# Day 16

Physical Science: Today we did the data collection for the Precision of Measurement activity.

As you can see, students cut out the paper “meter sticks” that I posted a link to in Day 15. The sets of rulers are the same for everyone, and have the same magnitude of graduations on them. this fixes the issues from the Measuring the Measuring Tool Activity from last week.

Now that everyone has the same standard of measurement, we got much better results overall.

As you can see, the results agree much more between groups, and even classes (2 classes presented here.) There is still some big differences between the measurements of the desk and legs of the desk. We talked about how since they had to move the ruler so much to get those measurements, that we introduce more error into those measures. We then talked about a homework question that everyone had gotten correct: you should always pick a measuring device that is appropriate to measure with, larger scales for larger values, and smaller scales for smaller stuff.

My principal stopped in to see what we were up to. The activity got two thumbs up from her, so there you go.

Chemistry: We white boarded results from our Mass and Volume lab. Here you can see the results:

So everyone came up with a pretty good explanation for the slope, but y-intercepts were an issue. We spent time talking about this afterwards, and decided that if you have no volume (no matter occupying space) then you should have no mass. With that in mind we talked about why we each got different slopes too.

Well since we all used the same procedure, the same measurements, the same analysis, then the difference must be due to the metal bars we measured. Since mass and volume are physical properties, then it stood to reason that this may also be a physical property. One group had on their board that the slope was the ratio of the bars mass to it’s volume. This is apparently different for different substances.

With that in mind, we finally defined this ratio as density. Our line equation can then be simmered down to: Mass = Density*Volume

A nice little model.

Since I use a SBG model in Chemistry and Physics, that means I have to offer some reassessments. Well I invented a new one this year, and I had my first 3 takers.

I call it the “Call Your Shot,” reassessment. Students can pick a learning objective, and once a week tell me that they are going to “call their shot” during our study hall time, and then come in and get a one-and-done question to show mastery of that objective.

It’s a home run or strike out. Mastery or nothing.

I kind of stole the idea form this guy:

The Babe called his shot once too!

So that was fun to try out. Oh, and all three hit a home run.

Physics of Light: Today was more about learning to analyze data. I have three kids who took Physics with me last year, and I made them team leaders. It was their job to help kids figure out why and how we were linearizing graphs for our Light Intensity Lab.

Not going to lie, we got some mixed results. We’ll have to go through the discussion tomorrow and see if they can get a model for light intensity and distance.

I have pictures of them in lab, but I can’t find the camera I used. I’ll try to upload them later.

Bonus:

Another great video from Smarter Every Day.