Analyzing the motion of a marble down a ramp
Summary
This lab activity involves rolling a marble down a ramp where the students can investigate constant acceleration motion. The students mark off the position of the marble after 1 s, 2, s, 3 s, and 4 s. This allows them to see the difference in displacement for each second the marble has traveled. The students then make a position vs. time graph and a velocity vs. time graph in order to investigate the change in motion.
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Learning Goals
1. To understand the difference between position and displacement
2. To calculate the velocity as the change in position divided by the change in time
3. To understand position vs. time and velocity vs. time graphs and to know that the slope of a position vs. time graph is the velocity and the slope of the velocity vs. time graph is the acceleration.
4. To develop a conceptual understanding of the difference between position, displacement, velocity, and acceleration.
2. To calculate the velocity as the change in position divided by the change in time
3. To understand position vs. time and velocity vs. time graphs and to know that the slope of a position vs. time graph is the velocity and the slope of the velocity vs. time graph is the acceleration.
4. To develop a conceptual understanding of the difference between position, displacement, velocity, and acceleration.
Context for Use
I use this lab activity in a 12th grade high school physics course after we have gone through the definitions and equations for the topics of position, displacement, velocity, and acceleration. This lab can easily be completed during a 50 minute class period.
Description and Teaching Materials
In this lab I use plastic corner protectors (purchased from a hardware store) for the ramp and then pieces of clay or Play-Doh as a way to adjust and hold the ramp. Using dry erase markers the students mark the starting point of the marble and then the position of the marble after 1, 2, 3, and 4 seconds. This allows them to see how the marble undergoes a greater change in position for the same time period as it is traveling down the ramp. The students then make position vs. time graphs and velocity vs. time graphs as a way to see the marble is always speeding up. I also have the students find the slope of each of the graphs so they can have another way to understand how position, velocity, and acceleration are related to each other.
Analyzing the motion of a marble down a ramp (Microsoft Word 32kB Aug3 09)
Analyzing the motion of a marble down a ramp (Microsoft Word 32kB Aug3 09)
Teaching Notes and Tips
I find this activity very straight forward and without many safety concerns. I think this activity is most useful to students if done very early on in their studies of motion and is a gives a good visual model to think of in order to relate position, velocity, and acceleration.
Assessment
The students need to fill out a worksheet as they are completing the lab where they record their data, make graphs and answer some basic questions. Then once the activity is completed we have a class discussion to go over the concepts involved and to check for understanding.
Standards
9.2.2.2.2