The Swiss National Selection is held yearly, in December. The winning team has the privilege to represent Switzerland at the international stage of the IPT, which happens in a different location each year! For all updates, please see the IPT portal.
Following the format of the international competition, the participating teams have to work in advance on 2-4 problems among the five selected from the official problems list. They must be able to present a (possibly partial) solution to 2 of the problems and defend it against other participants and jury members. Participants must also be able to oppose or review two more, hence the need to work on a total of four problems.
The best solutions mix theoretical models and experimental measurements that, hopefully, match !
For more details about the principles of the competition, see the IPT portal.