance. Use the amount that you can see as a precipitate to work out how much is in a saturated solution.
