I’ve just posted a new episode of my podcast, Science Teaching Tips geared at secondary schoool science teachers.

In this episode, What’s Your Story? veteran science teacher Carol Murphy talks about how she uses storytelling in her science classes.
Enjoy!

These are produced through the Exploratorium’s Teacher Institute.

I’ve been Simpsonized! Just wanted to add this for fun!

I just have to add a plug for an amazing resource, the Wikimedia Commons. I try to use open-source images on this blog, and this is where I get them. They’ve also been really valuable to us at the Exploratorium in terms of getting images that we don’t have to pay to use — it includes a lot of scientific images. Many images that are part of US government funded research projects are automatically part of the public domain. How great!

Wikimedia also includes, of course, Wikipedia, Wikinews, and Wikibooks. I’d be curious to hear people’s opinions on any of these, or other Wikimedia sites.

I want to point out a neat-o blog, Cocktail Party Physics by Jennifer Ouellette. This blog has a lot of prolific material about physics, and is very popular. She recently visited San Francisco and here is her post about the Exploratorium.

That post concludes, “where everyone was encouraged to discover more about the topic at hand, pursue their own lines of inquiry, question assumptions and stereotypes (including their own ingrained biases, per that toilet drinking fountain), and test their theories in a hands-on fashion — so that their opinions actually have some substantial basis in fact. We need more places like this in the world, to counter all the ignorance-is-bliss-and-science-is-suspect Neanderthals out there. So this is my love letter to the Exploratorium, and every other science museum laboring to bring the light of knowledge to the masses. Your efforts are appreciated.”

Yay! Thanks Jennifer! Not that I can take much of the credit…

Hey baseball fans — the all-star game was just last week in San Francisco, so the Exploratorium did a whole bunch on the science of baseball. Fun stuff. How does a curveball work, and what makes a sinker? Here are some links:

KQED Quest show on baseball (about 20 minutes) including our Teacher Institute director Linda Shore and senior graphic artist Dave Barker. A really nice show. A segment of this show was aired on News Hour with Jim Lehrer!

The front page of the San Francisco Chronicle showed our staff member Sebastian Martin throwing a baseball “like a European.” Well, he is German… Some interesting stuff about physics in there too.

Iron Science Teacher show on baseball. Our live webcast featuring a secret ingredient… last week was baseball! This is the first time a member of the audience has won the contest! Amazing kid…

My podcast Science Teaching Tips won an award a week or so ago, for Best Professional Development podcast, through the Podcast for Teachers. They just posted a very nice interview with me, which I included in a new post on Science Teaching Tips. I talk about why I started the podcast, and why I think it can be a great venue for professional development for teachers. Listen to the interview here.

I love this little activity… Have an old record but no record player? Here’s how you can listen to it. Take a record and stick a pencil through the hole in the middle so it’s pretty close to the point of the pencil. That’s your turntable. Now take a piece of paper and roll it up into a loose cone and tape it. Flatten the pointy end a little and stick a pin through it. You may want to tape the pin to the end of the paper cone so it’s more stable. Now have a friend turn the record by slowly rotating the pencil. Place the pin, point down, on the groove of the record, and gently hold the cone so the pin stays in the groove of the record. Try to turn it at 33 1/3 times per minute — good luck! Here is a more detailed description of the activity.

Here is my post on my podcast where you can hear how it sounds and how to teach it.

You should hear the music playing, albeit a bit wobbly. The record has a groove in it — one long spiral. The needle vibrates in response to the shape of the groove. But the needle on its own doesn’t vibrate very much air. When it’s attached to the cone, it vibrates the cone, which can then vibrate more air, making the sound louder. The cone also directs the sound, making it easier to hear.

Today’s students often haven’t seen a record before, and so it can be useful to look at it under a microscope or magnifying glass to see the groove. Note that a CD is also sort of “carved” — it has microscopic pits in it. But instead of mechanical vibrations, the grooves in the CD are so tiny that it interacts with light. That’s why records wear out — the needle wears out the grooves. That’s not a problem with CD’s, since it’s just light touching the surface. Interestingly, it doesn’t matter (as much) if you scratch the side of the CD with the rainbows on it — but if you scratch the metal coating on the other side, the light won’t reflect from it correctly and you’ll spoil the CD.

Wikipedia has more information on phonographs, and so does this site from Arbor Scientific.

If you’re interested in making your own working phonograph (not just the pin and paper method) to actually record your voice using a plastic cup (replacing the old fashioned wax cylinder), check out this kit from Make Magazine. I hear they don’t carry the kit anymore, but someone Googled and found it by a company in Japan.

Here’s a video of it in action and here’s what it sounds like.

A teacher on a teacher listserv I’m on writes:

In my collection of Edison Phonographs I have many that will allow for purely mechanical reproduction of sound. I have an Edison tinfoil phonograph that records on tinfoil (duh) and numerous machines that record on wax cylinders. First the wax cylinder is shaved to a clean surface then a cutter head consisting of a diaphragm with a sapphire cutting stylus is lowered onto the record surface. As the cylinder turns, wax is cut by the stylus where the depth of the cut represents the wave pushing/pulling on the diaphragm. It is called the “hill and dale” or vertical cut type of recording.

The Gakken phonograph made in Japan uses a side by side motion or lateral recording. This is what the common 78 RPM records used from 1896 up through the mid-1950s. The toy phonograph does work but results vary depending on numerous factors. One is the temperature of the plastic cup used for the recording. I have found that a hair dryer warming the cup helps but one must be careful not to melt anything. The Gakken machine appears on eBay regularly under the search Edison Phonograph but shipping is as expensive as the machine is because it is air mailed from Japan. Maker Shed in the US carries it as well with some savings on postage but at a higher price.