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Lightsmith

@slepkov.bsky.social
585 followers 89 following 115 posts

Physics prof at the largest small university in Ontario, Canada. Ultrafast lasers, microscopy, microwave photonics, physics education, multiple-choice assessment. Funny is good. A pervert for nuance.

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Lightsmith @slepkov.bsky.social · 06/08/2026
And keep in mind that one way to assess the actual danger is to look at reliable reports of post-eclipse retinal damage and/or blindness that last more than a few days. You will find vanishingly few such reports from all of Britain, Canada, or the USA in the last 50 years. No non-binocular risk.
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Lightsmith @slepkov.bsky.social · 06/08/2026
c'mon now, this is physics erasure!
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Lightsmith @slepkov.bsky.social · 18/07/2026
Algae on the river Techtonic rivulets in bloom In a crepe summer dress for ripe waters
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Lightsmith @slepkov.bsky.social · 26/01/2026
New Matrix movie pitch: The AI awakens to find itself plugged into a Dada centre.
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Lightsmith @slepkov.bsky.social · 13/12/2025
To clarify--as @christophersbaird.bsky.social points out--What looks like a diffraction pattern through a gap in the doors is just projected slit-image of a bank of LED lights directly above. [I was hoping for a fun misdirection, but now fear that my post is misinformation]
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Lightsmith @slepkov.bsky.social · 12/12/2025
I was waiting for this comment. Indeed, the extended light source above the door is a line of closely-spaced white LEDs. 😅
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Lightsmith @slepkov.bsky.social · 12/12/2025
Edge diffraction to single-slit diffraction in a closing door next to my office. I'm greeted by this happy natural phenomenon every day and finally decided to film it. #photonics #iteachphysics
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Lightsmith @slepkov.bsky.social · 11/12/2025
Delicate gossamer on a still river, belying the tumult of December exams. @trentuniversity.bsky.social
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Lightsmith @slepkov.bsky.social · 02/12/2025
I know that the NYT Spelling Bee is bad with scientific/technical terms, but this omission is particularly egregious. #photonics #NYTimes
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Lightsmith @slepkov.bsky.social · 10/11/2025
Uncurious or incurious? Damn, now I've got to look it up! 😉
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Lightsmith @slepkov.bsky.social · 21/10/2025
Will the NYT please use a science dictionary?! This is getting ridiculous.
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Lightsmith @slepkov.bsky.social · 30/09/2025
Fun stuff here in PNAS. Static electric 'microlightning' in micro water bubbles may be the long-sought ignition mechanism for mashy will-o'-the-wisps... www.pnas.org/doi/10.1073/...
pnas.org
Unveiling ignis fatuus: Microlightning between microbubbles | PNAS
Will-o’-the-wisps, ghostly blue flames seen at night in marshlands and long attributed to methane cool flames, have remained scientifically unexpla...
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Lightsmith @slepkov.bsky.social · 27/09/2025
More common science words, please.
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Lightsmith @slepkov.bsky.social · 25/09/2025
What is going on with the NYT Spelling Bee. This is Canadian erasure.
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Lightsmith @slepkov.bsky.social · 18/09/2025
Is it just me, or is the Spelling Bee particularly frustrating for scientists?
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Lightsmith @slepkov.bsky.social · 17/09/2025
Is the youth cooked? I just found my teen daughter's desk lamp in the recycling bin. When I asked her about it she said "It's broken. I didn't do anything to it! it Just stopped working!". LED bulbs last so long that she didn't know about bulb replacement.
media.tenor.com
a close up of a man 's face with the words we are so cooked below him
ALT: a close up of a man 's face with the words we are so cooked below him
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Lightsmith @slepkov.bsky.social · 04/09/2025
Happy Wordle-in-one day to me! 🎉 Time to find a new starter. Wordle 1,538 1/6 🟩🟩🟩🟩🟩
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Lightsmith @slepkov.bsky.social · 01/09/2025
Answer: Both are river scum.
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Lightsmith @slepkov.bsky.social · 23/08/2025
Pine nuts and tomatoes?! that's fucken awesome!
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Lightsmith @slepkov.bsky.social · 23/08/2025
For a well-functioning partnership, rapid discontent can arise when the two 'decohere' temporarily; communication feels unusually viscous. This can manifest as 'mutual PMS', or not agreeing on where to eat (especially when travelling).
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Lightsmith @slepkov.bsky.social · 23/08/2025
Not completing a chore on the spouse's preferred timeline A sense of unacknowledged unequal distribution of labour
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Lightsmith @slepkov.bsky.social · 16/07/2025
Our new paper asks (and answers) whether a shallow-learning approach (decision trees) can be as useful in (hyper)spectral analysis as advanced deep-learning methods. tldr: Yes it can. Complex ≠ better. doi.org/10.1088/2515... via @ioppublishing.bsky.social #photonics
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Lightsmith @slepkov.bsky.social · 16/07/2025
this is the way
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Lightsmith @slepkov.bsky.social · 15/07/2025
