Day 113:

Thursday, 18 February 2016

So I asked the kids to set these up in the lab:


Purple text beneath drawings are in the kids’ words.

Then I put this up as a challenge question:


A few groups realized right away that the system’s already in equilibrium. Some needed to play with masses for a while to realize it.

Day 112: Force Table Lab

Wednesday, 17 February 2016


Set the kids up today in lab with the following question: given two forces of 0.6N each that are set up with a 90° angle between them, what force could you add to pull the system back into equilibrium? The kids have no experience with forces in two dimensions.

Most guessed 1.2N set up in the opposite direction of the angle bisector (“because the two original forces are equal”). So I sent them to the force tables to test. They were almost universally surprised to learn that 0.85N was the required balancing force.

Why? The best answers were some variation on “the original two 0.6N forces are pulling against each other somewhat.”

Lab setup: 5 force tables with 4 slotted mass sets each. Lab groups of 2-4 kids.

Here’s my lab: 2D Forces

Day 111: HowStuffWorks Visit

Tuesday, 16 February 2016


So I help coach this robotics team (FRC #2415 The WiredCats!) and today we got to pick the brains of their podcasting crew for advice on our own podcast. The trip included a tour of their new-ish offices at Ponce City Market, a huge redevelopment near midtown Atlanta. Above is me clowning in the studio where Stuff You Should Know is recorded.

My favorite bit of advice is that you should absolutely reach out for interviews because people are more approachable than you think. We also talked about how important a listener mail segment is to including your audience in your show. And the kids had a chance to ask great questions like “how do you balance entertaining and informative?”

Tech advice included:

  • invest in the best mic you can (Snowball and Yeti USB mics are great) for everyone who will be speaking
  • hang blankets or foam to knock down echos your studio
  • monitor while you record so you can adjust audio levels on the fly
  • say “beep” whenever you make a mistake — the blip on the audio track will be esay for the person editing to pick up on and edit out
  • put your interviewee at ease by telling them up front you’ll be editing
  • don’t be afraid ask your interviewee to restate their point if you think they could say it more succinctly — they’ll appreciate being asked
  • craft your interview questions so that you can edit yourself asking them out


Days 102-110: Discovery Takeover

Tuesday, 2 Feb through Friday, 12 Feb 2016


Learning patient assessment in Wilderness First Aid class.

Tuesday, 2 Feb: I’m teaching a Discovery course last week and this. Discovery is a leadership and outdoor education program for all freshmen at my school. Students do two weeks of class on campus (4-6pm daily) and a weekend expedition. This course’s theme is Wilderness First Aid and includes instruction with the option of certification at the end. Above, two student leaders practice patience assessment on campus today.


The entire group runs through the Turnstile.

Thursday, 4 Feb: At Discovery today, we played one of my favorite games, Turnstile. In the game, the team has to build up to running through a jump rope all at the same time without touching.


Pretty much perfect force vs time graph for about 3 kg of mass.

Wednesday, 10 Feb: We developed graphs of force versus time using a force probe. My advice to the kids was push as lightly as possible until you get the block to break free from friction.


A tiny plasma cutter

Thursday, 11 Feb: At the Atlanta Metro Physics Teachers meeting, two different teachers brought these tiny plasma cutters to demo. We also heard from guest speaker Dr. Patrick Enderle from Georgia State on Argumentation in Science Classrooms. He co-developed a learning framework called Argument Driven Inquiry.


Introducing friction problem-solving.

Friday, 12 Feb: Today I made up a few friction-y problems (above and below). Previously this week, we finished our lab (above) where the kids had to figure out the relationship between an applied force just moving the block and the weight of a block.



My stickers arrived! Stickermule rocks — turnaround within a work week!

Day 101: Fnet=ma

Monday, 1 February 2016

These are the scariest fan carts I’ve ever seen — what with the exposed blades and extremely high speeds. Here are a few sample runs where the cart is steadily loaded down with more mass. Oh, and I realize that the force of friction increases as the weight of the carts increases. I didn’t want that but didn’t have a better solution. Here’s what the relationship between the mass and acceleration looked like for me:

Screen Shot 2016-02-01 at 8.57.08 PM

Kids were surprised at the leveling off of the graph. Great time to talk about human error! Oh and we also decided that rounding to three decimal places on such small numbers probably wasn’t a wise idea.

First time my kids have used motion detectors in my class. We also learned 3 Excel tips today: 1) you probably want the Scatter Plot chart type in physics, 2) applying the sorting filter thing to re-sort columns of data, and 3) the zoom option is probably more useful than changing the font size in a spreadsheet.