Thursday, May 28, 2015

99.96% Black

A black purer than Ivory soap.

The substance, which is made out of carbon nanotubes and grows on aluminum foil, appears almost like a black hole because, in a way, it acts similarly to our eyes. Black holes produce such a large gravitational pull that light cannot escape it. Vantablack, on the other hand, absorbs so much light, roughly 99.96 percent, that it appears just as dark as a black hole. Even though the two objects are very different, they both confuse our eyes, which are not used to such an utter absence of light.

Click over to the article to see an image. Black can be a difficult subject for photographers.
This Material is So Black That Your Eyes Can't Fully Understand It

What else is black of late on the Internet?

Strindberg's need.

This Norah Jones track.

Monday, May 25, 2015

Colleague and Friend: Alec Hodgins

Point of Personal Privilege.

Alec Hodgins taught French at Rio Americano High School from 1988 to 2014. For virtually all of that time, he and I were either next-door classroom neighbors or across the small courtyard neighbors. In October, 2014, he went out on medical leave. A few weeks ago, he succumbed to depression. Those of us who knew him and loved him were devastated.

The comment I sherec with friends was, "Alec Hodgins was a unique soul whose creativity and diligence made him a pillar of Rio Americano High School. He was passionate about teaching French and playful in doing so. He inspired students. Deeply and permanently. In ways most teachers never will. The school is significantly diminished without his enthusiasm and energy."

Among other things, he was the motivation that energized my 15'x30' mural of Pink Floyd's Dark Side of the Moon outside my classroom.

I assembled a montage to convey the Alec Hodgins I got to know over the course of the 26 years I worked with him. It was included at a celebration of life commemoration we held after school last week.

Since the, a few more images were found. A slightly modified version of the presentation is shown below. It's neither brief nor comprehensive.

Alec Hodgins - Wish You Were Here

High school cultures are nothing if not ephemeral. If you went into a profession hoping to leave a legacy, you would have made a mistake in choosing high school instruction.

Physical manifestations of Alec will remain with our adjacent murals. He also instigated a scheme to develop Rio decals (window stickers) to help promote our Blue Ribbon school in the face of districtwide declining enrollment coincident with The Great Recession. He made a nice set of wooden return trays (for graded student work) and mini shelves so I could display the framed awards bestowed upon me and my students: The Wall of Ego.

More importantly, Alec's energy and empathy live on within those of us who valued his many admirable qualities.

If you need a moment at the end of the year

The NOVA episode devoted to the work of James "The Amazing" Randi makes a nice coda to any science course.

In the end, skepticism and critical thinking are important elements we hope we instilled during the year and will remain with our students long after the formula for kinetic energy has faded.

The full video is on YouTube here:
NOVA: James Randi's Secrets of the Psychics

An accompanying question sheet to help keep everyone engaged can be found here:
Video Questions for James Randi's Secrets of the Psychics.

More skepticism in the classroom lessons and links can be accessed from my Skepticism in the Classroom page.

Sunday, May 03, 2015

Kinetic Karnival links updated

It seems MySpace (yes, it still exists) changed all the URLs to their extant content. I'd snark, but kicking MySpace at this point just seems merciless and unfair.

Jearl Walker's excellent Kinetic Karnival videos are warehoused there, so all the links I had to his page and videos went bad.

The original post highlighting his videos and my curriculum was this:
Jearl Walker's Kinetic Kanival

Down the rabbit hole: Well, the links to my question sheets were equally outdated. So I've updated them. The linked PDFs are not always the most current, but should be fully-functional and correct.

Happily, I've updated the links, so this post is once again operational, as is the link in the right margin of this blog.

If you see that something's gone awry, please let me know. I'll do my best to get things repaired ASAP.

Monday, April 20, 2015

Disassemble, Yes!

As a child of the ’80s, I saw Short Circuit more times than I can count. To this day whenever I take something apart I hear the terrified Number 5 yelling, "Disassemble?! No!!" as he realizes what it would mean for him. But I still take things apart, because it is fun.

There have been many things I've collected (okay, maybe call it hoarded) over the years for use in my classroom. Some I have specific and immediate uses for .... some not so much. I still have part of the framing from a holiday light lawn sculpture of a snowman that I just know will be perfect for something, someday.

