Exploring the Physical World: Week 2 Blog Post

The problem that I chose to test was how different surfaces would affect the momentum of marbles.  In order to explore this problem, I first set up a ramp that would allow the marble to roll down and gain momentum.  I then measured an additional three feet for the marble to roll on the selected surface.  I placed a barrier at the end of the three feet so I knew when to stop my stopwatch. 

The first surface that I tested on was a low rise carpet.  I completed three trial runs and then found the average time, which was two seconds (see data table 1 in reference section).  Next, I moved onto a wood floor.  After completing the trial runs, I discovered that on average, the marble rolled the total distance in 1.5 seconds (see data table 1).  So far it looked as if my hypothesis, the smoother the surface the longer the marble could maintain its momentum, was correct.  To truly determine if my hypothesis was correct I wanted to test on a rougher surface.  The final test that I performed was on very rough carpet.  I was not shocked when the marble stopped completely a few feet before reaching the barrier.   See results below. 

Data Table 1: Small Marble

	Trail 1	Trial 2	Trial 3	Average
Low Rise Carpet	1.9 seconds	2.0 seconds	2.1 seconds	2 seconds
Wood Floor	1.5 seconds	1.6 seconds	1.6 seconds	1.6 seconds
Rough Carpet	Did not make it to three foot barrier

The inquiry experience made me curious about the other concepts that I had read. 

Data Table 2: Large Marble

	Trail 1	Trial 2	Trial 3	Average
Low Rise Carpet	1.8 seconds	1.7 seconds	1.8 seconds	1.8 seconds
Wood Floor	1.4 seconds	1.4 seconds	1.4 seconds	1.4 seconds
Rough Carpet	2.4 seconds	2.5 seconds	2.4 seconds	2.4 seconds

To ensure that the experiment worked out, I completed a few test runs before actually recording any data because I wanted to make sure I pushed the marble and started the clock at the same exact time.  I quickly learned that if I listened for the marble to hit the barrier, rather than looking at the marble, I received the most accurate results.

 I think this experiment is very fun for the students if you allow them to pick their surfaces that they can test on and design the steps of the experiment.  The only problems that I might encounter is bringing in different surfaces for the students to test on.  I could relate this experiment to their lives by asking them when different surfaces have affected their lives.  For example, riding a bike on ice roads verses dirt roads. 

The goal of this experiment is for my students to understand the concept of momentum and how different surfaces can affect momentum, as well as different masses.