Friday, February 23, 2007

Fossil synchronicity. Electricity (again). Gravity (again).

A student brought in a nice chunk of petrified wood to show around. Interesting timing, because I had chosen today to bring in my favorite Ammonite and Trilobite fossils. So we had a good ole time sharing fossils. Actually the Trilobite fossil technically belongs to my daughter who was somewhat territorial about letting others touch. That works okay for me, because as a class we are trying to learn to "look with your eyes, please, not your hands". It is terribly difficult but we are beginning to manage it. Trilobites are pretty cool. They were wildly successful all over the earth, possibly because they were the first critters to have eyes, which must have given them a fabulous advantage over everybody else. Unfortunately things got rough for them when some fish showed up with the first ever Big Sharp Teeth, and – well - that was it for the Trilobites. Three hundred million years at the top of the heap, and then - - pfffft. Sic transit gloria mundi.

Last week (which didn't get blogged due to post 'flu fatigue), we actually devoted almost the whole Discussion Portion to . . .
Leeches
Interesting surprise. One among us wanted to know how leeches eat, and the topic proved irresistible to one and all. Can they see? Can they smell? Where do they live? Do they live in Texas? (hint: yes). Unfortunately the library (which until now never let me down) is very weak in its selection of Leech books. I have, however, hunted down a couple good ones elsewhere, and will bring them in next Wednesday.

I don't seem to be able to get away from this electricity demo with the portable car starter battery and light bulb. Somebody wanted to know does salt water conduct electricity, and I cobbled together a lovely demonstration showing how brass and steel and copper all conduct electricity, and wood and plastic don't (the light bulb comes on when you have a good conductor). But when we got to the salt water - - fizzzle - - the current was too weak and the bulb didn't go on. That was last week. So this week I brought in our friend Mr. Multimeter and we could see the relative amperage levels when passing current through copper versus salt water, but after class I realized I had never got back to the original question which was salt water versus plain water. So I think the same apparatus has to come back one more time next week for another variation. In a way this is very instructive, because at least 75% of all experiments are miserable failures the first few hundred times you try them, and it really does take a bunch of tinkering to get them to show good results!

By the way, I do emphasize a good deal about safety and protective eyewear and Do Not Touch Certain Things, but a little home enforcement would probably not hurt. Something like, "No, honey, you can't go to the garage and take the taillights out of the car and hot wire them to the battery all by yourself. Let Mummy help you with that".


There was a pretty good sidebar on gravity, too. Apparently the question of No Gravity in Outer Space has been hotly debated ever since Deborah's spectacular Story Of The Universe show. A week ago I talked about gravity quite a bit (before we switched to the All Leeches All Day channel). This week one of the kids who had been out last Wednesday asked about gravity and outer space all over again. We all agreed that we'd already talked about it, but - - did we all get it? I don't think so. So it's good that the student opened an opportunity for a little repetition. From the responses I got it seemed the idea was sinking in better this time.

I like all the concrete and informative stuff, and I like how children catch on to things we know and how we learn them, but I have a certain special fondness for the real mind-bender questions they offer up with such generosity. Such as
"What would happen if you tried to push the whole universe?"
(My answer: "Before I try to answer: if you are going to push the universe . . . at the moment you are pushing . .. where are you?" You could see in their eyes. They totally got it. It was a hoot)

Looking at each week's new cards in the Question Box, I notice a dramatic improvement in the writing and spelling on these cards compared to last fall. How cool is that?

Sunday, February 11, 2007

Bricks, Blood, Bulbs

 The Question Box contained a whole heap of Question Cards, all in the same handwriting, all beginning with
                How do you make
Clearly somebody was on a roll with these. I chose to share
                How do you make brick  
because of the  convenient tie-in with art class (where they were talking about clay and kilns just last week). This could have been a really short Q&A ("How do you make brick? You take clay. You bake it."), but trust our kids to find the leaks in any presentation. Hold on a second: I saw clay in art class. It was gray, not red! From here: yellow clay, red clay, iron oxide, Mars, . . .

