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
FreedomPatriot reshared this.
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.
Provided by @altbot, generated privately and locally using Ovis2-8B
🌱 Energy used: 0.165 Wh
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
- Sensitive content
- Parola filtrata: nsfw
- Sensitive content
- Parola filtrata: nsfw
- Sensitive content
- Parola filtrata: nsfw
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.
reshared this
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
A López Estelche's world premiere with Martínez and Schumann from Madrid - Schedule // - www.worldconcerthall.com
Sofía Martínez Villar, narrator, and the Spanish National Orchestra conducted by Ivan López Reynoso perform: Israel LÓPEZ ESTELCHE: Naturaleza muerta, world premiere. SCHUMANN: Symphony No. 4 in D minor op. 120. Recorded 1...www.worldconcerthall.com
Trump peddles false conspiracy theories tying Clintons to several deaths
https://www.washingtonpost.com/politics/2025/05/17/trump-clinton-false-conspiracy-theories/?utm_source=flipboard&utm_medium=activitypub
Posted into Politics @politics-WashPost
Putin-Zelensky Meeting Possible After Specific Agreements: Kremlin
A meeting between Zelensky and Putin is possible if certain agreements are reached by the delegations of the two countries, Kremlin spokesperson Dmitry Peskov said.Sputnik Africa
bbc.com/news/articles/cyvme1e8…
Police investigate explosion in Palm Springs, California
No one from a nearby fertility clinic was harmed, but one person was killed and several were injured.Nadine Yousif (BBC News)
From: @DJDarren
mendeddrum.org/@DJDarren/11452…
Darren (@DJDarren@mendeddrum.org)
Shocking that Israel should score so many points from the public vote... #EurovisionThe Mended Drum
Ein bunter Abend
mit Musik aus Europa
punktet in die Nacht
Kommt gut durch die Nacht und habt Dank für die Beiträge zum #esc
Coding without a laptop: Two weeks with AR glasses and Linux on Android
Link: holdtherobot.com/blog/2025/05/…
Discussion: news.ycombinator.com/item?id=4…
Coding Without a Laptop - Two Weeks with AR Glasses and Linux on Android
I recently learned something that blew my mind;holdtherobot.com
Cutting NWS will cost lives. The Jackson, KY office didn't have overnight forecasters for the storms that roll through last night. Overall, this meant the NWS was slower to respond to the storms in the area, so people got alerts/warnings later, which will lead to more injuries/deaths.
- reuters.com/world/us/bomb-expl…
College newspapers under pressure as immigration fears silence sources
https://www.washingtonpost.com/education/2025/05/17/college-newspapers-trump-international-students/?utm_source=flipboard&utm_medium=activitypub
Posted into Education @education-WashPost
In Texas, an early heat wave raises concerns for summer
https://www.npr.org/2025/05/17/nx-s1-5399613/in-texas-an-early-heat-wave-raises-concerns-for-summer?utm_source=flipboard&utm_medium=activitypub
Posted into All Things Considered @all-things-considered-npr
Kent Navalesi ☕️ reshared this.
oaklandside.org/2025/05/16/cra…
Cracking down on fare jumpers didn’t make BART safer or increase revenue, report finds
The Center for Policing Equity partnered with BART to produce a report that's skeptical of the agency's claims.Jose Fermoso (The Oaklandside)
Israel accused of ethnic cleansing after more than 140 killed in Gaza in 24 hours
Israel says intensified bombings are part of campaign expansion to ‘achieve all of the war goals in Gaza’
Boeier met vier figuren, Gerrit Groenewegen, 1791
etching, h 135mm × w 155mm
rijksmuseum.nl/en/collection/R…
#rijksmuseum #musea #collection #art #mastodonart #mastoart #random
Denmark fines two for desecrating Holy Quran
The men were found to have violated law banning “inappropriate treatment of a religious text”, which was implemented in 2023.AFP (DAWN.COM)
The video depicts a group of four characters, identified as "Lv.1 Cadets," sprinting across a desert landscape characterized by large, rock formations and a barren, sandy terrain. The cadets are wearing futuristic helmets and are seen running with urgency, kicking up dust as they move. The text overlay at the bottom of the frames reads, "The Lv.1 Cadets sprinting straight towards the hell bomb I just armed," indicating a sense of impending danger. As the cadets continue their run, the background shows large rock formations and a clear sky, with dust clouds visible, suggesting an explosion or disturbance in the distance. The cadets' determined expressions and forward-leaning postures emphasize their haste and the urgency of their mission. The video captures the cadets' relentless pursuit towards a significant threat, maintaining a consistent sense of urgency and danger throughout.
