A scientific look at the efficiency of curling brooms by Jenni Gill

Review of Literature:
        The purpose of this experiment is to find out which curling broom works the best. A curling broom works because of the friction between the head and the ice.  Friction is the force that resists movement when two objects are touching each other. There are two types of friction, static and kinetic. Static force of friction is when neither of the objects is moving. Kinetic force of friction is when one or both objects are moving. When an outside force is applied to an object that object will not move until the outside force is greater then or equal to the static force of friction. Once this is met the object will move, kinetic friction will be acting upon it instead of static friction. The number that represents the friction between two surfaces is called the friction coefficient. The normal reaction force is the amount of weight being applied to one of the surfaces or objects. If no weight is being applied the normal is the weight of the object. You can find the maximum frictional force by using these two numbers in the equation F=mR where F is the max friction, m is the normal and R is the frictional coefficient.  Ice is the one exception; because different thicknesses, temperatures, and the always-fluctuating surface changes how ice behaves there have been no definitive answers as to the coefficient of ice.  This means that you can't measure how much friction you are causing between the ice and another object.  Some very famous scientists have worked on the theories and laws of friction. Leonardo Da Vinci was the first to perform experiments to measure the force of friction. He put a block on an inclined slope and measured how much weight it took to move it. These experiments lead him to the conclusion that as long as the object weighs the same the friction will be the same no matter how large it is. He also found that everything has the same friction coefficient and the number he found was 0.25. Leonhard Euler also made some important discoveries and conclusions. Using the same experimental basis as Da Vinci he conducted his own experiments. He found that when you take an already moving object it takes much less force to move then it takes to start a stationary object. He concluded that the static friction must be greater then the kinetic friction. He was the first scientist to discern between static and kinetic friction.

        The independent variable in my experiment is the type of broom head used. There are three main heads hog hair, brownie brush, and synthetic head. Hog hair brooms are made out of horse or hog hair or synthetic hairs. They are the oldest type of broom I am testing. Brownie brushes are made of thick synthetic padding covered in a synthetic material. The material is slightly rough to help create friction. This type of broom came out next. The latest type of broom is the synthetic head. This is a thin layer of foam covered by the same material as the brownie brush. I will also use another type of broom of my own creation. It is seven peaks all toped by foam and covered in synthetic very similar to the stuff that covers brownie brushes. The dependent variable is how far the rock travels. As mentioned before you can’t measure how much friction you are causing with a broom head because the coefficient of ice is not definite. Another reason is that everyone puts a different weight on the broom and as they get tired the efficiency of their sweeping decreases. Since this is the case I can’t measure the amount of friction caused which would be ideal but instead must measure how far the rock travels. The distance will be measured, in meters, from the far end of the ice to where the rock landed. This will then be converted to a measurement from where the rock started to where it landed, by mathematical computations. This was a comparative study focusing on which broom was most effective in reducing the friction between the rock and the ice surface. Each broom was made out of different materials and as such work with different effectiveness. The hog hair brooms are easy to move across the ice and because of this may cause less heating of the ice. As well they leave debris on the ice that may adversely affect the rocks speed and direction. The brownie brush is harder to push which may result in more heat. On the other hand it may also cause fatigue quickly meaning you couldn’t sweep as hard the rest of the game. Synthetic heads are somewhat easier to push creating less heat but leaving you with more energy for sweeping, a good compromise. My broom head has ridges on it. These ridges are there to create high pressure points with the same energy depletion as the synthetic heads.

        I think that my broom will work the best. Based on my research the high-pressure points will create more heat. Also the material I used was slightly more rough then the regular material perhaps causing the ice to heat up just that much faster. I think that this is an important thing to study because as of yet curling hasn’t been investigated fully using the scientific method. It has historically been “look at the guy in the other game. His sweeping works better than ours. What is he doing different?” Even though curling is an international sport science hasn’t even, really, touched it. I think curlers everywhere could benefit from this experiment.

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