Adrien Thurotte

Oct 232017
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Even though I left the JUnQ Editorial Board over a year ago and am very busy in my job in industry, the desire for experiment never left me. The reason for experimenting in in my current job differs from academia – you need to earn money and usually do not publish your results. But one thing always remains the same: You get your fair share of failure!

Test of new colored ink in fountain and rollerball pens leaking (©Andreas Neidlinger)

When I heard about the photo contest JUnQ organized, I thought to myself: Why not submit a picture of my current experiments to provide proof that you will always have the same fun, even when your studies are over? What you see is no fancy laboratory equipment and no grandiose new discovery elegantly captured for the posterity. It is just some quality check and product development for the writing instruments industry. The outcome might not fulfil the customer’s needs and at first it caused a big laugh. Later, it meant more work. Just like in academia.
Some things never change
— Andreas Neidlinger

Oct 232017
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During the last months we have received a lot of funny pictures from our readers. Unbelievable how much inspiration you can find in labs and offices! Luckily, we did not have to choose since the winning picture was drawn by lot.
And here it is:

“Be happy if your laboratory experiment works! Bright smile :D”
– ©Esther Vogel

The winner is Esther Vogel with her photo of a magnified vascular bundle. If you look at it even more closely you might recognize a big-eyed, bearded smiley. Lucky are those, whose experiments smile back.
Esther is not only rewarded with the publication of her photo but also with an amazon coupon. Congratulations!
We thank all the participants and wish them good luck for the future.

Oct 232017
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Most of us know the ethical boundaries of social life in our respective cultures. “Be honest”, “Don’t steal”, “Don’t hurt or kill anyone” are just a few ethical codes that have been deeply imbedded in our minds ever since we were little children.

But what about moral codes in scientific life? Surely there must be some. But still simple rules like “Don’t kill” do not seem to keep scientists from injuring and destroying animals in pharmaceutical tests. And apart from the aspect of killing a living and sentient being: is it responsible to run trials on animals that have no or only minimal resemblance in their physiology compared to us? “Humans just aren’t
mice” is the statement from Dr Corinna Gericke. Read more in her comment on “Why animal experiments are not necessary” on page 9.

Not only researchers but also authors and editors of scientific journals must stay inside an ethical ramework to not generate a platform for fraud or enhancement but for honest and reproducible research. This applies also to negative and “null”- results. Are there any consequences for unethical behaviour in sciences? Find out what Brian Earp has to say in the interview on page 1.
As promised in our last issue we will also introduce you to the concept of Cradle to Cradle in an interview with Tim Janssen on page 5.

Of course, there is much more to explore about ethics in science and we already do have more in petto for our coming issues. Stay curious and dig through the JUnQ to find the hidden treasures!

Since there were no submissions for articles, unfortunately this section must be left empty.
Again, here comes the call to our readers: please help to raise the attention on JUnQ. Tell your friends and colleagues about the Journal of Unsolved Questions. There is no shame in null or negative results. Share your experiences with the world and help your colleagues to learn.
With this in mind keep digging through the JUnQ to find the hidden treasures in green sciences and green lives!

— Tatjana Daenzer

Aug 142017
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Sometimes they come and go with a bang, sometimes they are silent. They glow bright as a lightning in white, yellow, red or blue. They fly freely through the room and some of them even permeate solid matter. They all have in common that they appear mostly during stormy weather, are somewhat spherically shaped and have a lifetime of several seconds.[1] For many centuries people report about observations of lightning balls as depicted in figure 1.

Figure 1: Illustration of a ball lightning from the early 20th century.[2]

Clearly, ball lightnings cannot be the same phenomenon as a strong electric discharge like a bolt lightning since their effect is not as dramatic. A full scientific explanation is not yet found. Do they really exist or are they only the product of frightened people’s minds?

