Tuesday, October 2, 2012

getting the ball rolling

jen's daughter had a bowling party to celebrate her birthday earlier this year.  while i enjoyed the bowling itself, i couldn't stop myself from thinking about how cool it would be to investigate principles of physics at a bowling alley.

i mentioned this to jen and another homeschool friend who were (thankfully) game to give it a shot and allowed me to lead a science lab.

i envisioned having two lanes side-by-side to try some experiments, but we had only one lane.  i'm so glad it turned out that way, because we were able to do some really, really cool things that we might not have otherwise.

we sat on the floor and talked just a bit about newton's first law of motion (which, in our house is translated as "an object at rest cannot be stopped") by observing the speed of a ball sitting still.  i particularly loved the fact that all three kids noted that the speed was zero, not that it did not have any speed.  we noted the motion of the ball when is was acted upon by a force, such as a younger sibling.

we set up some controlled conditions.  i told them to ignore the scores and the number of pins being knocked down - we were concentrating on the ball today.  each child selected a different weight of bowling ball.  two kids sat and held the ramp in place while the other set the ball at the top of the ramp and gave just enough of a push to set the ball moving.  then they all watched the motion of the ball down the alley, taking turns rolling.

after that, they were ready to throw, so each of them picked another ball and tried to throw it in as controlled a motion as they could.

this was particularly interesting, as they noticed all sorts of things.  gutter balls happened way more often - they realized that trying to control the motion of a heavy ball is fairly difficult.  faster throwing speeds often resulted in poorer directional control.  slow rolling might not be as exciting, but it consistently produced a straighter, more accurate roll.

we took the time to check out the differences in surfaces.  they all knew that friction contributes to the slowing of ball motion; that's why carpet is not ideal for rolling.  we also compared the smoothness of the lane vs the approach - they could feel the waxy difference (which i have since looked up and learned is oil, not wax).

we saw how the gutters really slowed down the speed of the ball - to the point where one of the balls stopped completely halfway down the lane.  time for an awesome idea - throw another one down the gutter and observe the law of conservation of momentum at work!

we set up the ramp again and the kids instinctively held on extra tightly when i asked them to push the ball down with as much force as possible - that got a lot of cheers as the balls went whizzing down the lane!  talk about observing the effects of mass and speed!

one of the kids noticed that the ramp moved backwards when not held carefully in place while the ball rolled down (evidence of newton's third law), so we made a whole other set of observations by trying different weights of different balls and different rolling forces and comparing how far the ramp moved back when held vs. not held.

i also had them take a look at the different kinds of motion the balls made when rolled slowly or thrown forcefully.  we watched the spinning and sliding.  they each fixed their gaze on a point on the ball and tried to see that point show up again and again as it rolled down the lane.

we talked a little about potential energy - they had all heard of "stored" energy and gave some pretty accurate descriptions and examples of it but were not as familiar with the term "potential" - they got the connection, though, when we discussed what we observed with the balls starting up on the ramps vs. down on the floor.  we touched just a little on the conversion of potential energy to kinetic energy, but by then their bodies needed to be a little more kinetic - so we just bowled for fun!

i was really impressed by how much they got into this lab.  i worked very hard to talk little, just enough to introduce a concept, give them something to focus their initial observations on, suggest something to try.  they took off with it, instructing each other, drawing each other in, cooperating, noticing and sharing, expressing their mutual excitement over trying things out.

the moms gathered data (time-taking) and i recorded it for the kids so they would not be interrupted in their process.  i wanted the kids to be familiar and comfortable with the idea of making observations but not get bogged down in the important, yet separate, process of data collection.

we were all so involved that i didn't get many photos.  i wish i could have had a video of the time that the kids rolled a 15 pound ball down the ramp with such force and accuracy that they got a strike - their enthusiastic cheering rang through the alley!


on the way home, i asked diana if she had learned anything new.  the concepts were mostly a review for her, as we had taken a dive into energy already via rs4k and made a marble run to try out some experiments, but she really liked being able to feel and observe and investigate the principles in a different and another meaningful way - and with friends who are similarly turned on by science.

i am happyer at home because the world - complete with bowling alleys - is my classroom.

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