Weight vs. Mass

30 The conceptual students are finding the relationship between weight and mass. This is two classes’ worth of data, so 12 groups, each with 6 objects to measure mass using a triple-beam balance and weight using spring scales. I made this graph, but my students had to graph by hand and did not have to determine uncertainties in the slope or y-intercept. I did that for my own pleasure.

Today was a strange day because we administered PSAT/NMSQT tests to all the 10th and 11th graders, then we had periods 4-8. Tomorrow we have a half-day followed by inservice, and will meet for periods 1-4. During 4th period, I have hall duty. I don’t mind having hall duty twice for each of my other classes meeting once, since this means I don’t have one class getting absurdly ahead of the others. However, due to this wacky schedule, I am not assessing my conceptual classes this week.

##BFPM  ##graphing




25 One thing I have noticed is that the Modeling Instruction materials for physics do not have a lot of practice materials in them. Practice is what helps you get better at things (it builds myelin layers around the circuits in your brain), so over the years I have made various practice materials for my students.  Today we were getting ready for tomorrow’s assessment of x vs. t and v vs. t graphs with my conceptual classes. So last night I made some practice problems. I drew them by hand on graph paper with a sharpie pen and a ruler, which was much more relaxing for me than trying to create them all on the computer. Doing it on the computer is easy enough with OmniGraphSketcher and Excel, but drawing these out by hand is very soothing for my brain. Soldering is like that too. I am perfectly happy to sit and solder for hours at a time.

Anyway, we did not get to go over the answers in class, so I made a colorful answer sheet, scanned it, and put it on Moodle. I hope the different colors help the students get which parts are which. The photo above shows two of the six “problems” I gave the kids.

Also, it was “Disney/Pixar” day at school for spirit week:

(Army guy, Buzz Lightyear, shiny Superman (?), Dalmation, Elastigirl, kid from Up, ?, Cheshire cat, “Kitty” and in front is Hercules)


##CVPM  ##graphing




22 My first period class made my day on Friday. While a few students worked silently by themselves, the rest divided into two groups to look at a set of graphs and answer questions. The graphs were originally given as x vs. t graphs and earlier this week the kids drew the corresponding v vs. t graphs. We were looking at the graphs again and these were the questions:

  • What is the total distance?
  • What is the total displacement?
  • What is the average speed?
  • What is the average velocity?

The two groups were awesome. They had good discussions. They asked each other questions. They explained things to each other. The video clip above isn’t the best discussion I heard, it’s just the one I got to with the video camera and which then had the best sound quality. Another group had even better discussion, with better participation among the group. Unfortunately, I could not make out what they were saying once I looked at the video.

I’m sorry this post is two days late. I think that may wind up being par for the course if I wind up with more videos. Deal with it! 😉


##CVPM  ##graphing  ##studentdialogue



19 Today we started making the big connections (actually we did this yesterday with one class) between position vs. time graphs and velocity vs. time graphs. We got predictions for velocity vs. time graphs first, sharing them on the board at the front of the room, and then we used the motion detector to see  which (if any) of the predictions were right. Then with this one, which was the last one, I used the tools in Logger Pro to get points on my position vs. time graph and students calculated the slopes. Then I used Logger Pro to get the average velocities from the velocity graph, and the values were pretty similar to the slopes. Being able to do this and annotate it without having to walk back and forth between the board and the computer is one actual good use of the Promethean ActivBoard in my classroom. Finally, we applied the slope = velocity to draw a variety of velocity vs time graphs for a variety of position vs. time graphs. Sometimes practice is a very good thing! Tomorrow it will be “Mistake Game” time with the velocity graphs and then we can move on to using graphs to answer questions!


##CVPM  ##graphing  ##velocitygraphs


9 My conceptual students are a mix of “getting it” and “not getting it” right now. So we did a quick review to get the pattern of variables, numbers, and units, fitting in with the overall pattern of axis labels and titles on graphs. For homework this weekend, they are doing Dan Meyer’s flight data activity and trying to get meaning out of slopes and y-intercepts. I’m grading their circle lab Lab Reports for my homework.


7 This graph originally had some errors. It is based on a linear data set that was one of several I assigned for graphing-by-hand practice. Students spotted the mistakes and we fixed them. Then as students practiced making graphs in Excel, we referred to this diagram to help customize the trendline equation from Excel. Conceptual students have their first graphing assessment tomorrow.

(I know I didn’t post yesterday. Oops.)

More Graphing


5 My conceptual classes are learning how to determine the slope of a best-fit line and then write an equation with appropriate variables. We’ll be adding units and graph titles tomorrow. I have some linear data that I give them to practice with. This data is prefaced with a little story about an FBI agent measuring her banana tree every month. It grows pretty fast!

My AP classes are learning to use Excel to calculate uncertainties in measurements and then use the uncertainties for error bars on the graph. They also have to use the LINEST function to determine uncertainty in the slope and y-intercept. This student has just learned something that doesn’t work, a very valuable lesson!



4 We are starting graphing. Some students are doing great at this and some are not. This is a pretty darn good graph so far. Next week we will be adding a title, best fit line, and an equation. In addition to the graph of data from the circle measurement activity, my students are graphing four other data sets this weekend as practice.

The student who made this graph was pleased that I chose it for my photo for today! (I’m sorry it is hard to read. My phone camera doesn’t do that well up close, I guess.)