List available modules

Vertically Moving Rainbow

Description:

While somewhat hard to see, the top of rainbow is shown slowly rising above the horizon. This timelapse is from the Clarion, Iowa webcamera.

Video:

YouTube Movie

Questions:

  1. Why does the rainbow appear to rise?
  2. Why don't we see the entire rainbow (full circle)? Why is only the only part of the rainbow we see in the sky?

Discussion:

The video shows a rainbow that appears to rise above the horizon. The motion is hard to notice when watching a rainbow without the help of speeding up time as in this movie. A previous module, discussed the left to right movement of a rainbow and the same material applies in this case. The vertical movement is a result of a change in solar zenith angle, which is just a fancy term for how high in the sky off the horizon the sun appears. So as the sun sets in the west, the angle changes and the rainbow will appear higher in the sky.

Links to Internet Materials:

Do you have corrections or additions to this material? Please contact us, thanks!