Objectif

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

Lisez-en plus au sujet de cette activité au biograph de David Schindler...

On a besoin de

• 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: