Day 86: Spinny Chairs.Posted: January 24, 2013
Today we started by figuring out how an accelerometer in a labquest works, then confirming the directions and signs for the x,y, and z axes. Then I had students predict what the x, y, and z acceleration graphs would look like, and we quickly shared our thoughts. Many groups had something like below;
One class had a particularly interesting discussion about how they would expect the graphs to be sinusoidal if the labquest were maintaining a constant orientation (ie, if the x axis was always pointing west, rather than our method which was to have the x axis always pointing tangential to the circle, so it changes direction in an Earth reference frame) vs our method.
In the end, we spun, and we got some pretty decent data showing the y axis had negative acceleration (when the screen was pointing up), showing the acceleration was toward the center of the circle. They also picked up quickly that the speed of rotation seemed to have an effect; we will investigate that tomorrow.