In the momentum experiment I chose to investigate “How do different surfaces affect the momentum of marbles”. Even though I teach life science, my knowledge of general science greatly helped me in the investigation. In fact I was pretty sure of the outcome of any of the proposed questions but not sure how to test for all of them. I saw a specific challenge with working with marbles and wondered what is the best way to launch them onto different surfaces. Obviously flicking would not allow me to maintain a control speed as it is impossible to flick with the same amount of force at all times. I eventually did realize that I could use gravity and send the marble down a slope (another control) and get a constant start speed.
From this point I chose to test surfaces that were readily available in my classroom along with a rug I could easily bring in from home. I ended up testing two different carpet textures and both a textured and smooth tile. My results showed that the smoother the surface (less friction) the farther and faster the ball would roll. Ultimately I consider the experiment a success but would like to change things if I was to use this in the future with my students. For example I believe a bigger ball would allow for more variation in the test. This is because carpets would almost immediately stop the marble where a large ball could roll better over the fibers. Also more surfaces like sand, sandpaper and even ice might help make the experiment a little longer and more fun. Even adding in accelerants like olive oil or WD-40 could add a more things to try out. I think since it is an open experiment students should be able to test different ideas they have and see if they have effects on the friction of a certain surface.
Learning about friction, momentum and even the importance of keeping controls the same are all good lessons that could come out of this one experiment. I think if I were to do this with my students I would have more options for testing i.e. let them choose the type of ball and surfaces. Lastly I think that to relate this to students’ lives it would be cool to talk about sports and how soccer, golf and hockey are all affected by friction and how design of equipment and sports technologies accounts for this.
