Tag Archives: wave watching

#WaveWatchingWednesday

Leave a reply

It’s #WaveWatchingWednesday, and this is actually my 75th post in this series, recapping my wave watching pics from my Insta @fascinocean_kiel! For all of you new readers on my blog — wave watching (and #KitchenOceanography) is actually how I really got into blogging and social media a long time ago; I was in the habit of taking at least one photo of water every day, and explaining the physics in a short blog post. And those posts got a lot of engagement, both on- and offline, lots of fascinating discussions of physics. Sometimes I miss that… So even though now this kind of post might look a little out of place amongst all the academic development stuff I do now, this is really how it all started. Enjoy!

Continue reading →

#WaveWatchingWednesday

Leave a reply

Ha, I was so keen on getting to my morning swim that I scared one of the ducks so it didn’t just swim away (like the other one), but took flight for a meter or so, before it plopped back down into the water! Can you see it in the waves?

This one is for you @manelriveracamacho: an interference checkerboard pattern in capillary waves! And at the same time a really interesting case of total reflection: the whole green-yellow-ish part in the foreground is where we look directly at the slope of one side of a wave, and can look into the water because the angle is steep enough. For the whole blue area, including the one side of the capillary waves in the yellow-green-ish area, the angle is smaller, and in fact so small that we can’t look into the water any more, but instead see the reflection of the sky!

More super awesome capillary waves. See how they act like lenses and deform the straight-ish ripples in the sand into zigzags?

Continue reading →

“Evaluating shallow water waves by observing Mach cones on the beach” — guest post by Felipe Veloso on his recent #WaveWatching article!

Leave a reply

Super excited to share a guest post today: Felipe is writing about his recent #WaveWatching article on “Evaluating shallow water waves by observing Mach cones on the beach”. I came across this article and was going to write a summary, but how much cooler is it to hear from Felipe himself? Thank you for being here! :)

—

My name is Dr Felipe Veloso1 and I tremendously appreciate Dr Mirjam Glessmer invitation to write this post and letting me contribute to the terrific #WaveWatching collection!!

One of the spectacular things of #WaveWatching is that the observations are ubiquitous. It doesn’t matter if you live in Germany, USA, Japan or Chile. Oscillations and waves are there, whether you observe swimming pools, lakes, sea, or even a relaxing bathtub ready for you. In all cases, the water is always naturally oscillating in a comfortable dance combining up-and-down and back-and-forth movements. If you enjoy these natural phenomena like I do, invest some of your time and take a look to the wonderful #WaveWatchingWednesday and #KitchenOceanography collections that Mirjam has gathered for us. But there are some occasions that these wave phenomena are obscured to our naked-eye observations and a more careful revision is needed to figure out where these oscillations are hidden. A turbulent river coming down of a hill, or the simple passing of fast water flow in front of our eyes are some examples of “waves hidden at first sight”. Such situation occurred to me in the latest family vacations we had as a break from the lockdowns imposed by the pandemia. In particular, this situation became the reason of an article in Physics Education, and also the reason  of why I am writing these lines.

In an attempt to run away from the contaminated air of Santiago (the Chilean capital city, surrounded by mountains), we drove ~90 minutes to Viña del Mar city, to enjoy one week in the beach side. In this place, with the appropriate weather and personal calmness, families can enjoy the waves crushing the beach, the rising of children as “sand engineers”, and the “continuous fight” between these children and the ocean waves to avoid the destruction of the sand fortresses by the water. It is in this relaxing and family-friendly environment where my story begins.

My kids are playing in the sand and my feet are partially covered by water. After long time, we are able to come out from our houses after several months of mandatory quarantines, pandemic stress, and online teaching activities. In this particular moment, watching waves looks like a perfect panorama for me. Suddenly, the voice of my daughter Pilar wakes me up and asked me two questions: “Dad, what are you looking in the water?… and dad, why does the water creates those conical shapes at the end of the undertow current?” The first answer was easy. I was #WaveWatching. But the second answer was not so simple. What about those conical shapes?

