dispersion – Adventures in Oceanography and Teaching

Refraction of waves towards the beach

mglessmer — Thu, 29 Jun 2017 11:08:04 +0000

As you see from my parents’ attire and the lack of leaves on the trees, these pictures are not brand new. But still interesting: Do you see how the waves are bent towards the coast as they run into shallower water? And can you believe I still have to look up which one is refraction […]

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Waves change their direction because of changes in water depth

mglessmer — Thu, 25 Aug 2016 11:36:33 +0000

When waves run up a beach, they change their direction because for shallow water waves, phase speed depends on water depth (see this post for a nice little visualization for why the whole wave crest swings in towards the beach). Unfortunately, it is really difficult to take good pictures of this phenomenon, but I tried: […]

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Observing hydrodynamic phenomena on a creek

mglessmer — Thu, 11 Feb 2016 11:48:29 +0000

Looking at a creek on a Sunday stroll, and seeing lots and lots of concepts from hydrodynamics class. For example below, you see waves radiating from each of the ducks. And you see interference of waves from all those ducks. What happens if the ducks bring their waves closer? At some point, all those waves from […]

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What are the ingredients of a rainbow?

mglessmer — Mon, 15 Sep 2014 04:21:22 +0000

Still collecting materials for our instructional short movies. A while back I talked about how my colleague and I were experimenting with short instructional screen casts, and I shared some first attempts at movies on how rainbows form. We are still working on a story board for an improved version, but I was lucky enough […]

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Why do we only see rainbows in the mornings and evenings, but never at noon?

mglessmer — Wed, 06 Aug 2014 04:19:26 +0000

Another movie on rainbows My dearest readers, I hope you are still as fascinated by rainbows as I am? Today I’m giving you another movie explaining something rainbow-related, namely why we do not see rainbows when the sun is too high up in the sky. The video is stylistically similar to the ones I did […]

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Rainbows III

mglessmer — Mon, 04 Aug 2014 04:01:39 +0000

Updated movie following Arne’s advice. When I asked for feedback on the rainbow movies the other day, Arne had a pretty good idea for how one of the explanations could be made more intuitive. I have other people’s comments still in the queue and I’m working on them, this is still very much in the […]

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Secondary rainbows

mglessmer — Mon, 28 Jul 2014 04:45:23 +0000

Sometimes you get lucky and see a double rainbow. But how does the second rainbow form? On my first 17th of May in Bergen, Ellen invited me to her home for a traditional dinner, which was exceptional. And as a bonus we got to see a double rainbow over Store Lungårdsvann! The outer rainbow is […]

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Rainbows and refraction II

mglessmer — Fri, 25 Jul 2014 04:48:17 +0000

Taking the same graphics as in this post, but presenting them differently. In the previous post, I presented a screen cast explaining, in a very text-booky way, how rainbows form. Today, I am using the same graphics, but I have broken the movie into six individual snippets. I’m starting out from the schematic that concluded last […]

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Rainbows and refraction

mglessmer — Wed, 23 Jul 2014 04:31:50 +0000

Why is a rainbow always red on top and blue at the bottom? We always talk about prisms and refraction and stuff, but be honest – would you be able to explain the order of colors in a rainbow without pausing and thinking first? As I said the other day, I am currently experimenting with screen […]

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