Today I was at a workshop as part of the College in the Schools class I teach, and part was a talk on the history of the search for the Higgs.
The first three pictures below depict the basic idea of how the Higgs gives things mass. In the model, space is filled with the Higgs field (remember aether?).
Now the analogy explains how we might see evidence of the Higgs field even without something for it to glom onto. This requires an energy input.
Always great to learn!
I learned about lensmob a couple weeks ago from Frank and I am really excited to use it. Once an album is set up, anyone with the email address can send a picture to it. I plan to start by having students in each class (each has its own album) send pics of their whiteboards both for later reference as well as in case we don’t get to all of them in a particular day. I hope to expand the use later as well.
Lots to write about here, but I’m going to try to keep it short by promising to write later about the cart launch lab. I was inspired by my colleague Ben who put together an amazing packet for the regular physics classes at our school. I was planning, for my college level class, to jump right into problem solving in constant velocity. After looking at what Ben had done and cross referencing with Kelly, I decided I needed more conceptual materials before problem solving. Thus I put together a packet that draws largely from Kelly and the standard modeling materials. The main difference, however, is that class I teach, since it is articulated through the University of Minnesota, emphasizes algebraic problem solving more so than modeling instruction. Thus I wrote a new worksheet, practice 3 in the packet, to deploy the model. It emphasizes solving the problem algebraically but using graphical methods to guide and check the answer. Let me know what you think, here’s a view only copy of the packet.
Today my colleague and I were looking into ways to rearrange our room to better support both whiteboarding and labs, and one of the stumbling blocks was leaving enough room in front of our demonstration table for students to present whiteboards. Then we discovered that we already had hangers on the whiteboard behind the demo table that held the whiteboards just fine; hello extra space!
Today my colleague Ben and I sought to revisit why and how we do lab reports. We started by identifying what we want students to be able to do (Goal), then listed the specific skills they need to be able to do so, then (moving to the pictures below), wrote down the steps we think we need to teach to students to get there, and finally outlined how that would look when a lab is being completed.
Last week in our weekly Physics teachers meeting we briefly talked about the possible labs to build the Unbalanced Force Particle Model (UBFPM, AKA Newton’s 2nd law). The modeling materials use a modified Atwood machine, and I planned on doing a further modification to mount a force detector on top of the cart to directly measure the force (that way you somewhat circumnavigate the problem where you must keep the mass of the system constant, thus should transfer masses from the hanging mass to to cart and vice versa). Kelly simply stated that seemed too complicated. So I decided that on my planning day today I would test to see what worked better. I modified Kelly’s version slightly, since I don’t have cool brass knuckles. I simply varied the displacement of the spring with each trial, thus varying the force (students would have to start by first measuring the spring constant of the spring, more on that below). The results are above; it worked surprisingly well. Additionally, the inverse of the slope of the graph should be the mass of the system, and it easily matched the system mass within uncertainty. Pretty cool. The acc vs mass of cart version worked similarly well. The Atwood’s data turned out good too, though.
Both methods took me about 20-25 minutes. Both had minor setup problems, but nothing serious. I did, however, find a problem with my modified Atwood version with constant force (constant hanging mass); as the acceleration changes, so does the tension in the rope (analysis of the hanging mass yields that T=mg-ma, so as acceleration increases, Tension decreases). Should have been obvious to me, but wasn’t before trying it. It’s still within 10% for the range of my values, but I wouldn’t be happy waving my hand at it.
The result is that I will be using my modification of Kelly’s version where kids will vary the spring stretch to vary the force on the cart (which I think is more intuitive anyway), then vary the cart mass with constant stretch to get the a vs m data. I had been debating putting spring force in this unit anyway (instead of the Energy unit), this just gave me a really good reason to do so.
Yesterday was a staff development day. Our principal wanted us to remember what it is like to be a kid, so for the afternoon we all got a schedule. It was a bit humbling to go to four different ‘classes’ and try to remember everything, definitely a good experience.