lab 4

1. The students may have to work to see the Brownian Movement. Don’t let them give up :)

2. It is always a good idea to have the students start section 3 with the potatoes first thing. That way as they are waiting the 45 minutes for the potatoes to sit in the NaCl, they can do the other parts of the lab. After they clean their glassware, have them put the test tubes upside down in the rack with paper towels underneath. It will allow the water to drain before the next class arrives. Things have been going very well on the cleanliness aspect – Thanks! This one is the last really messy lab we have, so keep up the good work.

3. ** Filtration Exercise **

I have posted a modified procedure for the filtration exercise on blackboard. Please let your students know about the new procedure. I basically increased the amount of copper sulfate to use and changed the wood charcoal to some that is powdered (rather than the granular stuff that was there before). This should help things get dissolved and then filter out at the end. Please let me know if you have any questions about this.

4. Paramecium Video: Please refer to my previous email about posting youtube links and the two questions associated with the videos.

5. Feel free to use any of the live specimen for your quizzes next week – I have more if you need to use some. It would be good practice for their lab practical.