Assignment: Conservation of momentum in 2D collisions lab
Artifact
Reflection (Critical Thinking)
In this lab, we rolled metal marbles down a ramp, and measured how far away they landed to determine their momentum, either when rolling straight off the ramp, or when colliding at the bottom of the ramp (which was mounted on the table).
Our results had 14% error in distance and 15 degrees error in the angle of the total momentum. This was difficult to justify, especially given that the systematic error was in the opposite direction as the actual error we had in our measurements. This meant that I had to find more/better sources of error to justify our results. A few examples were the ramp angle changing, the table moving, not having a tool to take measurements at right angles, and the pendulum (used to find a point on the ground directly below the end of the ramp) being difficult to control. I also had to think about potential solutions, such as using paper clips attached to a string, which could be held up more easily.
Another example of when we had to use critical thinking was when we had to measure where each ball landed. Instead of trying to use a protractor and a ruler (which would have been difficult), we simply used two rulers and tried to align them at right angles to take a “straight” and “perpendicular” distance measurement. As mentioned before, this introduced some error as we couldn’t get a “perfect” 90-degree angle. However, I think this was far better than using a protractor (especially given how difficult it was during the Equilibrium Investigation).