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Physicist in motion

11/09/2016 | Face to face

An interview with experimental physicist Gernot Pottlacher is anything but dull. He paints pictures with words and underscores the spoken word with experiments on his desk.

Experimental physicist Gernot Pottlacher teaches, experiments and collects passionatly.
Experimental physicist Gernot Pottlacher teaches, does experiments and is a passionate collector. A glimpse into the world of practical physics. And, at the same time, a foretaste of the traditional Christmas lecture, which will be held this year on 14 December, when Gernot Pottlacher will demonstrate 55 experiments on levitation.

News+Stories: On 14 December you will demonstrate 55 experiments on levitation – what can visitors look forward to?

Gernot Pottlacher: This year our feet are not going to stay on the ground. On the one hand we’re going to do some genuine levitation, on the other, we’re going to reveal the tricks used by other people. As usual, they’ll be some loud explosions and sparks will fly – as everyone expects. Just like every year, I’ve prepared a few experiments just for the Christmas event. For instance, right now I’m trying to get the Levitron to work. (Takes out a circular object from a box). 
For this year’s Christmas lecture, a Levitron will be made to hover.
If you place two magnets on top of each other, one of them turns over immediately, falls over and that’s the end of the matter. But here, the second magnet is put into a spin; this spin keeps everything completely stable and the spinning top should hover due to magnetic force.  I’ve just been to Japan. Did you know that a one-yen coin can swim? (Goes to the wash basin and demonstrates)

How do you get your ideas for such experiments?

Gernot Pottlacher: There’s a certain play instinct behind it (laughs). In this job you can stay like a child forever. And the wonderful thing is, the older you get, the easier it is to buy your “toy”! I buy many objects for my experiments in the USA or I order them on the internet, which I’m always combing through in the search for new ones. I’m also a collector, and try to manage the treasures of our institute (stands on chair and pulls down an old book from the top shelf). This, for instance, is a really old book in which experiments which were carried out at TU Graz earlier are written down. It’s from the year 1893 and I like looking for ideas in it. Very old stories – wonderful drawings!  
Among the treasures of the Institute of Experimental Physics is a book of lectures from 1893.
I also find old catalogues of teaching aids and inventories very important. For instance, I’ve got a very old instrument here and I didn’t know what it was for over 20 years. By accident I found out that it’s a so-called hypsometer, and it comes up in the film “Die Vermessung der Welt” (Measuring the World). It can be used to measure the approximate height of mountains. Water boils at different temperatures depending on how high above sea level you are. At sea level it boils at 100 degrees, at 5,400 meters at 82 degrees.  

Is your home also a kind of museum? Do you also collect things in your private life?

Gernot Pottlacher: I do, but most of them I keep here. I have to do the dusting myself at home (laughs). I’ve always collected things. As a student I used make some money in the summer at flea markets. I collected things the whole year long and then sold them off on one or two occasions. It brought in a good amount of pocket money and at the same time an enormous knowledge about the value of these things.  

Where does your fascination for experiments come from?

Gernot Pottlacher: I had that fascination at school. We had one teacher who showed us lots of experiments, and another who only taught theoretical physics. I saw the difference very clearly. Also, I’ve also been very good with my hands. I’m very happy to get my hands involved. At home I repair everything myself – I don’t need any workmen. This ranges from the alarm system of my house to the 34-HP engine of our former VW van, which always broke down after every summer (laughs).
Old (physics) books belong to Gernot Pottlacher’s treasure collection. 

Do you also do experiments in private?

Gernot Pottlacher: I try to do this only at my office here. But of course I show a couple of entertaining tricks to my wife or in company occasionally. In my free time though, I’m usually busy with my big garden. And I’m a passionate fly fisherman. But that takes up a lot of time – especially when you make your own flies, as I do. Last summer I caught a 17-kilo carp using my own flies – that was really exciting. When I have more time, I want to occupy myself properly with cooking.  

You travel a lot professionally – how important are international activities for you?

Gernot Pottlacher: Very important. Although I’ve always been full time at TU Graz, I try to travel a lot. I’ve been to the USA on research stays many times. And I’ve just been to Japan, which fascinated me very much. And my most exciting stay was definitely many years ago in Russia, where I was supposed to open a conference where everyone only spoke Russian. That was an adventure (laughs). In fact, the only places I haven’t been to are Australia and South America. Most contacts occur at international conferences, where we all invite each other to various things. You have to stay open to the world.

What could the topic of the Christmas lecture 2017 be?

Gernot Pottlacher: We’ve already had experiments with candles, colours and electrons. Next year we might do foodstuffs. For instance, when you fry apples in liquid nitrogen, you could hammer a nail into the wall with them. Or if you put a wrinkled apple in a vacuum chamber, it becomes really nice again. 
Don’t experiment with these apples. 

Is that why there are apples on your desk?

Gernot Pottlacher: (Laughs) No, they’re from my garden. They’re not for experiments. They’re for me to eat.

“Pottlacher’s experiment lecture”
Date: 14 December 2016, 4:15pm
Place: HS P1, Petersgasse 16, Ground Floor, 8010 Graz


Gernot Pottlacher works at TU Graz’s Institute of Experimental Physics and heads the working group for thermophysics and metal physics to which Matthias Leitner, Thomas Leitner and Olivia Klemmer also belong. They primarily deal with liquid, high-melting point metals. At the moment, a comprehensive paper on the thermophysical properties of liquid aluminium is being prepared. The scientist is married with two daughters. 


Ao.Univ-Prof. Dipl.-Ing. Dr.techn.
Institute of Experimental Physics
Petersgasse 16
8010 Graz
Phone: +43 316 873 8149
E-Mail: pottlacher@tugraz.at