Determine Fundamental Constants with LEDs and a Multimeter
There are (probably) less than two dozen fundemental constants that define the physics of our universe. Determining the value of them might seem like the sort of thing for large, well funded University labs, but many can be determined to reasonable accuracy on the benchtop, as [Marb’s Lab] proves with this experiment to find the value of Planck’s Constant.
[Marv’s Lab] setup is on a nice PCB that uses a rotary switch to select between 5 LEDs of different wavelengths, with banana plugs for the multi-meter so he can perform a linear regression on the relation between energy and frequency to find the constant. He’s also thoughtfully put connectors in place for current measurement, so the volt-current relationship of the LEDs can be characterized in a second experiment. Overall, this is a piece of kit that would not be out of place in any high school or undergraduate physics lab.
To use this to determine Planck’s constant, you need to use Planck’s relation for the energy of a photon:
E = hf
Get some Energies (E), get some energies (f), and bam! You can generate a value for h, Planck’s constant. The energies? Well, that’s a very easy measurement, but it requires some understanding of how LEDs work. [Marb] is simply measuring the voltage needed to just barely light the LED of a given frequency. (For frequency, he’s relying on the LED datasheets.) That translates to the energy of the photon because it corresponds to the energy (in electron volts) required to jump electrons over the bandgap of the semiconductor in the LED– that’s how the light is generated. Those photons will have the energy of the gap, in theory.
In practice, the LEDs do not emit perfectly monochromatic light; there’s a normal distribution centered on the color they’re “supposed” to be, but it is fairly tight. That’s probably why is able to [Marv] get to within 5% of the canonical value, which is better than we’d expect.
This isn’t the first time we’ve determined plank’s constant; it’s quite possible to get to much higher accuracy. The last time we featured this particular technique, the error was 11%.
youtube.com/embed/P9X2qtBVRxA?…
Passer domesticus
#animal #animais #animals #fotografias #photo #photograph #photos #birdwatching #birding #santamaria #santamariars #riograndedosul #bird #birds #Ave #aves #asavesqueeuencontro #patricianicoloso
State-backed Huaneng Group has launched 100 autonomous electric mining trucks in Inner Mongolia, the largest single deployment of its kind.
Equipped with Huawei’s AI, 5G-A, and smart battery-swapping tech, the "Huaneng Ruichi" trucks boost transport efficiency by 20% and slash costs. Plans call for 300 trucks by 2026, highlighting China’s push to digitize heavy industry already cutting mining costs by 8%.
scmp.com/tech/big-tech/article…
China deploys world’s largest fleet of driverless mining trucks, powered by Huawei tech
The project aligns with the nation’s broader push to upgrade traditional industries with AI and other advanced technologies.Ben Jiang (South China Morning Post)
If you’ve been thinking about subscribing to my Substack, now’s a great time to jump in. It’s free (unless you want access to the archive), and I post at least twice a week—sometimes more. Short stories, essays, poetry, and whatever else I can’t help writing.
Something special lands Tuesday morning: a new science fiction piece in the classic tradition. Would love to have you there.
Healthy Word Salad | Rob Archer | Substack
stories - essays - poetry. Click to read Healthy Word Salad, by Rob Archer, a Substack publication. Launched 2 years ago.Healthy Word Salad
dr.dk/sporten/ishockey/landsho…
Landsholdet kunne ikke have drømt om mere
Sejren over Norge betyder, at danskerne med en sejr i den sidste gruppekamp kan spille sig videre til kvartfinalen.DR
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Must read from our Palestine newsroom: Israel just launched its offensive to permanently ‘conquer’ Gaza as Trump’s Arab Gulf tour wraps up
Israel announced the initial phase of “Gideon’s chariots,” the expanded ground invasion to permanently “conquer” Gaza, amid reports that Trump reneged on his deal with Hamas to lift the blockade, and will reportedly expel 1 million Gazans to Libya.
AIお任せでプログラム開発。ChatGPTの新機能「Codex」を試してみた
unicornriot.ninja/2025/the-202…
The 2025 Romanian Presidential Election This Sunday Could Change The Fate of Europe - UNICORN RIOT
The presidential elections are happening again in Romania, after the regular electoral cycle was annulled. The scourge of simmering hatred, bigotry and anti-democratic sentiments he gave voice to are now openly disseminated.D (UNICORN RIOT)
China deploys world’s biggest fleet of driverless mining trucks
China deploys world’s largest fleet of driverless mining trucks, powered by Huawei tech
The project aligns with the nation’s broader push to upgrade traditional industries with AI and other advanced technologies.Ben Jiang (South China Morning Post)
Well that's a relief. Bet there will be a huge investigation into this voting round this year. In a week when at least another 300 people in Gaza have been killed.
