Today, AP Physics 2 students explored all three types of heat transfer. With unpainted and black-painted cans of hot or room-temperature water, heat lamps, and fans; students explored heat transfer via conduction, convection, and radiation. This is one of my favorite labs, and I was gone to work on the alignment of our science curriculum with the Next-Generation Science Standards. I left them with an awesome sub and a cart full of goodies.
##thermo ##paradigmlab
I’m going to be out of the classroom tomorrow to work on the alignment of our science curriculum with the Next-Generation Science Standards. So, today, I demonstrated to students how to connect to the LabQuest 2 from their Chromebooks, export the graph, and export the data. I expected that we would have done this already this year, but so far we only had to manually record data from the LabQuest 2. In tomorrow’s lab, they won’t want to manually copy 60+ data points. I used my new HDMI-to-VGA connector to display the Chromebook screen and the Elmo to display the LabQuest2 screen.
##thermo ##tech ##labquest2 ##chromebook
Today in AP Physics 2, we whiteboarded (okay to making that a verb?) three problems. Two groups whiteboarded each problem and we compared and contrasted the two solutions. For one problem where students were calculating the increase in pressure in a tire due to an increase in temperature, both groups presented similar solutions and the same final answer. Fortunately, one student spoke up and questioned the final answer of both groups. He pointed out that both groups failed to based their calculations on the absolute pressure in the tire and instead used the gauge pressure. It was great to watch him explain the error and his solution to the entire class as he spun around in his chair so he could address everyone. I captured a couple of pictures mid-spin, but he noticed me!
##thermo ##whitedboarding
I inherited these kinetic theory activities from the physics teacher who retired when I started. I’ve always used them as they require students to look at everyday occurrences from a very different perspective (through the lens of kinetic theory). I think these activities are even more important this year with AP Physics 2 as I infer that the new course emphasizes students mapping reasoning between macroscopic and atomic scales (“connect and relate knowledge across various scales…). As a result, I really emphasized the translation between macroscopic observations, measurements, and properties; and the corresponding atomic properties. Students surprisingly struggled with this shift of scale. For example, students struggled to reconcile that from a macroscopic perspective, a bouncing rubber ball’s kinetic energy is decreases and is transferred to thermal energy and from an atomic perspective the kinetic energy of the atoms in the ball increases. Initially the student started his explanation by stating that the kinetic energy of the atoms in the ball decrease. I occasionally directed the discussion back to considering the computational model of an ideal gas that we have been exploring which appeared to help students span the macroscopic and atomic worlds.
One of the activities is to cup your hands around an inverted flask and observe what occurs (bubbles leave the lower beaker):
[Update: 30sep2014] Here is the activity handout.
##thermo ##labs
Today in AP Physics 2, we continued to explore the computational model for the atomic model of an ideal gas by varying the properties of the model (e.g., make the atoms heavier, increase the temperature, decrease the temperature). I also introduced the First Law of Thermodynamics by reviewing the Energy Transfer Model (ETM) from last year.
Outside of class, I started to score some labs. I had students write their labs in Google Docs and submit them to Canvas via the Google Drive integration. As a result, this is what I see in SpeedGrader:
While I can provide comments and make annotations in SpeedGrader via the Crocodoc integration, this isn’t the level of integration with GoogleDocs that I wanted. I want to make comments within SpeedGrader but have those comments reflected in the original Google Doc. I don’t want students to have to go to Canvas to see my feedback on their lab. I want that feedback (suggestions) to be visible whenever they view their lab whether immediately after I score it or weeks later while they are writing a new lab report. To see if this was possible, I asked a student to resubmit his lab by submitting a link to the Google Doc via Canvas (students have already shared a “labs” folder with me in Google Drive and all labs reside in this folder). As a result, this is what I see in SpeedGrader:
Perfect!
