Original Source: “iPad and Weightlessness,”” The Physics Teacher, May 2012, by Taoufik Nadji.

Now that cell phones and tablet computers have built-in accelerometers, it is natural that physics instructors would want to use them for experiments. In this article, Nadji suggests (carefully) dropping an iPad® onto an outstretched sheet held by students. Since our Graphical Analysis™ for iPad collects data from the iPad’s built-in accelerometers, we could not resist trying this experiment.

In our results, shown below, we noticed an interesting thing about dropping iPads. The acceleration is different depending on whether you drop it with the screen facing the ceiling (lots of drag) as compared with the screen facing horizontally toward the wall (very little air resistance). The air resistance shows up on the upper graph. Notice that the Z-axis acceleration is near zero at the start of the drop and then increases as air resistance becomes more important.

Here are our results:

An Apple iPad dropped with the screen facing up.
An Apple iPad dropped with the screen facing horizontally.