I finally got the time this year to disassemble an old toaster, hair dryer and space heater. I reference these appliances when I teach electricity as a practical example of the conversion of electric energy to thermal energy. By the time we get to that, students have often had personal experience with that conversion when they leave their circuits on too long and touch hot resistors.

Even though we've talked about the dissipation of heat from electrical circuits I don't think my students believed me until they saw all those coils of wire. It was a simple thing to take them apart (they weren't working anyway) but many of my students were just in awe of seeing the inside of something. Little do they know they get to do it next week.

Now that our current electricity unit has come and gone we have moved on to electromagnetism. I have my students make a speaker out of paper using a paper template I made (pdf or google doc), a doughnut magnet and a coil of magnetic wire. Its a simple build based on Modesto Tamez's activity from the Exploratorium, but the students love it every year. It can be expanded by asking students to improve the design, increase the volume or efficiency. I've also seen a headphone project follow this for which students have to make their own working headphones based on this speaker design. (NGSS Science & Engineering Practice right there!)

This year I'm adding a "Dissecting Headphones" lab to my unit. Thanks to RAFT I scored a gross of cheap ear bud headphones several years ago that I've been holding on to (hoarding again). Each pair of students will get a set of headphones so that they each get to dissect one ear bud. The instructions go step by step for these particular headphones and lead students all the way to the small magnet and coil. I've done it with high school aged students before and despite building the paper speaker only a few minutes before, they are shocked—shocked—that their ear buds work the same way. They use classroom scissors and a straight pin; they can use wire cutters too, but they are not required.

Suddenly they all start making connections. "This is how a microphone works, too!" and "That's why my headphones attract paperclips!" are heard all over the room. And it's magical.

The lab my students will do this week includes both the "Make A Speaker" and "Dissecting Headphones" labs in one file available as a pdf or google doc.

Sunday, April 05, 2015

Canvas to Keynote conversion update

It began in October, 2012. Full story here.

At the outset, it looked like this.

In June, 2013, it looked like this.

Last year (April 2014), it looked like this.

Now (April 2015) it looks like this.

Progress. As sure as it is slow.

Sometimes demos go wrong—that doesn't make demos wrong

If you're hip enough to have tuned into this blog, you've probably seen the viral video of the cinder-block smash demo gone wrong. I'm not linking to it directly, because it's not any fun to watch. Of course, in this modern era, you can find versions of this incident from multiple angles.

I have mixed feelings about this demo and have never done it, myself. But I think Greg Schwanbeck makes a powerful argument against the knee-jerk reaction that will likely follow.

Please Don't Ban My … Physics Demos From Schools

And despite the date, this was no April Fool's joke.

Paly teacher burned in science experiment accident

Details are sketchy, so I'm not sure what conclusions can be drawn. No matter how often we've done some of these demos, it's imperative to remember the risk involved.

We wish speedy and full recoveries for both injured teachers.

And, OK; I'll give you a bed of nails blooper—direct from my talented and enthusiastic colleague, The Skeptical Teacher Matt Lowry. (Things get real at about 5:25.) He has recovered!

Tuesday, March 31, 2015

Van de Graaff Ping Pong

As played with a bundle of silk thread, as you do.

This gem comes to The Blog of Phyz from Inderkum's Jessica Downing, an upbeat, resourceful teacher at the most amazing high school in America.

It's a nice sequence of polarization, charging, repulsion, and discharging—rinse and repeat. It's like a puppy playing fetch.

This video below is slow-motion. This link will take you to the normal-speed version.

Van de Graaff Demo

Quantum locking

I guess I missed this one the first time around. Better late than never. I've seen magnetic levitation, but it didn't look like this.

Quantum Levitation

Uploaded on Oct 16, 2011
Video courtesy of the Association of Science-Technology Centers (ASTC), representing the science center and museum field worldwide. To learn more, visit Follow us on Twitter: @ScienceCenters.

Acoustic extinguisher

Low frequency sound douses a flame. I haven't seen a good explanation. In NGSSpeak, I'd say what we have here is engineering without a full scientific explanation. The explanation that, "it separates the oxygen from the fuel" is not working for me. Moving so much air that the temperature of the reactants is reduced below the combustion temperature seems more plausible.

Here's the article from Sputnik International

Pump Up the Bass to Douse a Blaze: Mason Students' Invention Fights Fires