Monday, May 30, 2022

Mirages [Lab Springboard]

This activity mixes a lab activity with a springboard lesson to explore the optics and perception of mirages and looming (inferior and superior images).

The recommended equipment is Arbor Scientific's Laser Viewing Tank.

To make this lesson work, you begin by setting up the "skinny fish tank" with water and corn syrup or sugar. Then you go through the "paper and pencil" lesson about the optics of mirages, and why they are perceived as bodies of water. Then it's time to hit the tank with the lasers to see how the index gradient causes the beam to curve. By then, the connection between curving light rays and mirages is understood.

Wednesday, May 25, 2022

Understanding Rainbows [Springboard]

Second only to "Why the Sky is Blue" in ambition, I would rank this as one of the best lessons I have authored. 

With rainbows, the physics is relatively simple (once you've covered refraction and dispersion) and the geometry is simple. Putting them together? Well, this is a four-page lesson. It takes a bit of time to work out the details.

The post-lesson "extras" in the presentation are amusing rewards. The "Double Rainbow" video has mostly faded from cultural awareness among students, so it's new to them! Is the dramatic interpretation over the top? Yes it is.
Student document (print-friendly Google Docs file on Google Drive)
Instructional presentation (link embedded in answer key)
Answer key

Diversion into Dispersion [Lab Springboard]

This is an exploration of differential refraction: white light is dispersed into a spectrum by a prism. The activity explores the physics behind dispersion before giving a name to the phenomenon. 

Pink Floyd's classic album cover for Dark Side of the Moon is evaluated: what's right and what's wrong with the illustration? [I painted a 10' x 30' mural of Storm Thorgerson's image outside my physics classroom.]

Student document (print-friendly Google Docs file on Google Drive)
Instructional presentation (link embedded in answer key)
Answer key

Tuesday, May 24, 2022

Index of Refraction [Springboard]

Examples of vacuum, glass, and gallium phosphide are used as we define and apply the index of refraction. Ratios of speeds, wavelengths, and sines of angles are involved. Interesting graphical tangents are visited, and a numerical sample problem is included.

Student document (print-friendly Google Docs file on Google Drive)
Instructional presentation (link embedded in answer key)
Answer key

Diversion into Refraction [Lab Springboard]

This activity acts as an introduction to refraction. Prior knowledge: sound travels faster in solids (like steel) than it does in air. So what about light? Does it travel faster in transparent solids (like glass) than it does in air? Isaac Newton thought so.

We use the classic "car on carpet" model to explore the question. A toy car is rolled at an oblique angle down a ramp. There are hard surfaces, and there are carpeted surfaces. The direction of the car's path is affected by moving through the different surfaces.

Wednesday, May 11, 2022

New Electromagnetism Lessons Added

Right hand rules in high school physics do not bring me great joy. I cringed when The Physics Teacher ran a photoessay from an instructor who photographed students contorting hands during an exam. (A cursory search for this article was unsuccessful. I hope it was expunged.) 

Nevertheless, 3-D geometry cannot be avoided when studying magnetic fields and forces. In the ├śrsted's discovery lab, students develop a right hand rule relating to current and the magnetic field it produces. That was Right Hand Rule #1.

This activity relates current, external magnetic field, and magnetic force. Right Hand Rule #2.

Saturday, May 7, 2022

Picture a Scientist

I thought this needed a question set, so I wrote one. It's now the featured free resource at The Lessons of Phyz store on Teachers Pay Teachers.

Thursday, May 5, 2022

The Secrets of Quantum Physics

Professor of physics Jim Al-Khalili investigates the most accurate and yet perplexing scientific theory ever - quantum physics. The program's two episodes
stream on Amazon Prime. YouTube links have also been embedded in the text below and the titles in the student documents.

The history of and battle over quantum entanglement. Albert Einstein hated the idea that nature, at its most fundamental level, is governed by chance. Professor Jim Al-Khalili reveals how, in the 1930s, Einstein thought he'd found a fatal flaw in quantum physics because it implies that subatomic particles can communicate faster than light in defiance of the theory of relativity. Delightful bonus: "Tangled Up With You" by Eliza's Uncertainty, a perfect addition to your modern physics playlist.