Tuesday, April 17, 2012

Simple Machines for Preschoolers

Child-led learning. It all sounds so lovely and peaceful. But really? I end up using child-led inspiration for our activities when the kids are at their worst, when nothing I do can stop the cycle of twin-on-twin aggression, when everyone is too tired or sick or grumpy to concentrate on what I planned.

Alex and Anya were having a bad morning, switching off roles of tattler and mischievous imp, with increasing escalation and contrariness towards each other. Alex shouted from the living room, "No, Anya! Don't stick that in the couch! Mama, Anya won't stop and she's ruining our couch!"

When I got to the living room, Anya was scowling at Alex and mumbling something about a lever while gripping a long skinny paintbrush. She had been shoving it into a hole in the couch so she could make a lever to push and pull.

Things were getting dire. I needed something to distract them. Science to the rescue!

I asked them if they would like to learn about levers.  I took the paint brush and showed them how moving the whole thing moved it only in one direction, while if I balanced it on a Lego, I could push down on one end and watch the other end rise. I introduced the idea of pivoting, and that there was specific point at which the brush pivoted, which is also called a fulcrum. We looked at some levers around the house, like scissors, and I had them identify the pivot point.

I looked around for a quick and dirty way to show them the difference in the amount of work that it took to lift things with a lever and without. We had an old box filled with Playmobil parts, and I duct taped the trusty paintbrush to the bottom of the box and had the children lift it straight up. Then I had them add in our Lego fulcrum again and try pushing down to lift it up. I described how when we did it the first way, our muscles did all of the work, but in the second way, the lever did some of the work, meaning less work for our muscles.

I asked them to think about if we would be able to lift more or less with a lever. I asked them if they could think of any outside toys we had that were levers. They struggled with that question a bit, so I asked if they could lift each other up in the air- which backfired, because Anya can totally lift Alex- but then asked if any of their outside toys made it easy for them to take turns lifting each other up in the air. I sat in front of them going back and forth with my finger on a pencil lever held over a Lego fulcrum, and eventually they realized that see-saws are simple levers.

Since Anya's desire to push and pull levers was the start of all this, I gave them plenty of time to play with all our improvised levers and make some new ones of our own- though I did convince her to avoid poking more holes in the couch to do so.

Next we moved on to ramps, which were much easier to grasp- perhaps I should have started with them? I demonstrated how a little car needed me to push it on a flat board, but would move on it's own down a ramp, again emphasizing that in the former, my muscles had to do the work and in the latter, the simple machine did the work.

I was hopeful that if I set them up with a good ramp that I could take a kid-break while they explored. I love doing these projects, but I think we all do better if I can have plenty of downtime between projects!

I grabbed the remains of the (poorly constructed) dollhouse that I built for Anya a couple of years ago and duct taped two boards together. One side we propped up in the couch, the other was to let the cars run on after they built up speed on the ramp. I was going to have them measure the length that each car got on the board, but all of them went much further, so I settled for giving them a piece of tape to mark the farthest any car got on the rug a couple feet out from the ramp.

They tried a ton of different small vehicles, and seem to realize quickly that the cars with motors never built up speed- we had a good but brief talk about how those cars are designed to go forward powered by the motor, and that the wheels could not move freely with gravity, like simpler cars could. I did have to remind them to not fling the cars down the ramp, but rather than phrasing it as a rule, I explained that we were measuring the work that the ramp was doing, and that if we used our muscles to propel the car, we wouldn't be measuring just the work of the ramp.

They also experimented with pulling the ramp farther out or pushing it in, changing the angle, and the behavior of the cars going down it. Very cool to watch them exploring!

Eventually Anya started wandering off, but I thought we could milk the ideas I had introduced just a bit more. As we were walking to the backdoor, I asked them to look around for more levers and ramps. Alex, who was still very into rolling things down ramps, went flying over to the fridge and announced, "Ramp!" proudly at the magnetic marble run. Yay!

Anya and I went ahead outside while he played and Anya peered around and told me in that condescending preschooler way, "Now, Mama, the slide, right here? That is a ramp, Mama, did you know that?"

She also decided that the rocking horse was a lever, pointed out the see-saw to me, and told me that we should use a ramp to get the snowballs on top of each other for a snowman.

Science FTW!

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