Apologies

No, I'm sorry to say I didn't complete your website update, your tri-fold brochure, the finishing work for that model that needs to go in the mail ASAP, my taxes, or any of the other 18 deliverables on my punch list.

I did, however build a desktop laser interferometer today with a bunch of high school kids.  Pretty cool - it totally worked, although you can't actually see the dark lines in the diffraction pattern on the paper in the photo.  We also built some bridges from straws and tape - about as fun as it  can get without lasers.

Lenses and mirrors and lasers, oh my!

"Nobody said the span needed to be >1 inch."

The bridge session kids didn't realize it until the end of the session that the whole purpose of the exercise was to follow rules but look for loopholes and ask for information that they needed.  Their first task was to line up along one wall in order of sequential birth month and date without anybody speaking. A lot of mad hand gesturing happened before they realized they weren't prohibited from writing on the whiteboard behind them.

And thus concludes another STEM-con. (Science, Technology, Engineering, and Math!) Back to my regularly scheduled to-do list.

Dancing with the Salts

More geekiness, in part brought on by the trip to LIGO last week.  My son came home Thursday with two friends and a goal of doing a special experiment and presentation for extra credit for their science class.  Their science teacher had introduced Cymatics and showed them this video on You-Tube:



They rigged up a tone generator from the computer and I helped them cable it into the home stereo. We took a trip to Goodwill, where we found a few big speakers that could be cannibalized ($2.17 total - what a deal!) A little wiring and soldering later, we were able to dial up any frequency and crank it up. Earplugs.

It took some fiddling to get a plate system that would work, but the kids eventually ended with a system that worked and the salt did indeed dance. It wasn't anywhere near as elaborate as the video, but they could see patterns and they did change as they ranged the tones.

With this success, then my daughter described the LIGO demo where they had taped a tiny mirror to the plate in a similar setup and shot a laser pointer at it. As the sound changed, the reflected spot on the wall went crazy due to the vibrating plate! We replicated this with great success, although photographing it was less than representative.

These are called Lissajous figures.  Much fun for me, as I got to play the role of technical consultant.  I could also see the lights flickering behind the eyes of the kids.  I hope they are sparked to further explore. Meanwhile, I must go vacuum the living room...and buy another box of salt.