Comments on: Please discuss: Experimental setup for Nansen’s “dead water”

By: Explaining Nansen’s “dead water” observation with an experiment – Elin Darelius & Team

Mon, 06 Sep 2021 08:35:41 +0000

[…] considerations for using this specific experiment in teaching are described here, including the learning outcomes we hope to achieve with the experiment. Students read original […]

By: Explaining Nansen’s “dead water” observation with an experiment – Elin Darelius & team's scientific adventures

Mon, 28 Oct 2019 11:12:34 +0000

[…] considerations for using this specific experiment in teaching are described here, including the learning outcomes we hope to achieve with the experiment. Students read original […]

By: Demonstration: Nansen’s “dead water” in a tank! | Mirjam S. Glessmer

Mon, 22 Oct 2018 06:12:46 +0000

[…] setup for this experiment is discussed here and is based on the super helpful website by Mercier, Vasseur and Dauxois (2009). In the end, we […]

By: Mirjam

Mirjam — Thu, 18 Oct 2018 09:46:52 +0000

In reply to Anton Korosov.

We are a little scared what a propeller would do to the stratification since we want to use it a lot more often than just once ;-) But you are right, that would be the closest to reality.

The tank is 6m long and 15cm wide and we have about 40cm of water on it.

We’ve run the experiment several times now and I am only sitting on the movies until we’ve shown it to a couple of people in real life. But it’s really fascinating, I’ll post movies as soon as I am allowed to! :-)

By: Anton Korosov

Anton Korosov — Thu, 18 Oct 2018 09:22:53 +0000

Cool stuff!
Why don’t you use a small boat with a controlled propeller (or paddle wheels)? That would be even closer to reality ;)
How large is the tank and how large can be a boat? Would a boat with three AA batteries, micro-controller (pyboard) and two servos be small enough?

By: Mirjam

Mirjam — Wed, 10 Oct 2018 04:34:12 +0000

In reply to Joe Buchanan. Thanks, those are both really good ideas! I'll try and report back :-) And you are of course welcome to visit any time ;-)

By: Joe Buchanan

Joe Buchanan — Tue, 09 Oct 2018 22:22:43 +0000

I can think of two method for getting more horixontal distance from a limited drop distance. One is a z-drag set up. Hard to explain without a diagram but look at the wikipedia entry. Usually this is used to get a stronger force when pulling an object but reversed it means you can double the length of pull from a given height. The other way is to use a geared system – an old bike wheel would do if you have some bits and pieces lying around. Apply the force through a rope wrapped around the shaft of the wheel, but pull the boat from a rope around the perimeter of the wheel (take the tyre off). The distance around the perimeter will be much greater than the distance around the shaft. Actually you could probably just use an upside down bike, then you could change the speed with the gearing system.
Sounds like a great experiment – I wish I could be there.