With both levels (Advanced and General) I opened up an inertia balance graph I had created in Logger Pro. I used to demonstrate a few of the other awesome features of Logger Pro. The first was the Interpolation feature (under the Analyze menu). Earlier in the week we did the Inertia Balance challenge where the students used their hand graphs to predict an unknown mass (a king-size candy bar). The students immediately saw how much easier and more accurate this method was compared to the hand graph. Another feature I showed them was a calculated column. My original graph had 3 columns; mass added, total time, and period. The period was the calculated column. I showed the classes this as a preview to working with nonlinear graphs, setting the table for the process of linearization. This lead us into a pre-lab discussion for an experiment that will give us a non-linear graph.
The Advanced classes are investigating the factors affecting the period of a pendulum. It was interesting to see the discussion among the class and lab groups about whether or not the amplitude affects the period. I really did not do much other that suggest there is a really easy and quick way to see if it really matters… most groups decided to do a quick check with the equipment. I did encourage the groups to stay away from really big amplitudes.
The General classes are investigating a mass on a spring. They are just looking at period as a function of mass. The spring itself as a factor that affects the period did come up in the pre-lab discussion. We agreed to see if it is a factor by comparing the slope of the linear graph when we WB it. I like this as the second experiment for the general classes because it essentially the same experiment as the inertia balance (period vs. mass), so there is no new procedure for the students to write, they are able to see that the data table is the same, gathering the data is essentially the same, BUT they will end up with a non-linear graph to work with.
In both classes (Advanced and General), we spent the first part of class completing two independent peer reviews of student lab journals. Each student read through two other journals, completing a feed back rubric as he/she went. I have found that this helps the overall quality of the journals, especially for the students that have never kept a lab journal.
The rest of class was spent feeling the ‘Logger Pro love’. The classes worked through a Logger Pro tutorial on basic graphing that I made by modifying one that comes Logger Pro. It has the students follow a set of steps to set up the columns, enter data, put o the linear fit… the data plotted was what each student gathered in the Inertia Balance experiment. It was a nice opportunity to talk about our ability to draw the best fit line… comparing our calculated slope with what Logger Pro gives us. The Logger Pro love comes from me telling my classes “I love the Logger Pro’. One year a class even made a class T-shirt with I (heart) Logger Pro on the front.
After the whiteboarding of the ‘wiggler’ experiment, today we used our graph and/or EOL to predict an unknown mass. Up to this point I have been calling it a physics wiggler. Today I told the students it is really known as an Inertia Balance. The focus was on the ‘balance’ ad we know balances are used to measure mass. This was the hook into the challenge..use the inertia balance to measure an unknown mass. As an added incentive, if the predicted mass of the unknown was within 5% of the actual, they could eat the unknown… a king size candy bar! (Cue Bow Wow Wow)
As I expected, not many groups earned the candy. It provided a really nice chance to talk about being careful when gathering data.
Today was a bit more of me than I really like. All the classes needed to whiteboard the results of the Physics Wiggler (aka Inertia Balance) experiment. Before the actual WB’ing, (whiteboarding) be reviewed how to calculate the slope of a linear graph and how to write the EOL (Equation of the line). After that, the students prepared their whiteboards. The Advanced class made two; Period vs. Amplitude and Period vs. mass added. The general class only worked on the period vs mass added.
We had a board meeting, but not in circle set up. The room I teach in is not very conducive for circle white-boarding. I need to get in the habit of snapping some pics to include here. Here are a few screen shots of the summary:
One my points of emphasis over the last few years has been to conceptualize the graphs…. explain what the graph tells us in the very simplest sense. I usually try to quote the student(s) that provide the explanation.
As mentioned in the last post, today was mostly gathering data. It is always interesting watch the different techniques for determining the period. Some students are convinced they can accurately time one cycle.
SIDEBAR: We have two different version of the inertia balance. We have some smaller commercial ones (they are pretty old, so I’m not sure where they were ordered from) and some larger homemade ones. I add some mass (taped to the bottom) to some of each type to vary the fundamental so all the groups do not get roughly the same slope value.
We started the class by taking the safety quiz. It is a 10 question multiple choice quiz. I always use our Senteo Student Response system so the students can learn how to use them (although most students are now familiar with them because more of our teachers have started to use them.)
Following the safety quiz, we started out first lab. I use the modeling method, so the experiment started with a demonstration and making some observations.
SIDEBAR: Our first unit is called Essential Skills. It is everything we want the students to know how to do. It also allows us to let the students experience modeling style physics experiments… ones with no handouts. This unit includes reviewing how to write the EOL (equation of the line) for linear graphs, using Logger Pro to create graphs, linearizing non-linear graphs. Or first experiment is one that will give a linear data set.
