Day 123: County-Wide Institute Day

Dr. Brett Moudling, who was a contribution to the Framework for K-12 Science Education, which is the foundation for Next Generation Science Standards, was the keynote speaker at today’s county-wide institute day. I liked how he groups the cross-cutting concepts into three related categories:

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He also categorized the science and engineering practices into three categories: Gathering, Reasoning, and Communicating.

I also attended a break-out session led by Dr. Moudling. Part of the session was to make observations and build explanations for the observed phenomenon of ice cubes in isopropanol. It was a fascinating activity as so many different phenomena were observed. My group focused on density effects, index of refraction, and melting characteristics. The entire session had a long discussion about where the ice cube floats between the alcohol and water boundary. I quickly calculated the buoyancy and I’m fairly confident that 40% of the cube would be in the alcohol and 60% in the water. I don’t think I convinced the session of this as we had contradicting observations. After the session, my group added more ice and we’re pretty sure of the 40/60 split. Maybe that was confirmation bias, however. I think this would be a great activity for AP Physics 2 next year.

The final session was by Dr. Pete Ludovice from Georgia Tech. He is a chemical engineering professor and a stand-up comedian. His topic was “Making Science Fun – Humor in the Classroom.” It was a very entertaining session and a great way to end the day.

  ##ngss ##buoyancy  

Day 121: Simple Harmonic Motion Paradigm Lab

For simple harmonic motion, I like to split the introduction into two labs. The first is qualitative and focuses on graphical relationships. The second quantitative and focuses on the mathematical models for those graphical relationships. Today, we started the Oscillating Particle Model (OPM) with the first lab. I have three types of simple harmonic oscillators: a horizontal spring oscillator, a vertical spring oscillator, and a pendulum. I assign two groups to each type and have them answer the following questions and investigate how changing either the mass or amplitude (for springs) or mass or length (for pendulums) affects their answers.

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We started to share our results on whiteboards. The chain of reasoning and discussion that resulted was fantastic. One group led the class through the thought process that the maximum potential energy of the system doesn’t change when the mass of the horizontal oscillator is changed while the amplitude is constant. From that they jumped to the conclusion that the maximum kinetic energy of the system must also not change. Then, on-the-fly, they reversed their original statement based on limited data that increasing the mass of the oscillator decreased the velocity in a linear fashion. Now analyzing the system from an energy perspective, they realized that as the mass increase the square of the velocity must decrease. Great stuff!

  ##paradigmlab ##opm ##whiteboarding  

Day 119: Measuring the Wavelength of a Laser

Today we continued our investigation of diffraction and interference. The lab focused first on qualitative observations of single slits, double slits, and diffraction gradings of various widths and with red and green lasers. The final part of the lab was to make the necessary measurements and then calculate the wavelength of the He-Ne laser. Even just using the classroom meter sticks, students were within 10 nm of the actual wavelength. I think they are starting to appreciate how this phenomenon can be used to create an incredible precise measuring instrument!

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  ##physicaloptics ##practicumlab  

Day 118: Unpacking NGSS

Today was another meeting of the district-wide Science Curriculum Team. Today we started unpacking the Life Science standards. I found it very interesting since Life Sciences is not my strength and I learned a lot about how we currently teach biology in middle school and high school and how it will be different in the future. My group didn’t come up with anything too revolutionary, but at least one of the other groups did. I’ll have to check out their idea!

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(I forgot to take a photo; so, I”m stealing @anna_kraftson‘s

  ##local ##ngss  

Day 117: Physical Optics Introduction

Today we started physical optics. This is the first truly new unit to all students this semester. The lesson was a series of a proposed scenario; prediction based on current understanding of light; demonstration of the scenario; and finally conceptual, geometric, and mathematical explanations. One lab stand and a laser was all that was needed for the demonstrations. I love have the laser incident on the thin wire and illustrating diffraction on the wall, and students are amazed by the results.

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Two excellent questions were asked for which I didn’t have answers. One: when light is destructively interfering and forming a minimum on the wall, where did that energy go? Two: while we observe that light diffracts, as do other waves, why do they diffract? Please feel free to pass along any answers and save me some research (especially, a conceptual explanation of the second question)!

  ##physicaloptics