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The MEaSURE Project

@themeasureproject.bsky.social
9 followers 10 following 35 posts

Join a bi-annual, global experiment to calculate Earth's radius! I'm a STEM teacher based in Pennsylvania, USA looking to get classrooms around the world collaborating.

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The MEaSURE Project @themeasureproject.bsky.social · 27/09/2026
Adding multiple beams is a lot harder than overlaying images...I don't know how accurate this is but it's a first attempt. It may be that where beams overlap the colors get washed out, and you still may have red/blue fringes on either side.
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The MEaSURE Project @themeasureproject.bsky.social · 27/09/2026
This is absolutely amazing. I wonder if I can adjust my simulation to account for this. Thanks for introducing me to this topic! rainbowspec.observer/fog/
rainbowspec.observer
Fogbows and Drop Size
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The MEaSURE Project @themeasureproject.bsky.social · 27/09/2026
That's fascinating! My simulation doesn't include the diffraction that causes that. I will have to be on the lookout for a fogbow!
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The MEaSURE Project @themeasureproject.bsky.social · 27/09/2026
I never thought to count! I'm at 157 right now, but I'm making more all the time.
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The MEaSURE Project @themeasureproject.bsky.social · 27/09/2026
If you're more of a Pink Floyd fan, then you might prefer the triangular prism refraction demonstration. www.desmos.com/geometry/kqs...
An interactive Desmos graph shows how a beam of light refracts twice - once upon entering, and again upon leaving - a triangular prism. This is the origin of the iconic image on the cover of the Pink Floyd album "Dark Side of the Moon"
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The MEaSURE Project @themeasureproject.bsky.social · 27/09/2026
For the #BlueSkyArtShow, I'm going to take "any art, any interpretation" very, very liberally and share this interactive #Desmos graph I made that shows how rainbows are made from #Lights through a water droplet. "Reverse contrast" in the settings so it looks like: www.desmos.com/geometry/pzt...
A beam of light refracts when it enters a water droplet at an angle; it reflects off the back on the inside, and refracts again when leaving the drop. This spreads the colors of light so that depending on a viewer's position, the drop will appear to glow with a particular color. When many drops in many positions do this, you get the familiar rainbow.
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The MEaSURE Project @themeasureproject.bsky.social · 26/09/2026
For less obvious reasons...A and C both look like symbols (N and √) so B is the odd one out there. A looks like it could be made from the most pieces (three lines and a cubic). C probably has the smallest integral, since it's the only one to go negative.
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The MEaSURE Project @themeasureproject.bsky.social · 26/09/2026
It's funny, I didn't expect ALL of them to be non-differentiable! But the first one appears to be the only one with an inflection point. The second one is the only one that doesn't appear continuous, and the third one is the only one made entirely of straight lines.
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The MEaSURE Project @themeasureproject.bsky.social · 26/09/2026
According to a magnetic declination map, I should expect about 11º from magnetic north. The expected was 11.7º, and my measured was 13.8º declination. Although, I had done the experiment the previous day and found that my compasses' north on Wednesday wasn't exactly the same as on Thursday 😅
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The MEaSURE Project @themeasureproject.bsky.social · 26/09/2026
Clearly, my camera and gnomon are not quite stable enough to remain perfectly still in even a slight breeze. I might want to invest in a better setup, or at least stabilize the video! There is a 2º difference between expected and measured solar noon, but the shadow length differnce is negligible.
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The MEaSURE Project @themeasureproject.bsky.social · 26/09/2026
Happy September, everyone! Whether you're enjoying autumn in the northern hemisphere or spring in the southern hemisphere, we're entering a season of moderate temperatures. I have been able to make some measurements this week...a full analysis to come, but I can share this in the meantime:
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The MEaSURE Project @themeasureproject.bsky.social · 23/06/2026
Here's how I used #Desmos to model a shadow's path across the ground on the solstice! You may find this method interesting or useful if you plan to join the MEaSURE Project this September, calculating Earth's radius in a global science experiment. youtu.be/F1Pv80Vwukk
youtu.be
Modeling the solstice shadow
YouTube video by The MEaSURE Project
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The MEaSURE Project @themeasureproject.bsky.social · 22/06/2026
I'll have to finish this tomorrow...for now, here's a preview of my model! youtube.com/shorts/m6zLG...
youtube.com
MEaSURE #experiment for shadow measurement
YouTube video by The MEaSURE Project
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The MEaSURE Project @themeasureproject.bsky.social · 21/06/2026
Doing a test experiment on today's solstice...results to follow!
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The MEaSURE Project @themeasureproject.bsky.social · 20/03/2026
May I feature this picture on the website?
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The MEaSURE Project @themeasureproject.bsky.social · 20/03/2026
Results updated! Combinations you don't see (1,5 and 2,4) were measured at the same location. I'm a little puzzled, because I thought I saw different numbers in there a minute ago. Will double check that everything is good on my end. Great job!
A table of results for the MEaSURE Project, showing calculations for Earth's radius for pairs of participants. The average value is 6,071 km with a percent error of -4.71%
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The MEaSURE Project @themeasureproject.bsky.social · 20/03/2026
Happy equinox! If you're interested in making a measurement, here is a demonstration of the submission process. I also include a review of the results/analysis available to the public. youtu.be/PvO_FaWJnJI
