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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
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
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 · 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
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 · 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 · 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 · 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 · 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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