And can we agree that until Israel stops the war they are suspended from #Eurovision now...
dr.dk/nyheder/udland/israel-be…
Israel begynder kraftigt kritiseret offensiv i Gaza
Efter at have blokeret al nødhjælp og forsyninger i over to måneder er situationen i Gaza allerede katastrofal. Nu bekræfter Israel, at militæret har påbegyndt en ny offensiv.DR
Eurovision 2024 Results: Voting & Points
Eurovision 2024 results: All the voting and points from the Eurovision Song Contest 2024 in Malmö. Switzerland won with the song "The Code" by Nemo with 591 pointsEurovisionworld
Si los bots del Mossad este año se llevan el gato al agua, igual Eurovisión 2026 es el último festival de todos.
eldiario.es/vertele/noticias/g…
El Gobierno de Israel confirma que invirtió mucho dinero para fomentar el voto a Eden Golan en Eurovisión 2024
Un alto cargo del Ministerio de Asuntos Exteriores israelí admite que el alto televoto recibido por Eden Golan en la final del festival estuvo precedido de una importante campaña promovida por ellos: "Intervinimos entre el público que nos simpatizaba…Laura Pérez (Vertele)
Centri estivi nella Piana di Lucca: nasce l’elenco zonale delle attività accessibili a tutti i bambini
Al Centro famiglie di San Concordio l'open day con l'obiettivo di una maggiore inclusione. Presto l'avviso per i voucher
Popemobile converted into clinic for Gaza’s wounded children
More than a decade after it carried the late pope through the streets of Bethlehem during his 2014 visit, the white Mitsubishi pickup is being repurposed to deliver life-saving care to some of Gaza’s most vulnerable.
The decision was one of Francis’s final wishes before his death on April 28, according to the Vatican News and confirmed by The New York Times.
@palestine
#WestBank
#Bethlehem
#Gaza
#PopeFrancis
#Journal of a slightly exhausted Dutch Pixy 
(Saturday 17/05/2025).
I woke up when my alarm told me it was time. Gave Arwen her meds and got to the scale. Which was kind enough, seeing the circumstances... I got dressed and took Arwen out to do her things. I took my own meds and spent some time online. A very sweet friend had gotten some awesome good news, so I was super excited for them! 
Then, it was time to feed Arwen and get ready to head to the gym.
I enjoyed my protein shake while I checked my socials some more. Then, I rode the seated bike for a while, followed by 1km on the treadmill. A massage in the chair, before I got ready to head back home again.
I washed up, changed clothes, and had brekky. When I wanted to walk the SniffiVerse™ walkies with Arwen, she was having some issues with one of her paws. There was a little sore spot between two of her pads. So we walked a very short walk, and when we got home, I did my best to clean it and get ointment on it. Arwen didn't like it, but hopefully she noticed that it did help her...
I went upstairs and wanted to work on my blog. A four minute update was needed. Well, yes, the update took 4 minutes.... Then another 31 before the PC was ready to be used again... 😔 I spend some time rowing, and when I got to the home trainer, after a few minutes, the PC was ready. Finally! So I could finally finish the blog bits and then go downstairs. I wanted to relax a bit. But seeing the time, I had to fix some food...
Walked a short round with Arwen after that. Then, I got my garden stuff and I tried to make some more progress in the front garden. While I was busy, the neighbor and her dog came by. Arwen wasn't too amused when we didn't join them... After about an hour, I was tired, aching, and sweaty all over! So I cleaned up the tools and I got a shower.
The washing machine started after that. Some relaxing while it was doing its thing. Then, after I'd hung the laundry, we headed out for walkies again. Arwen was fortunate, as we did see N&B again. We had a nice walk and I told N that we could not make the afternoon walkies due to the garage visit later.
When we got back, I relaxed a wee bit in the garden with my eBook. Then, when it was time to head to Nijmegen, Arwen and I got to Skoosh. When we got there, I took the dogs to the small woods. By the time that we got back, mum was home too and dad was getting ready to head to the garage.
I'd told him about the highway part being closed. So, of course, he drove his usual way to the garage, to find out that, heck! The highway was closed! 🤦🏼♂️ Ugh... Yeah... Who knew eej? So when we finally got there, the guy my dad had the appointment with, was busy... And so the wait began. The folks he was helping were making an outing of it... They took ages! Dad and I were able to take the "new" car for a test drive. And dad was pleased... Then, we waited some more...
I started browsing all the cars they had there and I found the keys in one of them! Euh, I don't think they should be in there?? 🤔 So when the sales man finally had time for us and everything was discussed... I told him about the keys. And he was grateful for my telling him, as it indeed was an insurance nightmare, should something happen! So, me waiting and checking out all the cars, it did have a positive side. 😂
My parents got a loan car from the garage, to use until the "new" car would be ready for them. It was a C-HR. I'd never driven one of those. 😇 Dad had to take the rental to the rental place, and then I offered to drive them back in the C-HR, as I had just adjusted everything anyway. (plus it meant that I could drive...).
I got my parents home safe and sound. Then, I took Arwen home with me. A short walk with her before bed time. I was soooo tired! Usually I go to bed around 15:30, and it was almost 17:30 now. It was gonna be a short night.
After a short while, I fell asleep. When the alarm woke me up, and I wanted to give Arwen her meds, I saw and smelled... A brown prezzie from Arwen to me. So, even with the door open, she didn't come to get me when she needed me... 😔
So she got her meds and we rushed outside. And then, I started my day/night with cleaning... Yay...
