Wednesday, August 24, 2011

First class of co-op science

Some background:

We have 11 kids in the class at this point, ostensibly grades 3-5 although I think one of the boys might be younger. Whatever. Also, another boy can't be there the first 2 weeks.

The emphasis of the class will be in-class activities. To a great extent this decision is based on past experience that kids in this co-op really stink at remembering to bring in their homework; plus the onus of at-home projects tends to rest with the parents at this age, and most parents are juggling enough without worrying about their kid's bean sprouts, or whatever other project they're supposed to observe at home. That pretty much rules out botany

I'd like to get them thinking in terms of the scientific method. I'd like to give them experience in writing simple lab reports -- the type of thing they'll do in Apologia General Science and Physical Science, which are popular middle school choices for these families.

Last year's science classes were zoology for grades 3-5, and earth science for grades K-2. I have student from both those classes, plus some other families that just started co-op. Striking off in a new direction, we're doing physical science.

Okay, what we did the first day:

Discuss why we're studying science. (Quick pep talk about them being the future Newtons and Einsteins.) We're learning what those that came before us discovered, and we're learning how to make our own discoveries.

Discuss forming a HYPOTHESIS. Use example of MythBusters putting a Mento into a bottle of soda -- they had a hypothesis of why the soda bubbled up out of the bottle. I'm discussing this with a 12oz. bottle of root beer in a large plastic pie plate set in front of me, whilst waving around a Mento. MythBuster formed a hypothesis, had one VARIABLE and everything else was CONSTANT. (Words in caps written on white board while I'm talking.)

Throw Mento in bottle. Root beer foams up. One kid, J, wonders what would happen if we threw in another Mento. Since I already knew what would happen (nothing) I did.

Discuss what other experiments we could do with Mentos and soda. Attempt to get them to think of other variables. This was fairly unsuccessful -- I need to work on my technique for getting this age group to brainstorm. Since we are a group of strangers it's even harder. Anyway, I listed out several on the board -- bottle shape, soda brand (someone called out that Diet Coke is best -- we discussed briefly), temperature of soda, number of Mentos. Circled "number of Mentos" and said that consulting with my own kids we'd decided this would be the best one to do in the group, so LET'S HEAD OUTDOORS AND DO THIS.

Grab 4 2 liter bottles of 7up from my car (I didn't feel like dragging them to the 2nd floor and then back down). I also have Geyser tubes, Mentos, a portable white board, and some triangular cardboard sleeves I'd made to hold the soda bottle upright since the center of gravity on them is such that when you pull the strings of the Geyser tubes it's entirely possible that you'll knock over the soda bottle and have it spewing out sideways.

I explained that we were using regular 7up because that's what Walmart had on sale.

We set off 2 bottles simultaneously -- one with 3 Mentos and one with 7 Mentos. I had the kids load them, but pulled the strings myself since it's nearly impossible for 2 people to pull the strings at the same time. Also, I left the top caps off of the Geyser tubes because the caps make so much back pressure that the soda squirts out the sides of the tube -- fun to watch, but we're trying to compare height.

The bottle with 7 spewed nearly twice as high as the bottle with 3 (NB: at home we tried setting off 3 bottles at a time, and it was almost too much to look at so quickly, thus the decision to only use 2 bottles at a time). The bottle with 3 went about as high as J is tall, which was easy to see since J pretty much refused to move out of the way with everyone else. I drew the relationship on the white board, noting that sometimes in middle school Apologia they'd have to draw what their experiments look like.

Then I said we'd set off a bottle with 7 Mentos and a bottle with 11 (11 is the most Mentos that will fit in a Geyser tube). One of the kids suggested that it would've made more sense to set off the bottles on the base of the volleyball-net poles. Wow, I hadn't thought of that -- we discussed pros and cons, and then switched over to setting them off there. The bottle with 11 didn't shoot off that much higher than the bottle with 7. I drew it out, explained that people have tested every single number from 1 to 12 and graphed it, and 7 seems to be the optimum number due to diminishing marginal returns (fairly obvious they hadn't heard that phrase before, although we use it at our house all the time).


Next, I commented, "You know, these Geyser Tubes come with all sorts of different shaped caps, and they claim that they spew out different shapes. I'm not sure if that's true. You want to see if it works?" Head back to my car to get 4 more 2 liter bottles, this time the generic diet cola from Walmart (which, by the way, didn't spew as high in our backyard testing). Set them off 2 at a time, this time with kids setting them up, pulling strings, whatever they want to do as long as they take turns. The soda spews out the sides of the geyser tubes as well as the tops. J stands in the fountain made by the sodas. We don't see much difference, except the one with 3 holes in the cap really does look more like a fountain.

By this time I've had B ask about a dozen times "Can we eat the Mentos?", and in spite of my assurances that the soda is nasty to drink with the Mentos in it, several kids want to try it. Looking at my watch (yeah, I now own a watch, purchased just for the occasion) I say, "Okay, let's go into the kitchen and see if we can find any plastic cups." The rest of the hour was spent sampling soda with Mentos, as desired (some kids wisely declined), being horrified that I was pouring the soda down the kitchen sink (how could I throw it out?) while trying to keep the Mentos left in the bottles from going down the sink ("picture if we plugged up the sink and a plumber had to come, and said, 'hey, your pipes are plugged up with all these Mentos!'"), washing off the stickiness of the day, then sending them on to their next class.

Overall, an okay class. J was appalled that I had purchased Geyser Tubes, saying you could make your own, and sort of designing it on the fly as he was discussing the concept. I suggested that he make one and bring it in next week -- I'll supply the soda and Mentos if he'll supply his design. I think J is going to be a lot of fun to teach. I'm sure the other personalities will begin to emerge over the next few weeks.

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