Here I am in a new science course and this time I am exploring physics. I was give the task of exploring one of several scientific inquiries. I chose the questions “How do different surfaces affect the momentum of marbles?” I chose this question because it lines up with my own state’s objectives for eighth grade science. Under “inquiry”, students are to “design, conduct, and analyze conclusions from an investigation that includes using experimental controls” and to “recognize Newton’s Three Laws of Motion and identify a situation that illustrate each law” (Mississippi Science Frameworks, 2008). With my eighth grade students in mind, this seemed to be a great question to explore.
I decided to use the blue marbles provided in my science kit. I sat at my dining room table and marked a starting position. Next, I set up the large marble and gave it a slight push. The marble rolled off the table. I measured from my starting point up to the end of the table, which came to 141.5 cm. I repeated this four more times for a total of five trials. Each time, the large marble fell off the table. I repeated the process with the smaller marble and achieved the same results. Next, I decided to try it on the floor in our hallway. The surface is smooth, similar to the tabletop’s surface. I completed five trials using each marble. In all trials, the marble eventually came to a stop. The average distance traveled for the large marble was 562 cm. The average distance traveled for the small marble was 604.7 cm.
I returned to my kitchen table. This time I rolled the marble on a linen place mat. I measured the distance travelled. Both marbles stopped without rolling off the table. In fact, they never rolled off the place mat. The average distance travelled for the large marble was 31.6 cm. The average distance travelled by the small marble on the place mat was 30.7 cm. I noticed that the linen place mat was not as smooth a surface as the table. The linen place mat provided more friction for both marbles.
For my final surface, I used a large plush towel. The average distance travelled by the large marble was 18.4 cm. The average distance travelled by the small marble was 13.3 cm. It was clear in my observations that the towel provided the most friction of all three surfaces. This lab was a perfect example of Newton’s First Law of Motion, also referred to as the law of inertia. Newton’s First Law of Motion states, “An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force (The Physics Classroom, 2011).
Because I had completed inquiry lessons on friction before, my results came as no surprise. However, the lesson was not wasted. I still learned from it. I could see expanding the surfaces I used. I would like to explore other surfaces such as grass, a dirt road, carpet, marble, etc. I also could foresee the parameters needed before doing this experiment with my students.
If there were any challenges in this guided inquiry, it was my starting surface. The table was too short. I had to move to the floor for the first part of my experiment. This would need to be a consideration when used in the classroom, as well. If I did this activity in the classroom, I would place some meter sticks on the floor to create lanes. This would ensure that marbles do not roll under desks and filing cabinets. I would also need to have enough space for several small groups to conduct their explorations.
I could envision using this activity as an introductory lesson to Newton’s First Law of Motion. I would like to tie it in to how friction helps us in routine activities. For example, when I have seen large trucks unloading their content at a large store, they have a special set up to make the work easier. They use a plank that looks like a ladder but instead of rungs, it uses poles that move. The plank stretches from the truck to the dock. All the workers must do is push the boxes across the plank to unload. The poles roll and provide little friction. The boxes glide across the plank and a worker will load them onto a pallet. The planks make the unloading process much easier than it would be without the device.
I would continue the lesson on friction by having my students design their own planks. Students could use items like cardboard tubes from toilet paper and paper towel rolls, pvc pipe, etc. By designing their own planks, I would be utilizing the engineering design process in a lesson that has relevance to the real world. It is this type of activity that can leave a positive, lasting impression on students.
Stop and consider that the plank design lesson stemmed from a science inquiry activity involving marbles, friction and the law of inertia. As science educators, we have to be willing to delve in a little deeper to find these meaningful activities. These activities must line up with our national and state standards. The activities should also encourage STEM education. Students need opportunities to problem-solve, explore, discover, and engage in situations that need solutions (Fioriello, 2011). It is these kinds of lessons that scientists, technicians, engineers, and mathematicians are born.
References:
Alsworth, C., Baird, C., Beasley, R., Bell, C., Billiongsley, T., Bishop, V., …Anjanete, Z. (2008). 2010 Mississippi science framework. Mississippi State Board of Education. 51-56.
Fioreiello, P. (2011) Understanding the basics of STEM. K-12 Education Practices & Issues. Retrieved from: http://drpfconsults.com/understanding-the-basics-of-stem-education/
The Physics Classroom, (2011). Newton’s first law of motion. The Physics Classroom retrieved from: http://www.physicsclassroom.com/Class/newtlaws/u2l1a.cfm
