Rotten Log Lab - Getting Ready

Getting Ready

  1. Find some nice, juicy, moss and mushroom covered, termite and beetle infested logs. You know you’ve found a good log if you can pull off chunks of wood with your hands. I discovered mine (8 logs, enough for my students in groups of 4) in a wooded area of Golden Gate Park. You can use the same log with 2 successive groups of students if you just make sure the first group doesn’t go crazy with the hammer. You can also flip the log over for the second group. I found that the best time to go log hunting is after a month of nice, wet weather after mushrooms have begun to appear.
  2. Make copies of the Rotten Log Questions
  3. Cover your tables with newspaper
  4. Set out logs and the group materials

Optional: Set up protozoa viewing station. I would practice extracting protozoa on your own first. The protozoa are active for around 2 hours before they stop moving so you’ll need to set up a new slide every few hours.

  1. To extract the protozoa, first find a termite and put it on a glass slide. Use one pair of tweezers to hold its head and the other to hold its rear. Slowly and firmly pull apart. You should see a long, stringy tube, the hindgut. If you don’t squeeze the rear end with the tweezers until you do.
  2. Place a drop of saline on the hindgut and mash the hindgut with the tweezers or a toothpick. If the hindgut never came out at all, you can mash the entire rear end.
  3. Cover with a coverslip.
  4. Observe under the microscope. Look for a mass of writhing stuff. You should be able to zoom in and observe individual protozoa and see differences between the many species that are present.