Also in the question box was the scientific and poetic query
                Does your heart still beat when you don't feel it
which the class enthusiastically answered without my help ("if it didn't, you would be dead!"), and which led to a vociferous debate on the velocity of blood, and a wide-open opportunity to talk about the circulatory system. So, it's clear what I need to drag in from the library this week.

The demo/presentation for the week consisted of a genuine working electric circuit (battery plus lightbulb. As it turns out, I DID have a good reason to save all those old auto taillights in the box in the corner of the garage; I just didn't know it at the time). In a burst of either creativity or outright silliness, I asked the children to take part in a live action simulation drama in which they, as actors, played the part of copper atoms and had to pass a bunch of electrons (styrofoam balls) around the circle. Perhaps you parents can act the part of my Cognition Spies. By gentle and subtle interrogation, you try to find out whether that little masquerade had any impact. The child's state of mind could be something like
- yeah. I totally got the idea because it was so vivid this way
- he explained about a circuit, but trying to BE a circuit was a little overdone
- we played a game with styrofoam balls. I wonder why.
- science class? was there science class last week?

Three Points of Protocol

Just so you know, here are three things I constantly ask of the children.

1. Any time you have a science question during the week, write it on a card and drop it in The Question Box. Of course this can include questions you asked at home as well as at school.
2. Did you make any astonishing discoveries during last week?
3. What would you like to see or do for a weekly demonstration in the future?

So far, they have been generous with responses on all three. By all means encourage this.







 

Sunday, February 04, 2007

Rocks. Who knew?

This week’s demo: grading the hardness of minerals using the traditional scratch test.

Examples:

Talc cannot scratch quartz, but quartz can scratch talc

Quartz cannot scratch diamonds, but diamonds can scratch quartz (etc)



I figured after all the excitement with fires and fizzes in recent demos, this one might achieve a collective yawn. Not so: everybody seemed fascinated by the idea. The more tests I did, the more the voices rose “now try the sandpaper on the steel! Now try the limestone on the chert!”. Scratching rocks together: who knew? I remember coming into class with high hopes about the size-of-the-solar-system demo, only to find practically no resonance. It’s easy to infer a simple rule such as that lessons are better “if I can touch it and see it”, but that doesn’t explain their excitement about imagining what is a googol, or how many molecules in a teaspoon, or the habits of pangolins.



As the year proceeds, I flatter myself that I am gradually improving my basic classroom-control tactics. Of course I don’t have the Black Magic Secrets that enable certain Montessori teachers (hint: first initial "D") to whisper “Children: Quiet” and bring a roomful of tornadoing screamers to a sudden frozen silence and rapt attention, but still I fancy the class is doing pretty well at remaining focused and seated in circle. Which brings up our little mini-anecdote: I had brought in a pair of safety glasses (“always wear these when breaking rocks with a hammer”). Just as I was congratulating myself on my Well Managed Group, one boy [name omitted] puts on the safety glasses: then, apparently fancying himself to be something like Bud The Spaceman with the glasses on, he takes off at about 100mph on hands and knees, giggling wildly. At this point two others pursue him (surely planning to restore order by open-field-tackling the perpetrator). For a moment it looked pretty dicey. I did manage to get everyone back to circle fairly quickly, but it was a good reminder about how close we are to the edge at every instant.



Questions from the Question Box included

How big is the world’s biggest tidal wave (I don’t know, so I dodged into How Earthquakes Make Tidal Waves and Tsunamis Is Another Word For Tidal Wave. I thought it would be dull to get into measuring tidal waves by height, mass, distance of dispersion …)

How thick are your teeth? (I didn’t know, so I brought in a digital caliper/micrometer the next day. Incisors are 3mm thick and molars 12mm. I am sure I looked pretty comical jamming a caliper into my face).