Dan Russell (Dr. Batman)

YouTube video by Dan Russell ACS 502 Sound Waves In Fluids Fall 2025 at Penn State

Time for another fun movie trailer to entice interest in the first-year graduate course in Acoustics that I'll be teaching for the Graduate Program in Acoustics at Penn State in the Fall 2025 semester. Simultaneously offered online through our distance education program!
youtu.be/fKPA5HL76Ps?...

photo of Dan Russell (white male, approximately 30 years old, blond hair and glasses, wearing a red shirt) sitting to the right of a computer monitor.

photo of Dan Russell (white male, approximately 55 years old, gray hair, beard, and glasses, wearing a checkered shirt) standing to the left of a computer monitor.

30 years of making animations . . . I'm updating HTML code for my Acoustics and Vibration Animations website (for WCAG accessibility and HTML5) and found an archive of my original website from 25 years ago with a photo of me in my office at Kettering University.
www.acs.psu.edu/drussell/demos.html

Yessir.

Thanks! I learned that technique from Tom Rossing in 1990 while I was working on my MS with him.

Brand new video demonstration . . . Standing Waves inside a Cylindrical Cavity. Finding nodal surfaces for acoustic standing wave mode shapes inside a cylinder with "rigid" walls -- a plastic CD container. #iteachphysics #acoustics

youtu.be/-4IqtGhWe2U?... via @YouTube

Except that this thesis explored computer models of hollow aluminum bats that were rigidly clamped at the handle which is completely wrong. So the results of her models are pretty much useless for predicting handle vibration in actual bats or sweet spot location.

The Physics of the Torpedo Bat What can physics tell us about the torpedo bats?

Really good preliminary summary of what we know so far about torpedo bats by my fellow bat researcher @pobguy.bsky.social
blogs.fangraphs.com/the-physics-...

My favorite way to spend a quiet Sunday evening.

How can a person with “zero education” ever learn to ask the right questions? Education in the relevant field is what helps you know the right questions to ask.

Don’t know. I’m a non-tenure track teaching faculty so I don’t have overhead return.
Turns out the architect firm demanded the doors be replace and the contracted supplied is eating the cost. Still seems like an awful waste to me. Doors are going to be discarded to trash.

Photo of my wood office door

Close up of my office door showing the ugly wood knots that require the door to be replaced.

What a stupid waste of money. @PSUEngineering is replacing many dozens of doors in our 6 month old new building because the wood veneer on some doors has some unsightly wood knots. Here’s my office door (with ugly knots) that is slated for replacement. What a stupid waste of $$.

Where did you get that amazing birdfeeder pole?

📌

So during a 5-minute "lightning round" #ASA187 session this morning, I complained that someone else's 5-minute talk lasted 12 minutes.

Well, this afternoon I contributed to a 5-minute lightning round session.

Any guesses as to how long my own "5-minute" talk lasted? 🤦‍♂️🤦‍♀️🤦

Thank you for letting me know you find them useful!

Listening to the keynote address for #ASA187 . . . humorous inverse correlation => larger larynx (deeper + louder vocal production) in howler monkeys correlates to smaller testicles. Bigger balls means less powerful and higher sounding howl.

It is a great app! I use it with my undergrad acoustics course - mostly because it looks and behaves the same on both iOS and Android devices. There are some things I wish it did better, but overall I have gotten a fair amount of use out of it. Simple and functional is good.

YouTube video by Dan Russell Speed of Sound Depends on Air Temperature

Audio/Video demonstration of an "acoustic thermometer" => how the speed of sound changes with temperature — observed as a change in the resonance frequency of a short closed-open pipe.
youtu.be/9Pmsn_JZU-4

#iTeachPhysics

During the current migration to 🦋 I have gained lots of new #iTeachPhysics follows including many people I don’t recognize from X. I currently teach grad level acoustics but my waves and vibration animations website is useful for HS and undergrads students:
www.acs.psu.edu/drussell/demos.html

oops -- I'm still getting used to the tags on this platform. Thanks for replying and adding those tags.

just heard a cool presentation at the ASA 187 Virtual Meeting . . . taking each element in the periodic table and creating an audible sound based on the atomic emission/absorption spectrum for that element.
academics.skidmore.edu/blogs/jlinz/

Wave speed on a slinky depends on the number of coils.

Part of the confusion is that what we call acoustic (mass-spring) “particles” aren’t molecules. An acoustic “particle” is a volume small enough (compared to wavelength) that acoustic variables are constant throughout but containing enough molecules (>20,000?) so that continuum model is valid.

I’m here (just don’t check in often). Question from a non-Brit American bloke across the pond (who often uses the same words but with different meanings): what does “modulus” mean to you in this context? I really like the question—but I don’t think I’m interpreting “modulus” as you intend.

I use a mass-spring model for longitudinal waves in solids because wave speed depends on elasticity (stiffness) and inertia (density) of the material. Same is true for air. Mass-spring shows the progression of a wave so students can understand. What would you suggest using instead?

2/2 . . . that I no need or don't use. I put the books outside my office in the hallway emailed all of our grad students to tell them a bunch of books were available. Within 5 minutes, this was the scene outside my office door! Hopefully most of these books can find a new home.

1/2 Next year my graduate program is moving into a new building (currently under construction). My office will be smaller and I've been told I have to downsize from 4 completely full bookshelves to 2 (yikes!). So, I made a first pass thru my office library to identify books . . .

Went through some of my parents’ photos after dad died last year and found this autographed photo of Tenzig Norgay (2nd person to the top of Mt Everest in 1953 behind Sir Edmund Hillary). I got this photo as a kid in Hong Kong in 1976 but thought it was lost years ago.

Wonder if it’s worth any $$?