Mach cones observed in the surface of undertow water produced by stationary millimeter grains/seashells in sand. Those feet belong to my daughter Pilar and myself. Image taken from the article.

Before her question, I haven’t thought on that. Rapidly, I realized I was observing a wave phenomena in a different and non-standard way. We were observing shock waves in the shape of Mach cones!! These cones appear when an object moves inside of a fluid with a relative velocity larger than the natural oscillation velocity of the fluid. In these situations, there is a shock occurring in the fluid itself. The tip of the cone (or V-) shape arises from the relative movement of the object, whereas the radial expansion of the wave creates the sides of the cone. This explains the formation of V-shapes in the water when a ship travels in a river, or when ducks swim in the lake. In the case of beach observations, the cones were originated by stationary small seashells or larger grains buried in the sand when the undertow water current returned back to the sea with depth not sufficient to immerse my toes.

Now, I am not really sure if my 8 years-old daughter or my 11 years-old son understood completely my explanations of waves and Mach cones. But, I am sure they understood that observing nature can be a fun and relaxing activity to enjoy in family vacations. As an exercise, I taught them how to compute the wave velocity by measuring these Mach cones. I also show them that we did not need any fancy or expensive equipment to accurately evaluate it. We only require interest and fascination on looking for an explanation of a natural phenomena… a phenomena that they could observe while enjoying the beach, the sand and the family time.

Family picture in Viña del Mar. My beautiful wife Alicia, my kids Diego and Pilar and myself. And of course, our dear dog Chewbacca trying to run away from the camera.

Further details can be found in the paper: Felipe Veloso (2021) “Evaluating shallow water waves by observing Mach cones on the beach” Phys Education 56, 054001.

  1. @fvelosoe in Instagram and Twitter

 

The ultimate guide to #WaveWatching, gooseling edition

4 Replies

I’ve been fascinated by gooselings recently, mainly because they are super cute. But I can tell you about what makes wave watching special when the waves are made by geese — it is an extra challenging type of wave watching! (Check out this post for a more general — and likely much more useful — guide to wave watching)

I dug through my phone (all these pictures are from this year, but they aren’t posted chronologically as you’ll see from the size of the gooselings) and found quite a collection. This is for you, Yasmin and Maike!

Let’s start out with a couple of pics that work well for wave watching purposes, but that already show hints of the challenges discussed below.

Here all three gooselings and the goose that is still closer to the shore are swimming fast and are making beautiful wakes; those feathery, V-shaped waves that are caused by them swimming faster than the speed at which waves can spread. The goose swimming in the front is swimming slower than that critical speed: See how there is a wave the goose is pushing in front of itself, but how it doesn’t break into these feathery structures? And the background wave field, those large curved waves, were likely caused when one of the large geese jumped into the water, or at least something close to the lower left corner of the picture falling at about the time it would have taken the front goose to swim  to where it is now at a slow (but typical) speed.

And here, the geese are doing what I’m always hoping I’ll snap a good picture of: Swimming exactly in a row. This should be energetically really good, because the goose swimming in front already creates the wake and lowers the resistance for all the other geese swimming in its wake. You see that both families are doing it in this pic, but then the duck still takes the price for the prettiest wake.

Here is another example of the front goose doing the hard work and the gooselings following in its wake. For some reason, geese never have such nice distinct wakes as ducks! Maybe it’s their bow shape in addition to their erratic swimming behaviour?

This picture gives you a glimpse of the problems we are about to discuss below. See the resting gooselings on the tree trunk in the right? Cute, but not helpful for wave watching. And the ones that are swiming, although making comparatively pretty waves, are changing speed and direction so much that the wave field looks quite messy. You can see they all started out fom the left side of the partly submerged tree trunk (the one the other family is sitting on on the right)

Here again: They CAN make petty waves if they choose to, but they are often moving quite erratically. Speeding up, slowing down, changing direction… But the right family is making pretty waves!