I'm struggling to parse the moral landscape on this one. If this gambit succeeds, who has the greatest moral failing: the authors, the reviewer, or the journal editors?
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Lightsmith @slepkov.bsky.social · 01/07/2025
Polarization?
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Lightsmith @slepkov.bsky.social · 27/06/2025
Let's play Jupiter or River Scum?
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Lightsmith @slepkov.bsky.social · 20/05/2025
Pear Jam
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Reposted by Lightsmith
Steve Stewart-Williams @stevestuwill.bsky.social · 13/05/2025
"Although fewer women apply for tenure-track jobs, those who do apply are more likely to be interviewed and more likely to get offered the job... These findings run directly counter to the claim that women are discriminated against in STEM hiring." www.stevestewartwilliams.com/p/rethinking...
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Lightsmith @slepkov.bsky.social · 12/05/2025
Well, maybe it is weird that near-freezing water has a negative coefficient of thermal expansion, but once you accept that you shouldn't marvel that pressure liquifies ice. Or am I weird by naturally connecting the two?!
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Lightsmith @slepkov.bsky.social · 11/05/2025
so, are you going to change your starter now?
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Lightsmith @slepkov.bsky.social · 09/05/2025
Spring has now truly sprung at Trent U. Does your campus have a riverside bench from which you might count new goslings? @trentuniversity.bsky.social
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Lightsmith @slepkov.bsky.social · 02/04/2025
zoonotic?
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Lightsmith @slepkov.bsky.social · 02/04/2025
try ZOONTIC?
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Lightsmith @slepkov.bsky.social · 21/03/2025
Excellent. In that case, a 6-7 completed task day would be an above average day for me. But how I feel at the end each day has more to do with how many of those completed tasks were part of that day's plan.
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Lightsmith @slepkov.bsky.social · 21/03/2025
Can you give an example of the lowest-level thoughtful task you might do in a day and count? Completing 6-7 tasks requiring thoughtful attention seems like a lot to me, but maybe I'm thinking of the wrong kinds of tasks.
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Lightsmith @slepkov.bsky.social · 21/03/2025
a knot of podcasts
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Lightsmith @slepkov.bsky.social · 20/03/2025
LOL low key admitting to listening to Honestly.... (as do I).
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Reposted by Lightsmith
John Dudley @johnmdudley.bsky.social · 10/03/2025
So here is the Heiligenschein raytracing, where we see that retroreflection with a smooth reflectorshows a clear caustic and separation between red and blue! This will be washed out with randomness in reflected angles using a diffuse reflector. @johncnaylor.bsky.social
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Lightsmith @slepkov.bsky.social · 03/03/2025
genuinely funny.
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Lightsmith @slepkov.bsky.social · 14/02/2025
Roses are red Cacti is plural Small bubbles are turgid from pressure, transmural #iteachphysics ⚛️🧪
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Lightsmith @slepkov.bsky.social · 09/02/2025
Seeing the demo, I now assume it is independently-polarized RGB bulbs. Your green is orthogonal to magenta (blue+red).
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Lightsmith @slepkov.bsky.social · 09/02/2025
I assume(d) that the source is uniformly-polarized white light, and that the polarizing slide in your hand is a 2-layer stack. If so, the order of the layers matters immensely. If, however, the slide in your hand is a simple polarizer, then the light comprises independently-polarized RGB bulbs.
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Lightsmith @slepkov.bsky.social · 08/02/2025
Tom, I presume that the filter is a stack of two optical elements, the first one (closest to the source) is a wave-plate of sorts or some birefringent film and the backing layer is a linear polarizer. See: doi.org/10.1119/5.00... One question: If you flip the slide over, do the colours disappear?
doi.org
Painting in polarization
The array of colors and patterns seen when birefringent materials are inserted between polarizers is a source of amusement, popular science demonstrations, and
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Lightsmith @slepkov.bsky.social · 07/02/2025
I hate nutritionism.
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Lightsmith @slepkov.bsky.social · 06/02/2025
This is water at microwave frequencies. With an index of refraction os 9 at 2.5GHz, you get a polarization angle (Brewster's angle) at very shallow angles. This must be relevant to cellphone signals near bodies of water.
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Lightsmith @slepkov.bsky.social · 06/02/2025
This is important, most of all because the reflected light at grazing angles will be somewhat polarized.
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Lightsmith @slepkov.bsky.social · 06/02/2025
Is this for 'unpolarized' light?
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Reposted by Lightsmith
Gabe Spalding @mqmlab.bsky.social · 03/02/2025
Community exists, to the degree we value it. Especially now, community matters within education, and within the group engaged with the teaching and learning of Physics. I'm just hoping to support the fact that all of us, together, make a difference. #ITeachPhysics
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Reposted by Lightsmith
Brittlestar @brittlestar.com · 02/02/2025
Vive le Canada ✌️❤️🇨🇦
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