The first experiment uses an inertia balance, but I do not call it that right away. At this point it is known as a Physics Wiggler… it wiggles back and forth. This name leads to a definition of period (and frequency). We notice that we can change the period by adding mass to the wiggler. This leads to a discussion and decision about independent and dependent variables. Usually the class ends up with two experiments: Period vs. Amplitude (with constant mass) and Period vs. Mass Added. After just a few different amplitudes, the students see there is no effect on the period, so they don’t worry about amplitude with the mass added data set. We write the purpose, make our hypotheses, but really don’t talk too much about the procedure. I emphasis that we want to be as accurate as possible and to think about how we can make this happen as we gather data.
With the General classes, we guide them a bit more… we demonstrate how do gather data for the period (time ten cycles, the divide by ten) by looking at the amplitude relationship. This makes the data gathering a bit shorter for them.
Monday will be all data gathering.
There were three items that were on the docket for today. The first was to discuss WHY we completed the Marshmallow Challenge. I choose four ‘reasons’ that related to our class. The first (and the one most students sense) is the engineering connection. The not so obvious ones are:
1. communication — essential with your team and comes in many forms. In class our team is our class or lab group and even the teacher – student team.
2. Teamwork — more success with a team. I tied it to a study group working on a set of problems or preparing for an assessment.
3. Failure — We talked about how it is necessary and that we grow from failure. We learn what does not work, and move toward finding something that does work.
4. The process — We discussed the process, build, test, modify, test. In class we use a similar cycle, build a model, test it, modify it if needed… Too bad that this part is not easy to connect to the modeling cycle at this point. I’ll have to remember to bring it up again at a later time.
Task 2 was to talk about lab safety in preparation for our safety quiz — to be honest, not my favorite topic. I understand the importance, but still not my favorite.
Task 3 was to set up our lab journal in preparation for the semester and our first experiment. This involved discussing and explaining the format. With the Advanced class, I run two lab journals so I can be grading one and the students can work in the other. We title them Alpha and Beta.
Today was a normal schedule, so we had 53 minute classes. I started both classes (Advanced and General) by explaining why we levitated the malted milk balls.
SIDEBAR: I have a sound educational reason (or reasons) for everything we do in class. I explain my students that I will do my very best to never waste their time… what we are doing always has a reason that might not be clear right away, but will become clear at some point.
Back to levitating malted milk balls: Most of the students saw this simple activity as a way to demonstrate some pretty cool physics, namely the Bernoulli effect. But, behind the scenes there was a second reason. It provided an opportunity to talk about Carol Dweck’s work on mindset. I found this graphic:
from this website:
The example I used for a fixed mindset related tot eh activity was thinking, “I can’t do that” or “There’s no way I could ever do that so I’m not going to try” For a growth mindset, it was, “Well, I’m not sure how to do that, but I’m going to try this…” or noticing another student trying something, “Oh, I can do that…”. I think the connection to studying physics was pretty clear.
We also spent a few minutes talking a bit more in detail about the course using our syllabus.
We spent the last half of the class period doing the Marshmallow Challenge. This is a nice first day activity that I learned about from reading Frank Noschese blog, here.
Well, I’ve jumped onto the 180 bandwagon. I’m a bit late starting, but starting nonetheless. The first day is always a split day with the freshmen in for the morning, then the rest of the student body joining in the afternoon. This means we see our classes for only 20 minutes. What can you do in 20 minutes, well, here is what I did:
1. Took attendance using a seating chart, but not really the typical seating chart. I learned this technique from one of my mentors, an incredible woman named Patricia Westphal. For each of my classes, I export student demographic data from Infinite Campus into an Excell spreadsheet. Then I can sort the data according to any of the demographics. I explain to the students that physics is about gathering data and solving challenges and this is the first one. Once they correctly figure out the pattern, present the data gathered in some type of diagram with an explanation, they can choose their own seats. it’s worked on when there are a few spare minutes, but I never give them in-class time to work on it.
2. Showed them the syllabus, my electronic version. Here is the link to the Advanced Physics e-syllabus
and this is the General Physics link:
The students were also given a paper copy to read more thoroughly.
3. With the remaining few minutes we levitated Whoppers Malted Milk Balls, described in the Little Gems Column of the September 2005 issue of The Physics Teacher. I switched from the peanut M&M’s used in the column to Whoopers because of possible nut allergies and because they have less mass so the students find it easier to leviate. This year a colleague added a small piece of a straw to make it even easier.