Saturday, December 03, 2016

Roll the dice

Studying the Law of Universal Gravitation can be heavy (ba dum tss) for students. Each year my students push through the long equations and we go without a lab for about a week. That's pretty unusual in my classes and they can feel the change. If a student asks why we aren't doing a lab I usually reply, "Well I can't haul Jupiter in here to measure it so ...."

Practice problems were always difficult for students, more about living by the Order of Operations (PEMDAS) then actually understanding the problem. Some would take one look at that period of revolution equation and say "No, nuh uh, not gonna make me. Nope."

I tried to make them fun by creating word problems. It wasn't just calculating the Force of Gravity between you and Jupiter, "Let's compare that to the Force of Gravity between you and the doctor that delivered you! Jupiter's gravity doesn't affect you and astrology is bunk!" But still going through problems together wasn't engaging students.

Your birth Mass (kg)Jupiter & Doctor (kg)closest distance (m)Universal Gravitational ConstantForce of Gravity (N)
A few years ago I had an idea to make our practice calculations into a dice game. One di has problems to solve and the other different planets. There are actually two different planet di so that students can choose. Here is a print ready file, I suggest thicker paper to give it some structure. They take some time to assemble but you can use them for years to come.

The kids loved it. They probably work through more practice problems than they would have if I had just supplied them with certain ones to do and they were very invested in letting chance choose which they would calculate. A new development this year was that they are so used to checking their answers with me while they whiteboard they wanted to know the "answer." That was harder to do as I walked around the room since there were so many variations. I decided to create and project an answer chart in Excel.

Depending on how your school or district is defining "physics" from the NGSS framework you may or may not be finding yourself teaching more Earth & Space Science. We had our own sort of NGSS Draft among Chemistry, Physics and Biology trying to divide up the Earth & Space Science topics. In my district Physics ended up, rightly so I feel, with HS-ESS1-4:

HS-ESS1-4.Use mathematical or computational representations to predict the motion of orbiting objects in the solar system.[Clarification Statement: Emphasis is on Newtonian gravitational laws governing orbital motions, which apply to human-made satellites as well as planets and moons.] [Assessment Boundary: Mathematical representations for the gravitational attraction of bodies and Kepler’s Laws of orbital motions should not deal with more than two bodies, nor involve calculus.]
This goes well with HS-PS2-4 about the Law of Universal Gravitation:

HS-PS2-4.Use mathematical representations of Newton’s Law of Gravitation and Coulomb’s Law to describe and predict the gravitational and electrostatic forces between objects. [Clarification Statement: Emphasis is on both quantitative and conceptual descriptions of gravitational and electric fields.] [Assessment Boundary: Assessment is limited to systems with two objects.]
I'm still working on adding more of Kepler's Laws into the curriculum, there is an outline here on this Disciplinary Core Idea about it.

Wednesday, November 23, 2016

Understanding Even More Car Crashes

I posted a lesson to accompany the IIHS "classic", Understanding Car Crashes a few years ago. If that post doesn't ring a bell, click here. Links to the video and lesson can be found in that original post.

A related story percolated up through my social media feed a few days ago. National Public Radio's Goats and Soda produced a story about the Latin New Car Assessment Program (NCAP). NCAP ran a crash test that pitted entry level Nissan vehicles against each other: The American Versa vs. the Mexican Tsura.

Crash Test Dummies Show The Difference Between Cars In Mexico And U.S.

Here's the video:

2015 Nissan Tsura vs. 2016 Nissan Versa

[Executive summary: The American passenger fares much better than Mexican passenger.]

When news of the test went public, Nissan announced that Nissan Mexico would discontinue sales of the Tsura in a few months.

It could be that the timing of Nissan's announcement coinciding with NCAP's test was... coincidental. That is a real possibility.

On a tangentially related oldie-but-goodie, some folks think cars from yesteryear were tanks that would decimate today's light-weight counterparts. An instuctive crash test pits a 2009 Impala against a 1959 Bel Air. Watch the video to see how that one turned out.

2009 Chevrolet Impala vs. 1959 Chevrolet Bel Air

If you're a classic car enthusiast, drive carefully!

The lesson I constructed includes an exercise in which students look up the IIHS safety test of the car they drive (or are commonly driven in).

Saturday, November 19, 2016

Inertia of Fall Leaves

This video has gone viral with good reason, its super cool.

In this slow mo video we see an amazing example of inertia as the bed of leaves remain as the net is lowered beneath them. What else can you discuss about with this video?

Evolution of Physics Curriculum

As I NGSSify my curriculum I find myself removing some pieces of my curriculum that I've done for a long time. Sometimes they are replaced with better activities, sometimes they were dead weight, sometimes I'm sad to see them go. I'm not there yet but it is a process for which we still have several years as the NGSS assessments might be ready by 2018. You've got some time.