So why is it so difficult to get good pictures of geese-made waves? Continue reading →

#WaveWatching as “transformative experience”? (Based on articles by Pugh et al. 2019, 2011, 2010)

5 Replies

I was reading an article on “active learning” by Lombardi et al. (2021), when the sentence “In undergraduate geoscience, Pugh et al. (2019) found that students who made observations of the world and recognized how they might be explained by concepts from their classes were more likely to stay in their major than those who do not report this experience” jumped at me. Something about observing the world and connecting it to ideas from class was so intriguing, that I had to go down that rabbit hole and see where this statement was coming from, and if it might help me as a theoretical framework for thinking about #WaveWatching (which I’ve been thinking about a lot since the recent teaching conversation).

Going into that Pugh et al. (2019) article, I learned about a concept called “transformative experience”, which I followed back to Pugh (2011): A transformative experience happens when students see the world with new eyes, because they start connecting concepts from class with their real everyday lives. There is quote at the beginning of that article which reminds me very much of what people say about wave watching (except that in the quote the person talks about clouds): that once they’ve started seeing pattern because they understood that what they look at isn’t chaotic but can be explained, they cannot go back to just looking at the beauty of it without questioning why it came to be that way. They now feel the urge to make sense of the pattern they see, everytime they come across anything related to the topic.

This is described as the three characteristics of transformative experiences:

  • they are done voluntarily out of intrinsic motivation (meaning that the application of class concepts is not required by the teacher or some other authority),
  • they expand peception (when the world is now seen through the subject’s lens and looks different than before), and
  • they have experiential value (meaning the person experiencing them perceives them as adding value to their lives).

And it turns out that facilitating such transformative experiences might well be what distinguishes schools with higher student retention from those with lower student retention in Pugh et al.’s 2019 study!

But how can we, as teachers, facilitate transformative experiences? Going another article further down the rabbit hole to Pugh et al. (2010), this is how!

The “Teaching for Transformative Experiences” model consists of three methods acting together:

  • framing content in a way that the “experiential value” becomes clear, meaning making an effort to explain the value that perceiving the world in such a way adds to our lives. This can be done by expressing the feelings it evokes or usefulness that it adds. For #WaveWatching, I talk about how much I enjoy the process, but also how making sense of an aspect of the world that first seemed chaotic is both satisfying and calming to me. But framing in terms of the value of the experience can also be done by metaphors, for example about the tales that rocks, trees, or coastlines could tell. Similarly, when I speak about “kitchen oceanography”, I hope that it raises curiosity about how we can learn about the ocean in a kitchen.
  • scaffolding how students look at the world by helping them change lenses step by step, i.e. “re-seeing”, for example by pointing out specific features, observing them together, talking through observations or providing opportunities to share and discuss observations (so pretty much my #WaveWatching process!).
  • modeling transformative experiences, i.e. sharing what and how we perceive our own transformative experiences, in order to show students that it’s both acceptable and desirable to see the world in a certain way, and communicate about it. I do this both in person as well as whenever I post about #WaveWatching online.

So it seems that I have been creating transformative experiences with #WaveWatching all this time without knowing it! Or at least that this framework works really well to describe the main features of #WaveWatching.

Obviously I have only just scratched the literature on transforming experiences, but I have a whole bunch of articles open on my desktop already, about case studies of facilitating transformative experiences in teaching. And I cannot wait to dig in and find out what I can learn from that research and apply it to improve #WaveWatching! :)

—

Lombardi, D., Shipley, T. F., & Astronomy Team, Biology Team, Chemistry Team, Engineering Team, Geography Team, Geoscience Team, and Physics Team. (2021). The curious construct of active learning. Psychological Science in the Public Interest, 22(1), 8-43.

Pugh, K. J., Phillips, M. M., Sexton, J. M., Bergstrom, C. M., & Riggs, E. M. (2019). A quantitative investigation of geoscience departmental factors associated with the recruitment and retention of female students. Journal of Geoscience Education, 67(3), 266-284.

