# Day 40: Mass & Craters

AP Physics: Mass

Students worked on a lab practical to find the mass of an unknown object using a modified Atwood’s machine. My plan is to use spring scales to verify the mass the determined, then use this to introduce the difference between inertial mass and gravitational mass, but time got tight and most groups need a little longer to finish their calculations.

Earth Science: Craters

During yesterday’s lab, it quickly became clear that my students did not have much sense of how craters are formed. Today, I got out some trays of sand and an assortment of marbles and we explored how mass and impact speed affect the crater size. I was really excited when the groups who finished early started asking new questions, like how the depth of the sand or angle of impact changes the crater, and coming up with experiments to answer those questions. This is why I love freshmen! We also dropped a shot put into a bigger tray of sand and got some slow-motion video just because its cool.

# Day 39: Assumptions & Moon Landscapes

AP Physics: Assumptions
Some of my students are losing track of the tools they have for problems involving forces, so we started by whiteboarding as many different representations for a simple force problem as we could and then making a list of what we have in our forces toolkit. From there, students worked on some TIPERs problems. I had students answer each problem using a CER, but turned it into a CAER by asking them to state and justify key assumptions before diving into the evidence. We had some good conversation about what makes something an assumption rather than evidence or a claim. We will definitely need to revisit this as the year goes on, but I liked hearing my students start by articulating what they had to just agree is true before digging into the rest of the problem.

Earth Science: Moon Landscapes

Students looked at a topographic map of an area of the Moon. They made some good observations and inferences about the craters formed, but students have had limited exposure to topographic maps so far and, as a result, had trouble connecting the map to what the would physically see. Next time, I think I’ll start by having them look at an actual image of the Moon, then transition to a topographic map of the same area.

# Day 35: TIPERs & Moon Phases

I’m at the NSTA Regional Conference, so students have a sub today.

AP Physics: TIPERs

Students worked through some problems applying Newton’s 2nd Law, mostly out of TIPERs with a few calculations thrown in. I love listening in on the conversations students have on their way to answering TIPERs problems, so I kind of hate leaving it for a sub, but I’m looking forward to seeing their work when I get back.

Earth Science: Moon Phases

Students took their assessment on climate change, then did a follow-up to Tuesday’s lab modeling phases of the moon. Today, they used a moon phase calendar to determine which way the moon revolves around Earth.

# Day 33: Friction & Moon Phases

AP Physics: Friction

Students did a lab to determine which variables impact the magnitude of the force of friction. This lab provided some nice opportunities to talk about uncertainty and how big a difference is big enough to matter. Talking about the uncertainty also lead nicely into the fact that the model of friction on our equation sheet is actually pretty limited.

Earth Science: Moon Phases

Students worked through a simple lab using a lamp, softball, and golf ball to model the Moon’s revolution around Earth and predict what phase of the moon would be visible at various positions. Students were very successful at connecting how much of the lit portion of the golf ball was towards the softball to what phase of the Moon would be visible from Earth.