Hey Blog! Today I’ll tell you about that classic winter activity, common in any country where the rivers and lakes actually get cold and freeze (oh wait, not this one then. Annoying global warming!) – ice skating!
Like the best traditions, skating is well-tested, and has been used as a mode of transport since the ice age. Reindeer shin bones have been found bearing the unmistakeable scratches and attachments for being worn on the feet and skated with. Over the last millennium, metal skates have quickly come into fashion and are now found across the world in all the ice rinks in every major city. But apart from providing a tremendous opportunity to fall over if unpractised, and an incredibly cool way of moving about on a surface that doesn’t often form in this country, what is it that ice skating does?
Science alert! Skating is a bit like going on a hovercraft. Both involve moving fast over a denser surface supported on a small cushion of a less dense material. The skating version relies on the ice being compressed by your weight over a very small area. These formulae: pressure = force divided by area; weight = mass times gravitational field strength; and pressure = gravitational field strength times height times density, give the reason for this.
Weight, which is a force, is always the same on an ice rink, as neither mass nor the strength of gravity change. Therefore your force is the same. Decrease the area your force affects (by making the edge of the skate as thin as possible) while keeping the force, your weight, the same, gives an increased pressure exerted. The final formula therefore calculates the density of the water. Increasing the pressure while keeping gravity and height the same, increases the density. Ice is less dense than water – that’s why the ice in your drink floats and why the Titanic was able to crash into an iceberg and sink – so the denser ice becomes water. Hence you have a thin cushion of water on top of ice (which instantly freezes when you release your weight) which is what you float on. So yes, when you are ice skating, you are walking, well, skating, on water!
Skating is also fast for this reason. Hovercraft are able to go much faster than conventional boats because there is less friction between air and boat than between water and boat. Similarly, there is less friction between water and skate than between ice and skate. Because of this, skating is by far the fastest method to go over ice (unless you happen to have a specially trained pack of huskies and a dogsled. Surely someone has to have such a thing stashed in their shed?). Indeed, one person I saw on the rink this year was sliding from one end to the other in about five seconds – which is much faster than I could do walking. Therefore it is not just a way of keeping your footing, but also of going at greater speed.
The first time I realised the allure of skating was when I read the fourth book of the Swallows and Amazons series, Winter Holiday. After learning that sailors could become skaters and explore frozen lakes, I waited in hopeful anticipation of a proper winter. Proper winters, it turns out, do not come. So I remain bound to the ice rink until I ever go to a more meteorologically interesting country, like Canada or Iceland. However, at that point I had not been on an ice rink since I was six, and was outside the Natural History Museum in London, on a visit to the UK. With tiny feet in tiny skates, a stabilising plastic penguin that was about as big as I was, and a firm hold on the handrail, I managed to go around the rink a few times. I didn’t try again till last year.
Each year, the Explorer troop I am part of goes on a few Christmas activities. One of these is usually skating. The past two years we have been to the local ice rink, and skated with varying degrees of success. I started a bit unsteady, but slowly managed to grasp the technique. To my mind, it’s more like walking backwards flat-footed yet going forwards than anything else. The effort isn’t going into pushing your toes to go forward, it’s in stopping your heels sliding too far and falling over. Hardest, I have found, is stopping. You need to be keeping going on one foot, while dragging the other sideways, to stop quickly – therefore I find it easier to just stop propelling myself and drift, which takes longer but stops you the same way. However, I would consider myself in need of practice but understanding of the basics. Maybe I’ll try again soon!