Experiment objective

You can easily make a sechi disk to measure water turbity -- an indication of water quality in terms of its clarity.

Read more background about this activity in David Schindler's bio...

You need

  • 1. a 20cm-diameter, 6mm-thick Plexiglas disk with a hole in the middle (this may be cut from a square sheet of Plexiglas)
  • 2. metal disk with a hole in the middle (to weigh down Secchi disk)
  • 3. an eyebolt with nuts and washers to fit it
  • 4. rope or cord- try to avoid cotton, as it stretches
  • 5. waterproof black and white paint

 Instructions and materials can be found at the following places:


Carleton University Science Education Resource Centre
Math in Science Centre (pdf file)