🍀 💜 🐾
#PixysJourney
#WeirdFolks
@weirdfolks
The image depicts a serene landscape at sunset. The sky is a gradient of colors, transitioning from a soft blue at the top to warm hues of pink and orange near the horizon, where the sun is partially visible. Wispy clouds are scattered across the sky, reflecting the sunset's colors. In the foreground, a dense cluster of trees with dark green foliage frames the scene, their silhouettes contrasting against the colorful sky. The trees appear to be in a natural setting, possibly a forest or a park, with a field of grass visible at the bottom of the image. The overall atmosphere is tranquil and picturesque, capturing the beauty of nature during the golden hour.
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Not bad JJ, not bad at all. The winner of the Eurovision 2025 is: JJ from Austria.
#Eurovision #JJ #Austria
Cedar Rock State Park
Quasqueton, Iowa, USA; traditional territory of the oθaakiiwaki‧hina‧ki (Sauk) & Meškwahki·aša·hina (Fox), Báxoje Máyaⁿ (Ioway), and Očhéthi Šakówiŋ nations / Explore more at bit.ly/CedarRock_2023-10-01
#photography #travel #Iowa #IowaStateParks #FrankLloydWright #architecture
Cedar Rock
“Early in life I had to choose . . .” … between honest arrogance and hypocritical humility. I chose honest arrogance and have seen no occasion to change.” ~ Frank Lloyd WrightSouthern Minnesota Guy
📒 Assemblea Pubblica per la Palestina
🏷️ assemblea, palestina
📅 giovedì 22/05/2025 h18:00
🌍 La Base Cosenza
📍 Via Macallè 17, 87100 Cosenza, CS
🔗 camifa.net/event/assemblea-pub…
#art #humanartist #landscapeart #madewithkrita #krita #MastoArt
You can discover what your enemy fears most by observing the means he uses to frighten you.
-- Eric Hoffer
⬆ #Wisdom #Quotes #EricHoffer #Fear
⬇ #Photography #Panorama #ChacoCanyon #Panopainting #NewMexico
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Thanks to @futurebird I notice ant news like I have an alert.
abc.net.au/news/2025-05-18/aus…
ABC News
ABC News provides the latest news and headlines in Australia and around the world.Gavin McGrath (Australian Broadcasting Corporation)
Art installation on National Mall shares trans voices of hope, defiance
https://www.washingtonpost.com/dc-md-va/2025/05/17/freedom-to-be-trans-quilt-aclu/?utm_source=flipboard&utm_medium=activitypub
Posted into Local @local-WashPost
iclcit.org/urgent-call-support…
(Spanish)
iclcit.org/es/urgente-apoyo-a-…
Federation of General Workers Myanmar
fgwm-solidarity.org/
#Burma #Myanmar #labormovement #organize #solidarity #unions #FGWM #FAU
Urgente: apoyo a Myanmar tras el devastador terremoto
Junto a nuestra organización amiga Federation of General Workers Myanmar (FGWM), venimos coordinando una serie de acciones internacionales para ejercerICL CIT (International Confederation of Labor)
Nuta, a corresponding member of the #IdąPsięta pack, hoping to break free and ride one of those horses.
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"Custodire l’ambiente, proteggendo la famiglia" con Vannacci
"Custodire l’ambiente, proteggendo la famiglia": arriva a Lucca l’evento promosso da Pro Vita & Famiglia Onlus nell’ambito del ciclo "Vivi...
lanazione.it/lucca/cronaca/cus…
"Custodire l’ambiente, proteggendo la famiglia" con Vannacci
"Custodire l’ambiente, proteggendo la famiglia": arriva a Lucca l’evento promosso da Pro Vita & Famiglia Onlus nell’ambito del ciclo "Vivi...FABRIZIO VINCENTI (La Nazione)
How to achieve a lasting ceasefire between Russia and Ukraine?
https://www.aljazeera.com/video/inside-story/2025/5/17/how-to-achieve-a-lasting-ceasefire-between-russia-and-ukraine?utm_source=flipboard&utm_medium=activitypub
Posted into Europe News @europe-news-AlJazeera
How to achieve a lasting ceasefire between Russia and Ukraine?
A Russian drone strike hit Ukraine’s Sumy region hours after first direct talks in three years.Al Jazeera
Altbot
in reply to Dan Sloane • • •The image shows a screen displaying the "UK Audience Vote" results for a competition, likely a music contest. The list is ranked from 1 to 12, with Malta in first place, Israel in twelfth place, and the other countries in between. The countries listed are Malta, Greece, Latvia, Finland, Albania, Estonia, Sweden, Lithuania, Poland, and Israel. The background of the screen is dark, with the text and numbers in bright colors, making them stand out. On the right side of the image, there is a person wearing a black shirt with silver embellishments, holding their head with both hands, possibly in a moment of emotion or reaction to the results. The person is wearing a bracelet on their left wrist. The overall atmosphere suggests a significant moment in the event, possibly a reaction to the audience's voting results.
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