Sunday, July 27, 2014

My AAPT SM14 photo album begins

Most images are from Sunday's High School Share-a-thon at The American Association of Physics Teachers Summer Meeting 2014 (AAPT SM14) so far.

Monday, July 14, 2014

Yellowstone lightning strike caught on video

The lightning grounded through a tree and the voltage remained high through the conductive root structure. The heating of the surrounding (less conductive) earth was rapid and intense, resulting in what look like explosive pop of soil.

Click to link to the video

Enjoy the curious stat about lightning strike "gender bias".

Friday, July 04, 2014

I was bound to do this

So there I was at Victoria Falls, on the border between Zimbabwe and Zambia. The Victoria Falls Bridge spans a gorge through which the Zambezi river runs, post falls. We are told the deck of the bridge is 135 meters above the water.

At the midpoint of the bridge there is a low-slung hut through which bungee jumpers are fitted with harnesses and pushed over a precipice. We are told the bungee jumpers plummet 111 meters, though it seems the mileage would vary from one jumper to the next, depending on weight.

I'm much too bashful to reveal my weight, but the bungee operators wrote 111 on my arm after having me stand on a scale. Oh yeah, I signed up for this jump. I teach physics! I was bound to do this.

They harness you quite thoroughly, and cinch your lower calves to each other and attach them to the bungee cord with five carabiners. I was bound to do this.

They help you waddle out over the lip of the diving platform. Then it's "5-4-3-2-1-BUNGEE!" and off you go, into the gorge. But enough jibber-jabber. Let's roll the film.

Victoria Phyz Falls

Was I ever really in danger? As it turns out, yes I was. This very jump dropped an Australian woman into the Zambezi a few years back.

Aussie Tourist's Bungee Cord Snaps

I really only put myself at risk like this so that Dan Burns could generate some nice, personalized physics problems, if he is so inclined. If you think of some, leave them in the comments or email them to me.

Did I mention that I jumped off a bridge?

My African media shoeboxes

The month-long African safari is in progress!

Lightly-processed safari photos are accumulating on Flickr:

Accommodations and other random shots are accumulating here:

Videos are accumulating here:

The blog at Outdoor Safari Photographers. I was/am with them June 16-20 (Machaba), June 28-July 2 (Chobe/Pangolin), and July 5-9 (Elephant Plains).

Further details when I return.

Saturday, June 14, 2014


Jolly? Sometimes. Good? Depends on who you ask.

Fellow. Most indubitably.

At least I will be, as of the American Association of Physics Teachers (AAPT) Summer Meeting 2015.

More details will no doubt emerge at the meeting. But it appears that AAPT is assembling a cadre of honored individuals and bestowing the title of "Fellow" upon them. The AAPT honored me in 2008 with their Distinguished Service Citation. And as I continue to be a member in good standing, I have been included in the first cohort of this cadre.

There will be some manner of shindig exclusive to AAPT Fellows at the Summer Meeting, and we are invited to add the honorific of "F.AAPT" or Fellow, AAPT" after our names on correspondence.

In any case, it's a delightful honor and I am humbled to be in such austere company.

Dean Baird

Monday, June 09, 2014

Tower of paper

Our end-of-year schedule included an amusing burp this year. It came on the last Thursday of the year. Students in periods 1-4 had already had their final exams on Tuesday and Wednesday, and students in periods 5 and 6 would have their final exam on Friday. All students in all classes met on Thursday.

What to do?

Give each lab group a single sheet of colored 8.5"x11" paper, a pair of scissors, and a table-width length of masking tape (about 2 feet), along with the directive to use those materials to construct a free-standing tower of maximum height.

Only the paper and the tape could comprise the tower (not the scissors). The tower has to stand for 5 seconds while its height (from the table top) was measured. The tower had to stand freely on the table (not taped down; not suspended from the ceiling or dropped outlets). Each group is given a distinct color of paper, no two are the same. (This helps with the integrity.)

One point of extra credit was to be awarded for every full inch of the tower's vertical height.

Our tallest tower this year was 57 inches tall. (I conjoin two meterstick/yardsticks and sometimes need to stand on a chair to get the measurement. I also turn off the HVAC) In the past, I believe the tallest tower we've ever had was 63 inches. Not bad for a single sheet of letter paper.

The students tend to be motivated, and it was a great activity for an otherwise throwaway day. And it's photogenic.

2014 05 Tower

Saturday, May 31, 2014

Rio Phyz 2014: Class Portraits

Some with flash; some without. Some with teacher; some without. Some straight; some goofball. The whole set can be accessed via this Flickr Set:

2014 05 Rio Phyz Class Portraits

This one might make for an interesting caption contest.


For some reason, it's always 6th period...

Friday, May 30, 2014

ExploratoRio 2014 - The Video

Directed and produced by student videographer, Grant Webster. Laugh, cry, relive the memories!

ExploratoRio 2014

Sunday, May 25, 2014

Outdoor activities for oddball days

A request was made (via our PTSOS discussion group) for outdoor activities that might be fun during weird days that seem to crop up at the end of the school year.

The ever-resourceful Los Gatos physics teacher and PTSOS leader, Dan Burns, suggested the following.

I like stomp rockets. Measure the distance to the launch, the angle it makes at apogee to the horizontal, calculate height. Measure time in air, calculate height and initial velocity.

Make pinhole cameras and use them to determine the diameter of the Sun.

Get in a line and spin in a circle. Each student calculates their angular and linear velocity.

Bang a drum twice per sec, students walk away until they hear the sound at the same time the drum is hit. Measure that distance, divide by 0.5 to get the speed of sound.

Make water balloon launchers out of surgical tubing. Calculate the force constant, the elastic potential stored, predict initial velocity and time in air if launched vertically. Then predict max range.

Have students push a car on a flat surface using bathroom scales. Drop beanbags at regular time intervals. Measure acceleration of car using the force applied and mass, compare to acceleration derived from pattern of beanbag separation.

Perform Herschel's experiment that detected IR radiation using glass prisms and thermometers.

Jump rope generator, rotate loop of wire like a big jumprope that is hooked to a galvanometer. See it generate current using earth's magnetic field. See Conceptual Physics Manual.