I just put out a new video showing an alternative means for measuring conductivity for those who do not have a conductivity meter. This procedure applies to Lab 1-4 (Solution Chemistry of Natural Waters). While making this video I first tried using a 9-volt battery to provide the current, but the amperage reading kept dropping. I learned later that this happens when the voltage drops. This is often a problem with zinc batteries that are not fresh. Only then I decided to switch to a lead acid battery because it provides a more reliable voltage.