Vernier scale

Here we use the Vernier scale to analyze data from  Beads on string drop, a classroom measurement of Earth's gravitational acceleration.

There are two ways to use the resource in the classroom
 * 1) For a "hands-on" activity with scissors, the figure to the right can be copied, expanded, and printed on a sheet of paper. Students cut out the Vernier scale and measure the times associated with the rising edge of the peaks.  These correspond to times when a paperclip strikes the coffee can.
 * 2) For a less time-consuming activity, a classroom with internet access could measure the times using the images in the following section.

Both methods recover the data required to experimentally measure g.

Collecting the data from images with a Vernier scale
The first figure below shows the vernier at zero. The others verniers are aligned to the vertical dotted line (black) that represent the approximate time when a paperclip struck a coffee can. First guess the time and then hover your mouse over the figure and see if you got the right answer.