How to use the Ratio Machine

The photo on the left shows the input link (the lower link) set with the 0” mark even with the left side of the base. The output link is marked marked with a yellow marker. The right side of the marker is lined up with the left side of base.  The right edge of the yellow marker may be considered the 0" mark for the output link.  These positions of input and output links are the starting positions for the first measurement in Experiment A.
The photo on the right shows the input pulled out 1” to the left. The output mark has moved to the left. The distance from the right side of the yellow marker to the left side of the base is 2”. This is the amount the output has moved.  Thus the result entered in the data sheet is 2".

Here are the things to do to get accurate measures with the Ratio Machine:
  1. Keep both the input link and output link horizontal when making measurements.
  2. Line up the 0” mark on the input link with the left edge of the base.
  3. Place a marker (yellow post-it in the photo above) on the output arm, its right edge even with left edge of the base, to mark the starting position.
  4. Move the input 1” to the left, so its 1” mark lines up with the left edge.
  5. Measure the distance from the right edge of the marker to the left edge of the base. In this case, 2” is the distance the output has moved. The numbered link is a good way to measure, but make sure the starting point to measure is the “0” mark, not the end of the link.
  6. Record the output data (2”) in the data table, the first column in Experiment A.

Unit Lessons