Pugh, K. J. (2011). Transformative experience: An integrative construct in the spirit of Deweyan pragmatism. Educational Psychologist, 46(2), 107-121.

Pugh, K. J., Linnenbrink-Garcia, L., Koskey, K. L., Stewart, V. C., & Manzey, C. (2010). Teaching for transformative experiences and conceptual change: A case study and evaluation of a high school biology teacher’s experience. Cognition and Instruction, 28(3), 273-316.

An iEarth teaching conversation with Kjersti Daae and Torgny Roxå on #WaveWatching

6 Replies

iEarth is currently establishing the new-to-me format of “teaching conversations”, where two or more people meet to discuss specific aspects of one person’s teaching in a “critical friend” setting. Obviously I volunteered to be grilled, and despite me trying to suggest other topics, too (like the active lunch break and the “nerd topic” intro in a workshop), we ended up talking about … #WaveWatching. Not that I’m complaining ;-)

After the conversation, I wrote up the main points as a one-pager, which I am sharing below. Thank you, Kjersti and Torgny, for an inspiring conversation!

—

I use #WaveWatching in introductory courses in oceanography and in science outreach both on social media and in in-person guided tours. #WaveWatching is the practice of looking at water and trying to make sense of why its surface came to look the way it does: What caused the waves (e.g. wind, ships, animals)? How did the coastline influence the waves (e.g. shelter it from wind in some places, or block entrance into a basin from certain directions, or cause reflection)? What processes must be involved that we cannot directly observe (e.g. interactions with a very shallow area or a current)? Kjersti Daae (pers. comm.) suggests an analogy to explain #WaveWatching: Many people enjoy a stir-fry for its taste, like we enjoy looking at water, glittering in the sun, without questioning what makes it special. But once we start focusing on noticing different ingredients and the ways they are prepared, it is a small change in perspective that changes our perception substantially, and leads to a new appreciation and deeper understanding of all future stir-fries (and possibly other dishes) we will encounter.

I teach #WaveWatching using a cognitive apprenticeship leaning (Collins et al., 1988) approach*: By drawing on photos of selected wave fields (in the field using a drawing app on a tablet), I model my own sensemaking (Odden & Russ, 2019). I coach students to engage in the process, and slowly fade myself out. Students then engage in #WaveWatching practice anywhere they find water – in the sink, a puddle in the street, a lake, the ocean. Since waves are universally accessible, this works perfectly as hyper-local “excursions” in virtual teaching: Students work “in the field” right outside their homes.

Waves are not an integral part of the general curriculum in physical oceanography. While some wave processes are relevant for specific research questions, for typical large-scale oceanography they are not. And the concepts used in #WaveWatching are not even new to students, they are just an application of high-school optics to a new context.

Nevertheless, #WaveWatching helps work towards several goals that are important to me:

  1. Using “authentic data” acts as motivation to engage with theory because the connection with the real world makes it feel more interesting and engaging (Kjelvik & Schultheis, 2019).
  2. Engaging in sensemaking and gaining experience on what can (and cannot!) be concluded from an observation are highly relevant skills and this is an opportunity for practice.
  3. Building an identity as oceanographer – seeing the world through a new lens, joining a community of practice (Wenger, 2011), but also being able to demonstrate newfound expertise and identity to friends and family outside of that new community by talking about this new lens – are otherwise rare in socially distant times.

After being exposed to #WaveWatching, people tell me that they can’t look at water in the same way they did before. They are now seeing pattern they never noticed, and they try to explain them or ask themselves what I would see. They often send me photos of their observation years after our last interaction, and ask if I agree with their interpretations. #WaveWatching might thus be a threshold concept, “a portal, opening up a new and previously inaccessible way of thinking about something” and where “the change of perspective […] is unlikely to be forgotten” (Meyer & Land, 2003).

