Tuesday, April 13, 2021

Teeeeter Totr

Just a quick balanced torque puzzle. It's really a test of whether or not one truly accepts the concept of center of mass.

Nothing exotic going on. The meterstick is uniform. Sufficient information is provided to solve the puzzle. It can be confounding to students.

Teeeeter Totr - HTML export | movie export

UPDATE: Among the many things I can count on life is that virtually any mechanics demo I might share here has already been done better by the inimitable Dan Burns. For example:

Sunday, April 11, 2021

RT;DL Pixel Peeping

Screens. When I was in school, screens were reflective white, flat curtains pulled down from retractible rolls when the teacher was going to show an educational film on the reel projector they shared with the other teachers at the school.

At home, screens were cathode ray tubes in which a spray of electrons, steered by magnetic fields and attenuated by a shadow mask, struck red, green, and blue phosphors. The high-pitched noise given off by the electronics of a CRT TV monitor create physical pain in modern-day students. TV watchers of a certain age somehow tuned that 10 kHz+ whine out.

Today, screens are everywhere, and virtually all are based on light-emitting diodes. But the RGB nature of color imaging remain. That's what this activity is about.

Color mixing and pixel geometry. Surprising enough and instructional enough to be worthwhile.


Pixel Peeping Student Document (Google Docs copy link)

Pixel Peeping Magnifier Observations - HTML export  |  Movie export
(media links are included in the student document)

The PhyzSommelier says this activity pairs nicely with

PhyzLab Springboard - Fun With Colors (Google Docs copy link)


Saturday, April 10, 2021

Thursday, April 08, 2021

In the George Floyd trial: Audio Pareidolia

Humans are so good at finding patterns, we often find patterns where none exist. This phenomenon is referred to as pareidolia. 

Add to this the power of suggestion, and things get even more interesting. The back masking panic was fueled by audio pareidolia. As was EVP: electronic voice phenomena, a means by which ghost hunters fool themselves and others.

I made a presentation on the audio version of this phenomenon and deployed it during our unit on waves and sound.

It was all good, wholesome, laughable fun. And then it showed up in the trial of Derek Chauvin. I have updated the presentation to reflect this latest incident. I placed it at the vary end so that by the time you get there, you'll recognize exactly what's going on.

Back Masking (HTML export)