The Way of the Geophysicist.

Fluid dynamics is just boring equations, right?
Well have a look at this video and think again!



Food-dye is always fun, especially when you get to mix it and get some colourful joy. But this is just amazing how this liquid creates "laminar flow". If there were turbulences in the fluid while turning, you would not get the droplets nice and separated in the end.

Very similar equipment is used to determine the viscosity of fluids. You measure the torque you need to turn the object in the middle and from this you can calculate the viscosity of the fluid where the droplets are in the video. This is a great example how to visualize some pretty tough science in a very good way.
When I took a class on fluid dynamics, I had a pretty hard time visualizing viscometers and the different impact of turbulent vs. laminar flow. This would have probably helped to get a better start into the topic. In the end fluid dynamics is essentially everywhere and the difference between turbulent and laminar flow are pretty important in a vast amount of applications.
The Fraunhofer Institute is looking into sharkskin mimicry for planes and ships to reduce fuel consumption¹. The surface of planes and ships significantly accounts to fuel consumption due to aerodynamic drag. Modifying these to facilitate turbulent flow will reduce the drag and make travelling more economic and reduce the impact on our environment.

Read the full story about it about awesome fluid dynamics on A Science-based life

A wonderful TED note on science communication²:



You don't need to be a fabulous presenter.
You don't need to publish all your research in Nature.
You don't need to make it perfect.

Go out there, tell people about your fascination. Maybe start with a friend or your family. Their probably not great for for constructive criticism, but they are practice and they will give you confidence. Go out and partake in a competition like a Science Slam or Famelab. Maybe start a blog or send out tweets about your fascination.

This is not just for your audience. As Einstein put it:

If you can't explain it simply, you don't understand it well enough.

I absolutely agree with this quote, as it is what I experienced very often, with myself and also with others.

Go out there, share what you know and love!
You know something and that something is beautiful, don't be selfish, share it with your audience.

Within the last days a couple of amazing physics videos have been passed along on Twitter. My personal favorites are the two I want to talk about now. They basically involve some sort of experiment with oscillation or wave-like motion, with a twist. But see the first video for yourself:

Coupled pendulums

Personally I find it amazing. 32 metronomes start out completely independent on a moving table and they gradually align!
First of all the choice of colors is very beautiful but has no effect on the experiment, however, the weight of the metronomes are approximately set to match the same speed. The weight on a metronome determines the vibration period by the inertia set on the lever. This or a multiple of the base inertia is necessary to make this experiment work.

Why do they line up?

The metronomes are on a moving table and therefore can be viewed as a coupled system. Every metronome exerts a force on the moving table and opposing forces cancel out. With 2^5 metronomes you can be certain that at some point of time some metronomes will exert a force into one direction that is stronger than the opposing force, slightly moving the table to that side. Now this is where the coupling really comes into effect. When the table moves the period of the pendulum in direction of the movement of the table will be reduced, forcing the pendulum to swing to the opposite direction faster. On the other side (literally) the pendulum motion will be elongated, extending the movement in that direction. So in this exact moment the metronomes started to align just a little bit. Of course in the very next moment a couple of the other metronomes might exert just a different force which makes the entire process quite complicated. However, if we wait long enough the resonance of these pendulums will cause the metronomes to line up. Amazing right?
Now take another look, they line up pretty quickly for such a bulk of different complicated forces influencing each other, however at 2:11 You see something interesting happening. Far on the right in the pink row, the second metronome from the front, is aligned, but exactly opposite to the other metronomes. You can hear, it's lined up by listening to the sound of the metronomes. This is quite interesting because it takes quite some time for the last one to line up and this is because the counterweight is in sync with the movement of the table. Eventually it will line up because  the metronomes are attenuated and once the metronome is just slightly getting out of sync the table movement will force the last metronome to line up.

Why do you care, you're a geophysicist?!

First of all, they're colorful and cool and those metronomes are pretty mesmerizing.
Those metronomes are reminding me a lot of geophones. The good ol' mechanic geophones work with a spring and a weight and hopefully some kind of attenuation. Those geophones are put on a moving "table" aka the ground and you measure the force exerted on them and every time a new movement comes in, the spring and weight in the geophone are affected again. Now I was talking about attenuation and there is a reason for it. Without attenuation the forces on the metronomes and the forces on the spring and weight would sometimes build up without any counterweight stopping the motion, which would result in a lot of broken geophones or quite some pendulums ripped off of metronomes.

Uncoupled pendulums

I told you there was a second awesome video. Well this is just beautiful. Fifteen weights on a string with linearly increasing length: Continue reading "Curse of a geophysicist: Those waves!"