Microscope, Mushrooms, and Mythbusters

I brought in that TeeVee again. I think it's working really well as a way to help the students learn how to focus the microscope. Earlier this year I had a couple sessions that seemed fairly futile, to the effect of
Me: is the picture clear?
Student: I can't see.
Me: Here, let me put your hand on the focus wheel. Okay now turn it gently.
Student: I can't see.
Me: Try turning it a little more?
Student: I can't see.

But - - when the microscope image is transmitted onto a 20-inch TV screen, Ta Daa!
Me: Who would like to be our focus wallah?
Student: I would.
Me: Okay, turn that wheel. . . gently . . good. . . little more. .
Student [turns wheel]
Me: Can you see the picture is getting clearer?
Student: Yeah!
Class: Oooooh.
Class: Now let's look at the sandpaper!
Me: Who would like to be the next focus wallah? . . .

I brought in some genuine caliche (you know, the nasty limestone-clay crud under your lawn).
Hope #1: It would look interesting in the stereomicroscope. Well. Sort of.
Hope #2: By suspending some silty particles of it in water, we could look at them in the compound microscope. This is the part where I find out that getting the compound-microscope image into the TeeVee was much trickier.

Okay, the caliche was sort of a dud, but the teensy little twig with neat fungus found by a student was anything but a dud. Each of these little mushrooms is, oh, maybe half a millimeter high:









Back to the "dud" theme: I had heard the wild rumors that "Mentos and Diet Coke explode!!" so, I figured why not play MythBusters in class a little? Do they really expLODE?
Experiment.
Result.
If you put diet coke in a beaker, and toss in a Mento - - it - - uh - - fizzes a little bit.
Myth: Busted.
(after the fact, I YouTubed around a little to see what is the real story. Yeah. Mentos cause the CO2 to come out of solution. Y'know what? Salt does that too).

Cartoons! Butt jokes! The Spice Must Flow!

The arrival of a TeeVee set in class provoked loud excitement. Will we be watching Spiderman in science class? Well, no, but watch thiiiiiiiiis: with a digital camera, you can pick up the image in the microscope and transmit it to the TV screen. Here you see some crystals of ordinary table salt, and a little drop of water:

(the actual image inside the microscope is MUCH better than its blurred, low-resolution version on the tube)

Even though a lot of the adrenaline in the class was a response to the technological novelty (plus Spidey), I fancy that some hint of the intended idea made it through, i.e. a little more publicity for our friendly neighborhood microscope, a little more astonishment at the things you can see if you only look closely.
Also, I've noticed that focussing the microscope can be difficult for a 6 year old. With the image on the big screen, I can participate as the child struggles with the focus wheel. "Keep turning. Do you see, it's starting to get clearer? Sloooowly now . . . a little further". With luck this skill will still be there later when the child works the 'scope alone.

I never actually got to show off what I had discovered by accident at home. If you put a water droplet on a plastic dish (so the droplet beads up), and very gently push a sugar or salt crystal up close to it, there is a point where the crystal suddenly jumps from outside the water to inside. I suppose it's related to surface-tension. It's quite startling. Try it in your home stereomicroscope. I like it as an example of "who knew such weird things were going on right under our noses." (In class, with the TV turned around to share, resulting in Left::Right reversal, I couldn't quite summon the hand-eye coordination to show off the jumping-crystal phenomenon).

A helpful class member brought in a slice of skin - - a mole removal, I think. It had been cut, we are told, from Daddy's Bum. Good timing, that the TV was here today, because we could all see the Bum Skin Chunk under the microscope together (it looked a little like tripe). I might have done more – cross-sectioning, making a high-magnification slide, etc – but I wasn't quite clear as to whether the doctor needed it back, or whether it had to be kept in its formaldehyde, or what. Certainly it won plenty of attention. Perhaps there was more excitement about its being Bum Skin than about Fascinating Tissue Structure. Still, just like Spidey and the microscope, the flow was all in the right direction anyway.

As a followup to the week-before-last, I brought in a couple of leech books. I loved seeing how the original Leech Question Asking Kid grabbed that book like the gift-of-the-month and dove into it.
I learned that your typical Medical Leech has teeth - - lots and lots of them. (It uses them to shred your skin so The Blood Will Flow. Its saliva contains a good dose of anaesthetic, so you never feel a thing). The photograph in the book, though, was interesting, because all the sudden I knew exactly where David Lynch got the idea for those sand worms with their frightful snapping jaws!

Yeah. Leeches look like that. You must not fear. Fear is the mind-killer.

Finally, thanks to the dizzyingly insightful child whose question-box card asked

How are water molecules made ?
allowing us to have fun with the molecular models kit, illustrating the burning of Hydrogen in slow motion.


No class this week (field trip)
No class next week (spring break)
Thank you for sending us your fascinating and fascinated children.