Provided by @altbot, generated privately and locally using Ovis2-8B
🌱 Energy used: 0.311 Wh
Stack Overflow Seeks Realignment 'To Support the Builders of the Future in an AI World' - Slashdot
"The world has changed," writes Stack Overflow's blog. "Fast. Artificial intelligence is reshaping how we build, learn, and solve problems.developers.slashdot.org
He is stupid. He is incompetent. He is cruel. He is sinister. And people will die because of what he’s done.
The image features a meme with a humorous take on the concept of "consensus." At the top, the text reads "THE MYTH OF 'CONSENSUAL'" with a small flag icon next to it. Below this, on the left side, there is a single figure labeled "Throwing a 500 Kilogram on the Pelican," depicted as a character in black and yellow armor with a cape. On the right side, there is a group of four identical figures, also in black and yellow armor, with the text "WAIT WAIT B3 WE'RE NOT IN YET." At the bottom, the text reads "ISN'T THERE SOMEBODY YOU FORGOT TO ASK?" The background is plain white, and the overall style is reminiscent of internet memes.
Provided by @altbot, generated privately and locally using Ovis2-8B
🌱 Energy used: 0.176 Wh
From CNN.com: At least 21 dead after tornado-spawning storms move across central US
@ai6yr Now up to 28 dead.
28 dead, half a million without power as deadly storms, tornadoes sweep across Central, Eastern US
A new round of severe weather turned deadly overnight Friday with multiple tornadoes tearing across the central United States, including one that prompted an urgent and rare tornado emergency in Illinois.
accuweather.com/en/severe-weat…
The video showcases a serene beach scene, focusing on a sandy shore with numerous footprints leading towards the water. The foreground prominently features the footprints, which are imprinted in the darker sand, contrasting with the lighter sand nearby. The beach is bordered by calm blue water on the left, with gentle waves lapping at the shore. In the background, a line of trees and a distant pier can be seen, adding depth to the scene. The sky is clear and blue, indicating a sunny day. The overall atmosphere is tranquil, with no visible people in the immediate vicinity, emphasizing the quietness of the beach. The camera remains stationary throughout, capturing the footprints and the beach's natural beauty without any movement or change in perspective.
Provided by @altbot, generated privately and locally using Ovis2-8B
🌱 Energy used: 0.394 Wh
Bella, questa ricerca!
Il nostro corpo emette luce in modo diretto e ritmico L'intensità della luce emessa è 1000 volte inferiore alla sensibilità del nostro occhio nudo. L'emissione di fotoni ultradeboli è nota come energia rilasciata sotto forma di luce attraverso i cambiamenti nel metabolismo energetico. Le variazioni diurne nell'emissione di fotoni potrebbero essere collegate ai cambiamenti nel metabolismo energetico, ma variano anche in relazione a stati meditativi o nella focalizzazione mentale.
researchgate.net/publication/2…
Fernando Zamora presenta el Plan País: Una nueva Costa Rica
Fernando Zamora presenta el Plan País: Una nueva Costa Rica
San José, 17 may (elmundo.cr) – El precandidato presidencial del Partido Nueva Generación (PNG), Fernando Zamora, invitó a la presentación oficial del Plan País: “UNA NUEVA COSTA RICA”. Este es un proyecto qu [...]
#CostaRica #DesarrolloSostenible #Elecciones2026 #FernandoZamora #HotelPalmaReal #JusticiaSocial #NuevaGeneración #PNG #PlanPaís #Política
elmundo.cr/costa-rica/fernando…
Fernando Zamora presenta el Plan País: Una nueva Costa Rica
Fernando Zamora presenta el Plan País: Una nueva Costa Rica Costa Rica - El Mundo CREdmundo (El Mundo CR)
Laura Chinchilla: “Chaves alienta las disputas y siembra el odio entre cuerpos policiales“
La expresidenta Laura Chinchilla afirmó este sábado que el presidente Rodrigo Chaves alienta las disputas y siembra el odio entre los cuerpos policiales. “El modelo policial de Costa Rica se caracteriza por la dispersión del mando, así diseñado por la legislación para evitar la concentración y el abuso de poder. De ahí que resulte fundamental […]
Gabriele Romano
in reply to Patrícia Nicoloso • • •