youtu.be
Data submission demo - The MEaSURE Project
YouTube video by The MEaSURE Project
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The MEaSURE Project @themeasureproject.bsky.social · 16/03/2026
This Friday, March 20th, let's do an experiment! The sun is directly over the equator on the equinox, which means that you can directly determine your latitude with a shadow. If we are east/west of each other, the time difference between our noons gives us a longitude. We can measure the Earth!
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The MEaSURE Project @themeasureproject.bsky.social · 16/03/2026
Thanks for this! I'm gearing up for this experiment...I hope my weather is favorable 😶‍🌫️
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The MEaSURE Project @themeasureproject.bsky.social · 24/10/2025
The corners of each triangle are draggable, and it only works for angles in the first quadrant.
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The MEaSURE Project @themeasureproject.bsky.social · 24/10/2025
Here's a visualizer I made in Desmos to show to my students! www.desmos.com/calculator/m...
desmos.com
Angle Sum Identity
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The MEaSURE Project @themeasureproject.bsky.social · 24/09/2025
If you made a measurement this past equinox and haven't submitted it yet, please do! I will include it and update the results accordingly. If you find this project worthwhile or interesting, good news! There's another equinox in the spring! sites.google.com/view/themeas...
sites.google.com
MEaSURE
Measuring Earth's Size Using a Revision of Eratosthenes
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The MEaSURE Project @themeasureproject.bsky.social · 24/09/2025
With three measurers come three PAIRS of measurements. This means three independent calculations of Earth's radius.
This is a table of values of Earth's radius, calculated by the MEaSURE Project. The average value is 6,162 km, which has a -3.28% error.This histogram shows a tight cluster of values around the accepted mean radius of 6,371 km.
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The MEaSURE Project @themeasureproject.bsky.social · 24/09/2025
Not unexpected, but participation is starting off slowly. I am hopeful that participation now will encourage more participation later. The best part is, every equinox's astronomical conditions are identical, so previous entries can still be part of the calculation! We have three data points so far.
Three locations: northeastern USA, eastern Canada, and Europe submitted measurements so far.
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The MEaSURE Project @themeasureproject.bsky.social · 24/09/2025
Happy 2nd day of Fall! Fortunately I had the day off today (Happy Rosh Hashanah) so I was able to process the data and crunch the numbers. The results and data are available at my website now, but if you want to see a summary, read the thread! sites.google.com/view/themeas...
sites.google.com
MEaSURE - Results and analysis
Results and analysis
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The MEaSURE Project @themeasureproject.bsky.social · 22/09/2025
🥳 First response! Thanks for participating!
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The MEaSURE Project @themeasureproject.bsky.social · 22/09/2025
Unfortunately, it's cloudy where I am today. I was prepared to take three classes outside to measure shadows! But I won't be able to contribute any measurements today. I'll try again in the spring!
A satellite image showing clouds over central Maryland and PennsylvaniaAn image of the sky over my school. It is overcast and the sun doesn't appear through the clouds.
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The MEaSURE Project @themeasureproject.bsky.social · 15/06/2025
Oh my goodness, these are awesome!
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The MEaSURE Project @themeasureproject.bsky.social · 13/06/2025
1. Find a flat, level surface 2. Set up a vertical ruler 3. Find true North (northern hemisphere) or true South (Southern hemisphere) 4. Wait for the equinox 5. Measure the length of the shadow at solar noon 6. Record the time of solar noon (UTC) 7. Go to the MEaSURE website and submit your data
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The MEaSURE Project @themeasureproject.bsky.social · 10/06/2025
Math teachers! I have your lesson plan for the next equinox...Monday, September 22. Join a global experiment to calculate Earth's radius! youtu.be/myvEWdLU_1E #iteachmath #math #maths #teach
youtu.be
The MEaSURE Project
YouTube video by The MEaSURE Project
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The MEaSURE Project @themeasureproject.bsky.social · 01/06/2025
New short! First short, actually 😅 youtube.com/shorts/r9rtr...
youtube.com
The MEaSURE Project #mathematics #school #experiment #math #maths #globe #short #science
YouTube video by The MEaSURE Project
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The MEaSURE Project @themeasureproject.bsky.social · 31/05/2025
@petraschwer.bsky.social Thank you for sharing my post! This experiment's first attempt was done with help from a school in Leinfelden-Echterdingen, not far from you!
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The MEaSURE Project @themeasureproject.bsky.social · 31/05/2025
Hello STEM teachers! As the school year wraps up and you begin to make plans for next year, I've got something you might like to check out! This experiment can be done anywhere in the world, from elementary to advanced. See the video for details! youtu.be/myvEWdLU_1E
youtu.be
The MEaSURE Project
YouTube video by The MEaSURE Project
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The MEaSURE Project @themeasureproject.bsky.social · 03/05/2025
To organize participation and distribute resources, I've built a simple website. Whether you're curious or you want to participate, come check it out! sites.google.com/view/themeas...
sites.google.com
MEaSURE
Measuring Earth's Size Using a Revision of Eratosthenes
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The MEaSURE Project @themeasureproject.bsky.social · 03/05/2025
Hello! This is The MEaSURE Project. I am organizing a bi-annual experiment among schools, students, and lifelong learners to measure Earth's radius. Please watch this informational video. Consider participating, and spread the word! youtu.be/myvEWdLU_1E
youtu.be
The MEaSURE Project
YouTube video by The MEaSURE Project
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