Sure, bolts can cause phosphenes, impressions in the focus of the eye that remain some moments after looking into bright lights.[3] But during the last years scientist came up with some experiments that deliver plausible explanations of their formation:

Abrahamson and J. Dinniss found out that after the impact of a bolt into the soil a cloud of Silicon (Si), Silicon carbide (SiC) and Silicon monoxide (SiO) nanoparticles evaporates and oxidizes in a timespan of several seconds. During this time the energy is released as a bright ball-shaped light.[4]

At the IPP in Garching, Germany, Prof. Dr. Gerd Fu?mann vaporized and ionized a tiny amount of water by an electrical discharge between two electrodes above a water surface. The glowing plasma cloud, called plasmoid, has a spherical or mushroom-like shape (shown in figure 2) and a lifetime below one second.[5] The appearance of these plasmoids is demonstrated in a short video on their web page:

Figure 2: Result of the water discharge experiment from 2014.[6]

Still these experiments lack to explain all the observed properties of a ball lightning: the free movement, the ability to permeate matter and the long lifetime of several seconds. It is plausible that there might occur spherical light phenomena during bolt impacts. An explanation of the rather vivid properties of a ball lightning is yet to come. But maybe they belong to the section of narrative decor.

– Tatjana Daenzer

Read more:

[1] Smirnov, B. M., Phys. Rep. 1987, 152, 177-226.


[3] Peer, J., Kendl, A., Physics Letters A, 2010, 374, 4797-4799.

[4] Abrahamson, J., Dinniss, J., Nature, 2000, 403, 519-521.

[5] Fussmann, G., Phys. Unserer Zeit. 2008, 5, 246-252.



Jul 242017
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Put a raw egg on a flat table, and give it a good spin with two fingers. The egg spins, however, rather slowly because the liquid inside poorly exchanges momentum with the outside shell. Thus, when you spin the egg by applying force to the shell, most of the inside resists the motion and the friction forces between the inside (immobile) and the shell (mobile) will be slowing down the egg’s speed. But if you consider a cooked egg, proteins contained inside the egg are now forming a solid phase that is tightly joint to the shell. In that case, there are no friction forces in the “egg system” and the movement is not slowed down.


In this case now, the only existing friction forces are those between egg and the support (the table) and the air (which can be reasonably neglected). If your initial momentum transfer is strong enough, you observe a strange phenomenon: the spinning egg starts to rotate upright.

The physical concept used to explain this phenomenon is inertia. Spinning ice skaters can reduce their moment of inertia by pulling in their arms, allowing them to spin faster. You can also sit on a swivel chair and spin on yourself. Extend your arms horizontally and you will slow down.  The same is happening with the egg. Friction forces tend to slow down the egg, and decrease overall energy. To save energy, like the skater, the egg stands up and the momentum of inertia consequently decreases.

To spin upright, the egg needs some energy, exactly as one needs some energy to get up in the morning, fighting against gravity. The necessary energy is provided by the rotation itself, and the change of orientation of the egg will only happen if the spinning is fast enough.




Video movement of interia

Bou-Rabee, N. M., J. E. Marsden, and L. N. Romero, A geometric treatment of Jellett’s egg, Angew. Math. Mech. (ZAMM) 85, (2005), 618-642

Jul 102017
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Ordinary glass as it is used for windows can exhibit exceptional behaviors and even shred a rifle bullet to pieces, furthermore it can help to make car windows safer and to understand the inner processes in volcanos.

Key to all these fascinating properties are the so-called Prince Rupert’s Drops. These structures are solidified drops of glass, which are produced by letting a drop of molten glass fall into a bucket of water. The sudden shock caused by the massive temperature drop on the surface of the glass basically locks in the outer shape of the drop, preserving main body and tail. (Fig. 1) [1,2,3].

Fig. 1: Prince Rupert’s Drops. The thick main body with the long, thin tail is well visible (Copyright: public domain). [1]

This object has now very unique properties: If the main body of the droplet is hit by a hammer, it practically never breaks. It even withstands a direct hit of a rifle bullet, whereas the bullet can be completely shred to pieces. All this the main body of the glass droplet can stand without breaking. However, if there is too much force applied to the fragile tail of the Prince Rupert’s Drop, or if it is even just nicked, the whole drop explodes into tiny pieces of glass that can spread over several meters. [4,5]

To understand how this fascinating behavior is created, we have to have a closer look at how the drop is created. Everything starts with a drop of hot, molten glass, suddenly getting in contact with water. As mentioned, the outer layer of the drop immediately solidifies and locks in the characteristic drop or tear shape. The thin tail is created when the drop detaches from its origin (e.g. the glass rod) and starts falling and also gets locked into its shape when touching the water for the first time. While the outer layers are now already solid glass, the interior of the drop is still a hot liquid (Fig. 2 top). Consequently, this glass contracts while cooling down and starts pulling the solid outer layers inward, stressing them just like an arch bridge is stressed (compressive strain) and thereby stabilizes the structure. Along the axis of the drop, however, the strain is not compressive but tensile, because the shrinking material tries to pull along the tail.