While making these curriculum choices I ask myself:
- Does this activity align with NGSS in content (addressing a Discipline Core Idea or Performance Expectation)?
- Or does it align with the Science & Engineering Skills?
- If not is it an essential skill to support NGSS acquisition? (i.e. graph making)
- Is it content that they need to support late NGSS content? (i.e. Newton's 1st and 3rd Laws)

As we approach the middle of the 2nd quarter I find that I am "behind" my past self by almost two weeks. This has meant moving Energy, Work & Power to second semester rather than cram it in first semester. My time crunch is due to a few big changes in my classroom that are still getting the kinks worked out:

1) This year I do not have required homework other than finishing labs. There are some "suggested homework" each night and the problems that I really like are worked into the class period. I suggest that struggling students do the homework each night, it is very briefly reviewed each day because less than a quarter of the students do it nightly. A lot of my students are in more than one AP class, sometimes I am their only non AP class, so if they are understanding the material they don't have to "waste" time doing homework if they don't need it.

2) So how do students know they should try the optional homework? Each week students take a low-stake weekly quiz based on the homework. That way they and I know how they well they are understanding the concepts. I grade their notebooks at the same time so that I can look over their labs for the week. Timing has been an issue so far. Sometimes the quizzes are too long and take most of the period. Absences have also delayed getting the quizzes passed back so in the future I think I will excuse the absent kids. This mean I don't have a chance to see how they are doing before the big assessment and the other quizzes in that category count more but it should improve the pass back time. I want students to have near immediate feedback on these formative assessments. I have been crudely tracking the standards addressed in each quiz in an Excel sheet but they have not been in a way that can be easily shared.

3) Students complete problems on whiteboards in small groups. This has been successful but sometimes not universally so depending on a few things. Some students dominate whiteboards just as they do labs so now I ask students to pass the marker on after each problem. Some students don't feel confident enough in their abilities to problem solve while others are watching. If the group is motivated to be "done" as fast as possible then they miss out on the conversations and growth to get something written ASAP. Yet some of the best problem solving think-out-loud collaborating discussions my students have ever had have taken place this year. They correct each other by citing previous activities, "Remember when she said this? Remember that one lab we did?".

Overall I like the changes and will be keeping them, with some revisions. I need to focus on making sure the weekly quizzes tackle common misconceptions just as much as calculation practice. I need to emphasize and normalize doing the suggested homework without making it seem required. It should feel like an opportunity for students; I want struggling students to want to do it to improve themselves. For whiteboards we have to set up community expectations that include all the students of the group at once and makes it a safe space for all of them to try, make mistakes and try again. And I have to work on my timing by probably further cutting some material. But that will be a topic for another post ...

Friday, November 11, 2016

Did the Coyote Catch the Roadrunner?

Fans of my Roadrunner Physics website might be wondering this after the site went black in early October. My school changed website hosts, orphaning it. Fortunately, our IT department transferred it intact to our new hosting service, thus once again thwarting the Coyote's plans. You can click on the above hyperlink or copy and paste the URL:

They also transferred my internationally popular Science on the Simpsons website. You can click on the hyperlink or go to this URL:

Unfortunately, some of the formatting of the clip descriptions is cut off.  I hope to have this fixed soon. In the meantime, download your favorite clips so you don't have to worry about the site being inaccessible in the future. These clips are posted in accordance with the fair use provisions of the copyright act. They are for educational purposes, not entertainment. However, if your students are entertained by your creative educational use of them, that is OK.
 I was inspired to create the Roadrunner website by Dean Baird's description of his use of Roadrunner cartoons to teach physics. He posted specific information about what episodes had useful clips. I used this and my own personal research to assemble the collection that I use on the first day of class. Roadrunner cartoons show my students that they already know a lot about physics. Roadrunner cartoons are humorous because they defy the laws of physics. When the students chuckle at a scene, they are revealing that they have an inherent sense of some of the rules that the universe operates under. Sometimes we focus too much on student misconceptions. Often these are incomplete thoughts that are closer to the actual physics concepts than we may realize when we focus on what is wrong about the ideas. One example is the student belief that a bullet receives a larger force than the gun. I find it more effective to acknowledge the student's belief that SOMETHING is different about the interaction. That something is of course the acceleration because of the difference in the mass.

The Science on the Simpsons website has its origins when I collected clips on a VHS tape to show my Earth/Space Science class back in the 90s. Other teachers would borrow it and I often had to hunt it down when I wanted to show it. The Coriolis Effect and Bart's Comet clips were the most popular. This motivated me to create digital clips from my Simpsons DVD collection and post them online for every teacher to use. Since then I have interacted with people from around the world who send me appreciation emails and ideas for new clips. The Simpsons are popular in Germany, Spain, Great Britain, and Australia. A few teachers used the site to support their master's thesis. Another teacher wrote an article about using the Simpsons to teach science that was published in the Spanish Newsweek. He runs a Science on the Simpsons Facebook page too. I even got a congratulatory note from one of the Simpsons executive producers:

"Hi, Dan.  My brother-in-law works at Rockefeller U. and sent me your Simpsons/physics link.  I love it and sent it to some of my colleagues who actually know something about science.  Great work -- I hope people use it.

