how do you find the salinity of pond water from a pond water sample?

Answer 1

THere is a special piece of equipment to do this, but to get a rough reading, use a multimeter - one of those gadgets that electricians use that measures volts, amps and ohms. Set up a series of standards using distilled water, and dw with various concentrations of salt in it. Make like a little chart of the difference in conductivity between the different levels of salt in your standards. Then check the conductivity of the pond water and compare it to the standard chart you made.

Conductivity doesnt directly measure the NaCl value, but since NaCl is pretty likely to be by far the most common electrolyte in the pond water, it gives a fair estimate.

Answer 2

You can do this through tests like chemoanalysis.