Fig.2: Mechanism of creation of a Prince Rupert’s Drop. The hot, liquid interior of the drop compresses against the already hardened outer shell. The result is a highly strained structure (Copyright: CC-BY JUnQ). [4,5]

These stresses make the round shaped main body of the drop extremely resistant to external disruptions, whereas the tail constitutes a weak spot (Fig. 2 bottom). If the latter is now damaged in any way, the energy stored in the mechanical stress can be released and a mechanical failure front runs through the material, destroying more and more of it until the main body is shredded into dust. This process can happen with a speed of around 1600m/s, just like an explosion, and it usually only ends with the pulverization of the whole drop. Thus, this is the secret of the Prince Rupert’s Drop; it is always experiencing extreme internal stress that makes the convex part so extremely stable (like an arch bridge) that even rifle bullets shatter on them.

Finally, in its cooled state, the drop represents a system that exhibits extreme internal stresses. These stresses make the round shaped main body of the drop extremely resistant to external disruptions, whereas the tail constitutes a weak spot (Fig. 2 bottom). If the latter is now damaged in any way, the energy stored in the mechanical stress can be released and a mechanical failure front runs through the material, destroying more and more of it until the main body is shred to dust. This process can happen with a speed of around 1600m/s, just like an explosion, and it usually only ends with the pulverization of the whole drop. Thus, this is the secret of the Prince Rupert’s Drop; it is always experiencing extreme internal stress that makes the convex part so extremely stable (like an arch bridge) that even rifle bullets shatter on them.

So, we can ask whether this effect can be useful for anything. The answer is yes, indeed. Exactly the same principle is used in tempered glass like it is used e.g. in car windows. This glass does not shatter into sharp shards, but instead produces relatively smooth and small pieces and therefore is less harmful for the passengers of the car in case of an accident. Currently, Prince Robert’s Drops are even researched to understand better the quick cooling of volcanic lava under certain circumstances and therefore the inner processes within a volcano. Thus, all in all, these fascinating objects are full of wonders.

— Kai Litzius

Jan 032011
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Publish or Perish…?

Frequent publications draw attention to scholars, help to ensure continued funding, and are crucial to further a career in academie. In consequence, scientists suffer constant pressure to publish new work frequently and spend considerable time writing papers. Is this compatible with the principles of science? And what are the principles on which modern natural science is based?

In loose succession, we will explore and scrutinize publication practices currently common in natural sciences and investigate how they affect scientific research.

First lecture: “Honesty in Science” on April 13th, 2011 by Prof. Dr. Siegfried Hunklinger, Ombudsman of the Deutsche Forschungsgemeinschaft,

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When: 10.15 a.m. Where: University of Mainz, Philosophicum,  Jakob-Welder-Weg 18, Auditorium P4

Further dates and lectures:

Panel discussion: “Publish or Perish…? Verfuehrt der allgegenwaertige Publikationsdruck Wissenschaftler zu Unehrlichkeit?”


May 23rd, 5.00 pm,Hermann-Staudinger Lecture Hall, Ackermannweg 10, Mainz (Max-Planck-Institute for Polymer Research)


Jan-Martin Wiarda, DIE ZEIT

Confirmed Debaters:

Prof. Dr. Gernot Kostorz, Editor-in-Chief of Acta Crystallographica Section A

Prof. Dr. Gerhard Froehlich, Institute for Philosophy and Theory of Science, Johannes Kepler University, Linz

Prof. Dr. Horst Kunz, Institute for Organic Chemistry, Johannes Gutenberg-University, Mainz

Dr. Peter Goelitz, Editor-in-Chief of “Angewandte Chemie”

Prof. Dr. Katharina Al-Shamery, Ombudsman for Science, Carl von Ossietzky-University Oldenburg

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Lecture: Publications – the wealth of science?

June 8th, 2011, 3.15 p. m, Staudingerweg 9, Mainz, seminar room of the Graduate School Materials Science in Mainz, room 03-122 (3rd floor)

Prof. Dr. Stefan Hornbostel, Institute for Research Information and Quality Assurance