Monday, November 02, 2020

Solving The Rainbow Road Mystery

 In last week's Countdown post I posted a photo of a rainbow on the newly paved street in our town. There were questions about what made such a thing. I really had no idea, so I emailed my most favorite Atmospheric Optics person on our beautiful earth, Les Cowley. I sent him the photo and asked him what he thought would generate  rainbow on pavement. Not only did he have the answer, he already had a post on his website about it. His explanation there says, "Glass spheres make 'rainbows' in the same way as spherical raindrops. Light internally reflected once produces a primary bow. Its radius is only ~21° compared to the 42° of a water rainbow because glass refracts light more strongly than water."


So, when we were out walking Roger noticed this in the gutter and bent down to scoop some of it up. I thought, "Ugh, that looks creepy. Why is he touching that? Ugh." Then he showed me what he saw in this pile of stuff.

Tiny, tiny spheres of glass. Lots of it too. Here is a closeup of them.

Isn't that wild? We were so happy that Roger found them. The mystery was solved. There was one more thing I wanted to do. I read that rainbows actually can be full rainbows, not just the beautiful arcs we see. The full rainbow is harder to see because usually the lower part is below the horizon. So when we went to the sunny spot where the rainbows are I took another photos so we could see the bottom of that full bow. 

I hope you click on the pics and get a look at this rainbow road. Isn't it fun to solve a mystery! Yes!


35 comments:

  1. Oh wow, yes I CAN see the 360 degree rainbow. So we were right - recycled glass being used in road construction. That is a positive thing for our poor planet.

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    1. Dr Michelle-- Wouldn't it be lovely to see a raindrop rainbow like that in 360 degree. Yes to recycled glass!

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  2. Good for you! Enjoying the view, and finding out the cause. I never heard of glass in pavements...but I guess those little bubbles won't hurt anything.

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    1. Barbara-- I love solving mysteries like this. Things that have color and reflection make me start my hunt.

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  3. I’m glad you confirmed that my analysis was correct :). After I thought about it I had to conclude it was spherical “droplets”. It’s cool he already had posted about it.

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    1. Mark-- Yes, you were correct!! I love that you figured it our and Les had already posted about it.

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  4. Well that does make perfect sense. So glad you followed up and found the answer. And here I was thinking it was just you. Well in a way it was. For you not only look but you see. A gift too many of us lack.

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    1. Patti-- It does make sense. I'm so glad we spotted it out on our daily walk. A reliable bit of beauty lately.

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  5. That’s one of the neat things about science — it allows you to make predictions about things that you don’t know about.

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    1. Mark-- Yes! Science is a great tool for making sense of new things.

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  6. yep, glass bead. it's also used for sandblasting. I think I knew that rainbows are really circles. I wonder if there is any way to ever see that. in a plane maybe?

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    1. ellen-- I googled full rainbow and saw some images. Yes, most were views from airplane windows. It really is pretty spectacular.

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  7. Cool! Most people would just walk on by.

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    1. Red-- I love seeing stuff like this and finding out what it's all about.

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  8. I love how you find such beauty and joy wherever you look! Thanks for taking the time to find the answer for us!

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    1. EllenD-- Beauty is my favorite balance to the times we're living in. I love sharing the answers.

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  9. Thanks for solving that mystery. You find so much detail in your world.

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    1. Sabine-- I love looking around and finding things that spark my curiosity.

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  10. But why, I'm wondering, do they use glass beads in their paving project?

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    1. Catalyst-- Good question, I googled glass bead paving and found a product on Amazon. Here is some of the text about the product:

      INCREASE SAFETY & NIGHTTIME VISIBILITY: The glass spheres vibrantly reflect light from headlights or other light sources to increase visibility, illuminate hazards or capture attention

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  11. Neat bit of detective work. I saw another rainbow today, another full double one.

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    1. Billy-- It was fun detective work. We enjoyed it. A great diversion from our sheltered lives. So glad you saw a rainbow. We're expecting some rain this week, so maybe we will too!

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  12. Fascinating! Love your blue shadow and the full rainbow. Now I'm thinking about The Glass Bead Game, by Hermann Hesse (-:

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    1. am-- I'm so glad you liked this. We had fun with it. I love the connections you make. So interesting.

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  13. The little glass pieces Roger picked up were really neat. Do you think that they are just excess that ended in the gutter? I really liked that you took a picture of the total orb of the rainbow, and shared it. Thank you!

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    1. owl-- I think they just poured a lot of the glass beads and some just ended up in the gutter. I was so glad he spotted it. Glad you like the full rainbow pic. Thank you.

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  14. Robin. It's Jesus, trying to exit his tomb by election day. Read your scripture.

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    1. Phil-- Hah! Thank you for the laugh. Scripture? What is that?

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  15. Interesting! I wonder what all those little spheres are, and why are they there? Are they just pieces of silica sand, do you think?

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  16. Oh, I read the comments above about glass beads being used in paving. Who knew?!

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    1. Steve-- We did not know at all about the glass spheres being used in pavement. Just noticed the rainbow and went on a discovery mission. It was a fun distraction for a few days.

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  17. And now I know a few things I didn’t before reading this post, Robin. While I haven’t seen the rainbow you’ve posted about, it was interesting to see the photo and read why.

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    1. Beatrice-- I'm always happy to explain a bit of the details of what I'm seeing.

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