Friday, November 13, 2009

Velocity of a Marble: Results

Here is the much anticipated result of our marble investigation. I was delinquent in getting pictures to go with my results. I have to have the pictures! If you missed the first post on our most excellent math lesson, then go to there and read about it. It was good science!!

The first thing the kids found was that it was hard to get the marble to repeat a good run enough times to record it for five trials in a row. They tried to get the marble to go around the curve correctly each time to no avail. Finally, they ended up making a new chart to record the partial runs. We could calculate the velocity whether or not the marble went all the way to the end of the track.

The data chart-we recorded the time in seconds using a kitchen timer. Each of them took a turn helping to hold up the part of the track near the curve, timing, and letting the marble go.

Then we measured the length of the track at both the partial and final marks and I marked the yarn with the start and partial distance. That was important later on. E11 used a yard stick to record the full and partial length of the track. Then we had the mathematical task of converting the measurement to inches. Note, scientific work is generally done in cm, but I was working with a yard stick not a meter stick so I just went with English measurements this time.

The final calculation page. E11 and R9 used the formula velocity = distance/time to get their answers. The answer was in inches per second. Their marble was traveling 41 inches per second down the marble track.

Then I thought I'd give E11 the challenge of converting our answer from inches per second to miles per hour. That was fun! Yeah...I'm that kind of mom!

Some things to think about- first the kids wanted to give up on the full track runs, but I made them stick with it. E11 was especially annoyed and declared it was all ruined several times, but I reminded him about how scientists meet up with obstacles all the time. Dan helps to manage a university lab full of users who get frustrated the same way. Months of work will come to a crashing halt when they make a mistake or a tool is dirty and ruins a wafer or a tool is broken and breaks something they've worked hard on for a long time. There is a delay in forward movement. They have to begin again. That's how it is in the real world of science! Besides, E11 is a very bright boy who needs to work on perseverance when something is more difficult than he would like to battle.

Also, before we could do calculations, we had to deal with the raw data. We chose to find the median rather than an average in order to do the velocity calculation.

We had trouble importing the video from E11's camera into Picasa so for now the video of the run will wait. Next time... Aha! E11 just informed me that his camera card was not wiped so perhaps, with my help, we'll load up some video for you. That was part of the challenge that day.

All in all a fantastic activity for math and science. I wonder what we'll do next!

Anonymous said...

I've noticed it before but can you tell us what it is you have covered your table with? Is it a timeline?
becky

Heather said...

Becky it's the Amazing Bible Timeline that I reviewed for the TOS Crew. http://blogshewrote.blogspot.com/2009/10/tos-crew-review-amazing-bible-timeline.html

I can't seem to find the \$1 Target maps I bought this summer. WHEN I find them, I will put one of those on the table!