##setbacks ##chromebooks ##canvasK12 ##tech
Yesterday, I presented the atomic model of an ideal gas, which students are familiar with from chemistry, from a physics perspective. I didn’t have a paradigm lab to introduce this model. Instead, I shared a GlowScript computational model ported from the VPython hard-sphere model of a gas. We didn’t have time to explore the model today, but will on Monday.
This evening, I read about a much better way to start this unit from Scott Thomas. He had his students develop and explore this computation model over an extended period of times and find the relationship between average kinetic energy and temperature. Next year will be better!
##thermo ##paradigmlab ##computationalmodeling ##setbacks
Today in AP Physics 2, we tied up some loose ends related to fluids before starting thermodynamics. When students performed the lab practicum a couple of days ago, almost all of them placed the cup too far away despite accurate measurements and an accurate computational model. I took this opportunity for us as a class to discuss what sources of error may have been present. When discussing a loss of energy as the stream exits the bottle, I shared a journal article from The Physics Teacher: “Determining the Coefficient of Discharge for a Draining Container.” This article was a great way to finish the fluids unit in that it was accessible to the students and demonstrated the limitations of our fluid dynamics model.
##fluids ##practicumlab
Today, AP Physics 2 students had their first major exam. This is the first time students were directly exposed to the different standards-based grading methodology that I’m trying with AP Physics 2. When the look at the grade book, they will see something like this:
Over time, all of the AP Physics Big Ideas and Enduring Understandings will be represented. To maintain the focus on complex problems that integrate multiple concepts, students taking reassessments will take another entire exam that covers all relevant enduring understandings.
If nothing else, I think reporting learning in this manner will reinforce the big ideas that connect the varied topics that comprise AP Physics 2.
##sbar
Today, AP Physics 2 students used their computational models for projectile motion of a fluid stream to predict where on the floor to place their cup to catch the water from their 2L bottle with a hole in the side. When I planned this lab practicum over the summer, I was disappointed that we would be developing a computational model for a problem that is fairly easy to solve algebraically. Last year, we used a computational model for a lab practicum where the algebraic solution was beyond most students. I recently remembered advice given to me from a physicist at Fermilab: students must understanding that computational models must be verified against known outcomes before they are used to calculate unknown outcomes. I emphasized this point and encouraged students to check their computational model with an algebraic solution solved by hand. While I mentioned this yesterday, I bring it up again since, today, a student remarked that the computational model was off by 5 cm. He and I were both stumped by this since the projectile motion part of the model is fairly straightforward. Thankfully, another student found the bug. The origin of the model was set to the bottom center of the bottle. The water droplet exiting the hole started a displacement of half the bottle’s width from the origin. The bottle’s width was set to 10 cm. The reported position of the water droplet hitting the floor was based on the origin being located at the center of the bottle and not at the starting position of the water droplet. The student that found the bug quickly fixed it by setting the width of the bottle and enclosed column of water to 0 cm! While totally unplanned, this nicely emphasized the importance of verifying one’s computational model! I have since fixed my model by positioning the initial x position of the water droplet at the origin.
I was so busy today running around watching students demonstrate their prediction and passing out towels, that I forgot to take photos. Thankfully, @anna_kraftson was observing my class and did!
##practicumlab ##fluids ##setbacks ##computationalmodels ##coffeescript ##glowscript
Today, AP Physics 2 students had the first opportunity to modify an existing computational model to prepare for tomorrow’s lab practicum. Tomorrow’s lab practicum is to predict where on the floor to place a cup such that the cup catches the water exiting from a 2L-bottle filled to the specified level and placed the specified distance from the floor. The computation model that I provided implements projectile motion and provides the framework for modeling the bottle and water. Students have to add the physics to calculate the initial velocity of the water. I also emphasized the importance of verifying your model against a known outcome before using it to predict an unknown outcome. Students are using Friday’s quiz as a test case for their model and verifying the prediction of the model against their hand calculations. While this lab practicum doesn’t require the use of a computational model, it is another representation in which the students demonstrate their understanding.
We will see how wet the floor gets tomorrow!
##fluids ##practicumlab ##coffeescript ##glowscript ##chromebooks