Nematode mania

Maybe somebody got a little tooo charged up about those nematodes. I came in armed with

• as requested by the class, etymology of the word nematode ("nema", thread: hence, "threadlike things"
  
• a dozen amazing nematode facts courtesy of UCal Berkeley via the www
  
• nematode anatomy information: musculature, neurophysiology, cell layers
  
• Electron microscope images of nematodes
  
• cross-section diagrams of nematodes at various points
  
• a box of actual nematodes from the garden store, plus microscope to look at them
  
  
  
  
• some actual grubs from my back yard, for an experiment, to see if the nematodes from the garden store will eat the grubs as advertised
  

Well, nobody complained about too much nematode content, although I fear the focus may have faded a bit by the end and I am not entirely sure how many of the class quite grasped that there was a controlled experiment being launched. I'm writing from on the road here so I haven't had a chance to check back. Like all real experiments, this one has a good chance of giving muddled and illegible results: like for example if my trusty helpers don't remember to water them and the grubs just all die of thirst whether they are in the "with nematodes" beaker or the "no nematodes" beaker.

As far as K class, I was even tempted to bring them a few hundred thousand nematodes too. Then I reflected, they haven't even seen The Invention (see post from a couple weeks ago), and we could have a pretty good thrill just looking at sugar and salt crystals in the stereomicroscope. Which we did.



The Question Box was so stuffed they hadn't even been able to cram more Question Cards into it! Is this a fabulous gang of kids or what? I emptied the box, and am saving the cards for posterity. I wonder if I can get these things bronzed.



No class 14 Nov (due to my travel) or 28 Nov (ditto).

Marbles, voice, creative thinking

Ever since one student asked in August "just what is electricity" I've been puzzling about how to make a demonstration. This week I brought in electricity demo v2 (version 1, in August, was really no good at all). In v2 I have routed out a shallow elliptical channel in a 2x12 wood plank. I load the channel with marbles, while explaining that copper atoms
(a) unlike hydrogen atoms, have a whole lot of electrons (29)
(b) are willing to share with their neighbors.
Then I claim that this heap of marbles shall represent electrons, and I kind of swirl them along so they go around the track.
I don't know.
Everybody was pretty nice about going along with it, and nobody complained. I feel like taking a survey

As to that demo - - would you say
(a) Wow! I like totally understand electricity now
(b) I guess there's sort of a connection. Thanks for trying.
(c) Can we play marbles now?

The creative input from the younger members of Team Science was superb. The question box in K included

What does the inside of a tree trunk look like

which is just the perfect question to ask of a guy who has arrived in class lugging a huge section of 12x2 pine ! Not only did we have the chance to discuss annual rings, but the various surfaces on the plank offer an interesting lesson in 3D geometry, if you try to realize that the straight lines on one face have a connection to the circular lines on another face.

I have to bring that plank back in and leave it for closer inspection.

Over in Silver Surfers it was a pretty busy class as we had a repeat of the electricity marbles, plus a discussion about nematodes (there are a lot of them. everywhere) (yes, they are really tiny. and that imposes serious constraints on their complexity. No eyes, nose, mouth. No hands, arms, heart, lungs. No brain!). The discussion was very lively and I had to cut it off because I was eager to cram a third item into the agenda. But I will be back with more nematode mania next week.

Following up on a question about how voice boxes work, I brought in a sound-making device consisting of a piece of dried plant stem and a brass tube. The idea was to show that the mouthpiece alone makes a plain squawk (just as your voicebox makes a plain undifferentiated noise) and the brass tube allows us to refine and shape the sound (just as your mouth shapes the voice into speech sounds). Fortunately one of our creative thinkers caught me before class and said "are you going to play a Halloween song on that thing?" and I said, "Can you tell me please what is a Halloween song", and so she hinted at one, so later I did exactly what she said and that turned a simple science demo into a great big classroom hit! Thanks!