# Day 22

Pretty quiet day on the classroom front.

Physical Science: We had a very successful quiz yesterday, which I talked about in yesterday’s post. Well today we started the last part of the Science Skills unit: Graphing and analysis. To get things going we collected data where we will analyze the students height versus their wingspan (finger tip to finger tip with arms stretched out to the side.

The hand out is here.

They just collected the data, and after we talk about graphing and such tomorrow, they will make the graphs.

Chemistry: We are at the end of our Physical Properties of Matter unit, so students got the unit review, which we will go over tomorrow.

Physics of Light: We started collecting data for our bendy light lab. We had 5 groups, 2 with water, one with glycerin, one with corn syrup, and another with agar.

This is the setup: an old CD-ROM disc with a paper protractor glued to the top of it (same size as the CD) is the base. Then a semi-circle dish sits on top with the fluid of choice. With the right fluid, you can easily see the beam coming through on the other side. With the base, the angle measurements are easy to get.

The kids got the data really quick, which gave them time to get a graph going. All groups made comment that it looked like a side opening parabola.

So the kids try to graph it as a y^2 v. x graph, and that ends up looking crazy. So I ask if they know of any other graphs that have a shape like this. Eventually we get to a sine wave function. So we plot one axis, say y, as sin y v. x, but it looks the same once its done. So then we do the sine function on the x axis too, and you get this:

Exactly what it all means, is yet to be determined.

Plot.ly: the above graphs were made with Plot.ly, a free online graphing program. It is meant to be a possible replacement for LoggerPro, since Vernier does not seem interested in making a Chrome compatible graphing suite. So I gave this a try after hearing from Ryan Peterson (@brillionnerd) of Brillion HS, that it is worth a look. So I gave it a look, and it could prove useful. I was a little frustrated at first, trying to figure out how to do functions and such, and also deal with the fact that you can’t switch from radians to degrees. But, it has possibilities.

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## 2 thoughts on “Day 22”

1. You and Petetson are traitors!

Just kidding. Are you using a beam splitter with the lasers? Is the green easier to see with? Agar huh, I’ve been using plain Knox gelatin .

• I’ve used a beam splitter before, but didn’t think to do this yesterday. The kids were able to get there readings and graphs seemed good. As for the Agar, our bio teacher had some she just had to warm and pour, so way easier than making gelatin.

The green lasers are way better for optics than the red ones. They are so bright and easy to see, even in a room that is not real dark. I found some good ones for cheap on Amazon a couple years back.