I bought four conductivity meters or probes. First, we went over the instructions for this lab. I had several solutions to test: vinegar, ammonia, citric acid, denatured alcohol, isopropyl alcohol, hydrogen peroxide, distilled water, tap water, and salt water. (We also tested acetone. Don't use acetone! It corroded the plastic on the conductivity meter. I should have thought of that. Instead I thought about what a good organic or covalent solution acetone is.) We designed the lab together. The lab is testing solutions for their conductivity; if it conducts it's ionic. Covalent solutions are zero with the conductivity probe or meter.
We created a data table together, too. In the data are the solutions, prediction (ionic or covalent, plus or -, charge, and ionic or covalent.) The purpose was to learn the difference between ionic and covalent solutions; one produces a charge and one does not.
The kids set up a beaker for waste solutions and one with distilled water. It's important to rinse the conductivity probe each time between measuring conductivity of each solution. We discussed cross contamination of solutions. I reminded the kids not to pour solutions back into the containers: it's possible to contaminate the entire container.
After the kids tested and recorded their results, they wrote the lab reports at the end of class and submitted them. The reports include the following: title, purpose, data table, materials, and procedures.
(Here is a similar lab. Calcium chloride is Drive Way Heat. Substitute sugar for corn sugar.)
Distilled water, denatured alcohol, isopropyl alcohol, hydrogen peroxide, and ammonia are covalent molecules. Tap water, salt water, citric acid, and vinegar are ionic compounds. Below are a number of photos.
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