Today was a lecture day. I have found these to be occasionally necessary. The benefits are that a relatively large amount of information can be presented in one day. Whether that much information can be assimilated is another problem. I have also found that people tend to think they understand something when they have only heard it, and they have a harder time picking out what they do not understand. When they must use it (or in this case are tested on it), they suddenly find it does not make sense to them.
I think I have many temptations to lecture too much, especially at this job. For one, I have a tendency to enjoy the sound of my own voice. I have been trying to address this for most of my life, and although I listen better and talk less, I still have to be very careful and I still have a long way to go. Added to this is that my current students are very comfortable being lectured to. It is in their comfort zone. The teacher tells them what is true, perhaps they write it down, perhaps they do the homework, and then they are asked to recall it. In my other school, the students would get very antsy if anyone lectured more than one day in a row. Their desire to be more active was very helpful in keeping a teacher accountable for varying the classroom activities.
All that said, today was a good day to lecture. I spent last week doing a lot of conceptual, visual, and hands-on things. I ended the week introducing the first gas law equation. Today I did three more. Fortunately the math is fairly easy for these students, so I am interested in helping them use the right relationship at the right time. I don’t need to teach them how to cross multiply, but I do need to teach them how to understand a question.
Tomorrow we will review for our upcoming quiz. How I love a quiz. So much information, so few points. So much less stress from the students. If only I could call the final exam “a little quiz to see how you’re coming along.” Anyway, I have a table comparing/contrasting the gas laws for them to fill out. It has a column for the demonstration that goes with each gas law. I hope this will help the less math oriented students figure out which relationship to use.
Boyle’s Law: the bell jar vacuum
Charles’ Law: balloon in freezer, and imploding pop can
Avogadro’s Law: blowing up a balloon.
Gay-Lussac’s Law: sucking an egg into a flask, and the nitric acid/copper demo.
I am hoping this is the only all lecture day this week. It should be. At some point I will do a mini-derivation of the ideal gas law (following the ChemTeam).
I am hoping to do this lab. Pretty standard, but I don’t have time to find something else in the gas laws. Plus, I did this lab while student teaching, so it’s not completely new to me. I don’t really feel the need to practice it, for instance. I plan to use this procedure to measure R, not to find the molar volume. I’m not going to go very deeply into molar volume.
