This past weekend, CERN held its first open days for the public in about five years. This was a big, big deal. I haven’t heard any final statistics, but the lab was expecting about 50,000 visitors on each of the two days. (Some rain on Sunday might have held down attendance.) Thus, the open days were a huge operation — roads were shut down, and Transports Publics Genevois was running special shuttle buses amongst the Meyrin and Previssen sites and the access points on the LHC ring. The tunnels were open to people who had reserved tickets in advance — a rare opportunity, and one that is only possible during a long shutdown such as the one currently underway.
A better CERN user than me would have volunteered for the open days. Instead, I took my kids to see the activities. We thought that the event went really well. I was bracing for it to be a mob scene, but in the end the Meyrin site was busy but not overrun. (Because the children are too small, we couldn’t go to any of the underground areas.) There were many eager orange-shirted volunteers at our service, as we visited open areas around the campus. We got to see a number of demonstrations, such as the effects of liquid-nitrogen temperatures on different materials. There were hands-on activities for kids, such as assembling your own LHC and trying to use a scientific approach to guessing what was inside a closed box. Pieces of particle detectors and LHC magnets were on display for all to see.
But I have to say, what really got my kids excited was the Transport and Handling exhibit, which featured CERN’s heavy lifting equipment. They rode a scissors lift that took them to a height of several stories, and got to operate a giant crane. Such a thing would never, ever happen in the US, which has a very different culture of legal liability.
I hope that all of the visitors had a great time too! I anticipate that the next open days won’t be until the next long shutdown, which is some years away, but it will be well worth the trip.