—

Literature:

  • Collins, A., Brown, J. S., & Newman, S. E. (1988). Cognitive apprenticeship: Teaching the craft of reading, writing and mathematics. Thinking: The Journal of Philosophy for Children, 8(1), 2-10.
  • Kjelvik, M. K., & Schultheis, E. H. (2019). Getting messy with authentic data: Exploring the potential of using data from scientific research to support student data literacy. CBE—Life Sciences Education, 18(2), es2.
  • Meyer, J. H. F., and Land, R. (2003) “Threshold Concepts and Troublesome Knowledge: Linkages to Ways of Thinking and Practising” in Improving Student Learning: Ten Years On. C. Rust (Ed), OCSLD, Oxford.
  • Odden, T. O. B., & Russ, R. S. (2019). Defining sensemaking: Bringing clarity to a fragmented theoretical construct. Science Education, 103(1), 187-205.
  • Wenger, E. (2011). Communities of practice: A brief introduction.

*more on that in this post (that comes online on 21.5.2021).

Fun #WaveWatching today! Reflections all the way….and then the boundary suddenly ends!

Leave a reply

You might remember this edge here and the reflection situation.

More details in this recent post, but in a nutshell: The wave crests marked in red are approaching the beach and wooden edge, and where they hit the wooden edge, they get reflected and converted into the green wave crests which propagate away from the edge again.

And this is what the other side of the edge looks like: The reflections end where the edge stops!

Again, the red wave crests are the incoming waves, and the green the reflections. Waves always travel perpendicularly to their crests, so you see how they propagate away from the boundary and appear to be cut on the right side where the boundary suddenly stopped and no reflection could happen any more.

 

When you meet a hard boundary, the reflection starts

1 Reply

When I look at the picture above, I see basically three different zones on the surface of the lake.

The yellow zone, which is under the direct influence of the wind, where the water is full of small waves, and then two other zones.

In the red zone, the water isn’t under direct influence of the wind any more, we see clear, parallel wave crests propagating towards the shore. I’ve marked some of them below.

While they are still to the left of the wooden edge, not much happens. But once they hit the edge, we enter the “green zone”: The incoming wave crests get reflected at the wooden edge. They start propagating out onto the lake, getting longe and longer over time, while the red wave crests continue running further and further into the green zone, so we get interference between the incoming and reflected wave crests. Pretty cool! :)

DIY #WaveWatching “fortune teller” on #WaveWatchingWednesday

4 Replies

(Download in English || Download in Spanish; thanks to Felipe Veloso for translating!)

How about a little wave watching game to celebrate #WaveWatchingWednesday?

The minute I saw Andrea Lopez Lang’s tweet, where she made a “fortune teller” (no idea that’s what they were called) as going-away and please-remember-what-you-learned gift for her class, I HAD to make something like that!

Unfortunately I’m not teaching a class right now where I could easily see how this could be done, but luckily there is always wave watching!

Grafic with instructions to build a wave-watching-themed "fortune teller"

Click to get the pdf!

And Kjersti had a great idea for how this could be used right away: To send students out with these toys and ask them to discover one example for each of the waves shown on the toy. Plus then of course document it, and share on social media… ;-)

Waves are traditionally taught in a theoretical and very dry manner, and the transfer to the real world is hardly happening at all (especially since the large tank in the basement at GFI has been demolished, which still breaks my heart), so this is a fun way to get students outside and try & find contents from their lecture in real life.

P.S.: It’s not as difficult as it might seem at first once you start observing and get a little creative. Nobody said that the rock that makes the ring waves had to have been there when you got there, and wakes can be created by ships or bird or even if you pull a stick through the water…

#WaveWatchingWednesday

Leave a reply

Even though I haven’t done a #WaveWatchingWednesday in a looong time, there has of course been a lot of wave watching going on. But the longer I wait with copying all the Instagram posts into a blog post, the more work it gets, the longer I put it off. Vicious circle! But here we go today. Plenty of interesting and plenty of beautiful pics! Enjoy!

Continue reading →