Rob LaZebnik
Co-Executive Producer
"The Simpsons"
10201 W. Pico Blvd.
LA, CA  90035

I have been receiving emails from distraught teachers looking for the Science on the Simpsons and Roadrunner Physics websites. Please spread the word that they have moved. That would be "Excellent".

Sunday, November 06, 2016

Before the Flood

I am grateful to Bree Barnett Dreyfuss and Dan Burns for keeping The Blog of Phyz vibrant while I hunker down with the development of basic (non-lab based) Earth Science curriculum and juggle four preps, two of which are AP.

Last Sunday, National Geographic premiered Leonardo DiCaprio's Before the Flood, a worldwide journey of discovery, doom, and hope relating to the current state of climate change science and politics. He's not putting this highly-produced, cinematically stunning production behind any paywalls/ DiCaprio means for you to see it.

National Geographic: Before the Flood HD (Complete: 1h35m) TV-14

As it happens, my Earth Science students are in the midst of their unit on Climate, to be followed by their unit on Human Impact. Al Gore's An Inconvenient Truth and Alanis Morissette's Global Warming: The Signs and the Science are over a decade old now.

So I tinkered and toiled to develop a set of video questions to keep the students engaged in this otherwise passive activity. The intent is that it's enough to keep them focused but not so much they fall behind during the screening. This is what I produced.

Before the Flood Video Questions (PDF)

Another nice (and recent) production is National Geographic's Bill Nye's Global Meltdown (feat. Arnold Schwarzenegger). I leave it to others do develop curriculum for that one.

Tuesday, November 01, 2016

Science Films

The Museum of Moving Images has created this "Science & Film" teacher guide with a list of short science-related films for the classroom organized by discipline.
From their introduction page: 
"Filmmakers are making many different types of films and Museum of the Moving Image publishes Sloan Science & Film to enhance public understanding of science through film. This is a guide to 46 short narrative (fiction) films–all supported by the Alfred P. Sloan Foundation's nationwide film program–available for streaming in your classroom, which explore science and technology themes and characters. Our goal is to help teachers engage elementary, middle, and high school students in STEM learning.
- Films range from 4 to 33 minutes, averaging 20 minutes in length
- Each film correlates with National Standards, New York State Standards, and New York City Science Scope and Sequence (with a comprehensive appendix of all three attached), and can be customized to meet your needs
- Subjects include astronomy, biology, chemistry, ecology, evolution, genetics, mathematics, physics, psychology, technology, and the history of science
- Included with each film are possible questions to explore and science resources for further engagement"

The Physics portion starts on page 35 by the way.

Science & Engineering Practices poster

The Synopsis Outreach Foundation Sciencepalooza has worked with a graphic artist to create a visual of the NGSS Science & Engineering Practices poster. Its a great addition to your classroom and available here. A preview is below, I suggest you download it!

Saturday, October 29, 2016

Solar Tile Impact

Much of the tech world is abuzz with Elon Musk's announcement that Tesla will be producing glass solar roof tiles. They look as good as normal tile or slate or other roof materials but they are inconspicuous solar tiles. There are tons of articles out there but this video posted to @TeslaMotors twitter page caught my eye:

A kettlebell (I assume at least 10 lbs) is shown falling directly onto each tile sample being dropped from the same height and edited to be at the same time. The different materials respond differently; while the solar cell may not be functional after such a hit it structurally remains in one piece unlike the others.  But I was caught by the varying rebound heights. I downloaded the video and opened it in Vernier's Video Physics app on my iPad and started playing with it. This is the first time I had used it to follow an object's entire motion so its not the cleanest. I tracked the first kettlebell that fell onto the Terra Cotta tile on the far left:

I plan to use this in my energy unit. I can ask students to discuss the change in potential energy for each of the kettle bells as they fall. Students could look at the rebound height for each sample and discuss the loss of energy in each case. I'm hoping students will realize that the loss in potential energy means that the energy has gone elsewhere. You could discuss common product testing, brittle materials vs elastic ones, momentum and more. If you have one-to-one devices you could have students do the same analysis for each material so that they can get the same information for each.

Wednesday, October 26, 2016

This time machine makes a second last for twelve minutes

And it's only $2500 for the privilege.
Chronos 1.4 is the brainchild of engineer David Kronstein, who first demonstrated the camera’s hardware and recording capabilities with a production-level prototype under his YouTube handle ‘tesla500.’ The camera can record 1,057 fps at 1280 x 1024, and up to 21,650 fps at lower resolutions.
The math pencils out as follows:

When viewed at the standard video frame rate of 30 frames per second (fps), 21,650 frames would take about 722 seconds, or 12 minutes to watch.

The iPhone can natively capture 240 fps, which slows 1 second of action into (240/30) 8 seconds of viewing.

DPReview has an article on the Chronos 1.4, and there's a demo video as well.

Chronos High Speed Sneak Peek

UPDATE: Watching the sneak peek makes me think the native playback rate on this camera's files is 60 fps, in which case 1 second of action will blow by in a mere 6 minutes at the highest frame rate.

UPDATE 11/25/16: The Kickstarter campaign goal was achieved in five hours.