On Saturday there was the open day at DESY in Hamburg in conjunction with the science night in Hamburg. More than 13000 people visited DESY to take a look at the large science center. As I was still travelling until Friday, I was not involved in the preparation of the open day and therefore was surprised to see what was prepared. The open day was masterly prepared so that nobody gets lost on our site. Every visitor received a small map where the buildings with things to see where highlighted and even a bus shuttle service was in place to bring the people quickly from one end to the other. What I liked a lot where the colored spotlights giving some different look of buildings or trees – a very nice atmosphere.

Lively discussions in the exhibition area of the Hera-West Hall.
One of the experimental halls of the former Hera accelerator – Hera West – was being prepared for public tours recently, and of course part of the exhibition on Saturday. In the hall different samples of high energy physics detectors were on display, the biggest being the Hera-B experiment itself.
The visitors also had the possibility to walk the ~1.5 km from the Hera-B experiment to the next Hera experiment H1 through the Hera tunnel (25m under ground). This was a very popular tour and people were lining up for up to one hour to get down to the tunnel.
I think it is very important for scientists to talk to non-scientists once in a while and to try to explain what all this is about in a language understandable for non-scientists. After all, our science is funded by tax money, paid mostly by non-scientists. So we owe the tax payers a good explanations why we need all this huge machines and fancy detectors. I spend a few hours in the Hera-West hall close to some of the exhibits answering questions. As most people visiting such an open day are very interested and open-minded, the discussions are lively and fun. And the people also have a lot of real good questions. I usually have a lot of fun and enjoy the discussions with people from all different backgrounds. Open days are a great invention!

Many people enjoyed a trip from Hera-B experiment to the H1 experiment through the Hera tunnel.