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!