Killing It…

I’m sitting here on Halloween day grading Thursday’s test, and feeling a need to congratulate a few people. So, congratulations to the students who are KILLING IT on this test, first of all (and there are quite a few). And secondly, congratulations to me…

Anyone who has corresponded with me about last year knows that it was a total mess. I was continually frustrated by students unwillingness to practice and learn the most basic procedures, let alone do real thinking and scientific heavy lifting. This caused me to drastically lower my expectations for the course, making even the students who found the ideas challenging and exciting bored out of their skulls. (Note the Halloween-themed language here!)

This year ain’t a cakewalk, but it IS fundamentally different. Not only are kids practicing the procedures that make up our extensive “balance force model” toolkit, I see them using these procedures in creative analytical ways. On this test, for example, you see a student choosing a different positive direction for two different situations, to make his own analysis more straightforward, and carefully choosing the lengths of his force diagram arrows to match the magnitude of the forces.

This kind of work was unheard of last year… Now I’m seeing it over and over again. Again, not a cakewalk BUT still amazingly satisfying.

Happy Halloween!!

##bfpm ##physicsfirst ##struggle


Noodle Bridge Breaking

Doing a lab on Monday about calculating the maximum FNoodlesOnObject, and I figured I’d make a slowmo example of the procedure. The sound is beautiful!!

##physicsfirst ##bfpm

Being Active and Sum of Forces

I’ve been trying lately to look for any excuse I can find to get students out of their seats, even for a few minutes. Students need practice with the basic skills that show up on assessments, but if we’re just doing that practice all the time things get monotonous and students get restless.

Today I wanted to practice using a “sum of forces equation” to solve for an unknown force with an example about struggling to lift a file cabinet. To get into this, we spent 15 minutes reviewing sum of forces with the PhET Forces Basic simulation (, then I asked student to stand up. One student in each pair sat on a table, and the other student tried to lift the table. Not easy to do!!

Then we turned back to the example at hand (our silent “Check-In” to start the class), shown below.

For whatever reason students have a hard time figuring out that the person is pulling up on the cabinet even when the cabinet doesn’t budge. Many leave the force exerted by the person off the force diagram completely, because they don’t see the “lifting” actually happen.

Then we put a real filing cabinet on a force plate, and try to lift it. This student pulled up a bit, said “This is mad heavy!!” And gave up a bit, then took another shot and lifted it up all the way off the scale. This graph couldn’t be a more beautiful illustration of this!!

##physicsfirst ##bfpm


Things have been going far, far better than last year, but that doesn’t mean that they can’t go better still… We’re trying to move kids from a mindset where the teacher is the only person in charge of keeping order in the class (including giving “demerits” for unwanted behavior) to a system where kids feel accountable to each other, and ultimately to their own future.

These forms are one step toward this, I hope. We used them for the first time today. I showed students the form and asked for volunteers who would simply watch what was going on. No judgements, just honest feedback.

I haven’t totally thought through what to do with these. I just posted them one by one at the end of class, in silence, and asked students to reflect. I’ll keep them every day, and look for patterns after we’ve collected data for a while.

I would LOVE to hear others’ thoughts on next steps, or how to revise the project!


Materials Bags and Lab Roles

Today we did an experiment to determine the relationship between mass and the force exerted by the Earth on an object that has mass. An experiment worth doing, to be sure, but I’ll bet most people who read this post have done this lab themselves… So instead I’ll discuss something that I’ve realized is essential to a successful lab activity with my kids.

First, I put all the materials in a bag. When students begin the class they know not to touch the stuff until we actually begin, but that’s virtually impossible for them to adhere to unless that stuff is sealed away. The plastic bag barrier makes all the difference in the world. Opening the bag is effectively off-limits, whereas futzing with a spring scale just isn’t really.

Second, I go out of my way to define explicit lab roles. This can be something very straightforward, but it’s important to give everyone a chance to feel like they have something essential to do. The “Mass Manager” may have had just ONE big moment to shine in the time allotted for the lab, but they stay on their toes getting ready for that moment.

At the end of the activity you can see my “CHAMP” expectations posted. C for conversation level, H for how to get help, A for a description of the activity, M for movement expectations, and P for what I’ll see you doing if you’re participating. Just making these things explicit makes it MUCH easier for kids who want to do right by the class to be productive. And don’t all kids basically want to do right by the class?

##physicsfirst ##bfpm ##motivation ##explicit

Force Diagram Card Forms

Many of my students last year struggled to understand what congruency marks were all about, so this year I introduced them more explicitly with an extra step in each problem. First, circle “constant motion” or “changing motion”, then circle “balanced force” or “unbalanced force”. This connection is helpful for certain, and everyone gets it. Eugenia Etkina would call this “procedural scaffolding.”

Next, to introduce the marks themselves, I was looking for something other than just plain old white boarding. I made six cards with force diagram templates (two shown here in orange here), and student had to label the names of forces and decide which applied to which situation.

They enjoyed this more than just making a single whiteboard and discussing for a while, and it made for good discussions. One diagram showed two equal forces balancing out one longer force, and a lot of students applied to a boy and girl holding up a box. Hurray for gender equality!!

After labeling, students sent a “runner” up to a board designated for each problem, and taped their card up. This gave us a chance to really talk about the different choices. This one was pretty easy, everyone agreed, but next year I may make it fit a slightly trickier situation.

##motivation ##physicsfirst