With the start of the 2018 Winter Olympics it seemed my local newspaper The Volkskrant a great idea to include a segment on one of the great unsolved problems in physics: ice scating. If you look at the current unsolved problems Wikipedia page the official list contains the heavy-weight issues from particle physics , astronomy and so forth but humble ice-scating?
To recap the article (by Martijn van Calmthout), Professor Oosterkamp of Leiden University explains that the current theory on scating (friction between the skate and the ice melts a layer of water providing lubrication) fails when the skaters increase their speeds. The interest of a Dutch professor in speed skating is no coincidence as the Dutch are only anywhere decent in competing in winter olympics in speed skating events. IN 2017 another Dutchman Hans van Leeuwen calculated that at higher speeds the water layer is too thin to provide the required lubrication (DOI). To rescue the model, he then postulated a refinement: at relative slow speeds the skates plough through the ice with increased friction, a friction that is reduced at higher speeds with less ploughing, much like a catamaran in water.
With the van Leeuwen theory in place the article continues, the laboratory verification is now up to Oosterkamp. He is currently busy at work but already retired and complains about lack of funding and lack of PhD students. So if you are an ice skating enthusiast and interested in solving fundamental problems in physics and well-funded? Leiden University!