I recently tried a few of Vernier’s GoDirect Wireless Sensors with my high school students and liked many of their features. Vernier technology is a popular choice for many secondary science labs.
Water Quality testing with Vernier Sensors
I tested Vernier’s wireless temperature, pH, optical dissolved oxygen, conductivity, nitrate and ammonia sensors. One group of students used the Vernier sensors for their ecocolumn data and I also tested the sensors in my fish tank.
What I liked: Students were able to easily download the Vernier Chrome extension on their Chromebook: Vernier’s Graphical Analysis 4. I made detailed directions with screenshots for the students to follow. Students had no trouble connecting the Vernier sensors. Data was very quick and easy for students. The readings were a lot faster than some of my other probes.
The optical dissolved oxygen sensor ($299) worked well and needed no calibration. The pH sensor ($89) needed calibration (as do most pH sensors and probes), but this was easy to do in Graphical Analysis. I have buffer solutions on hand, because I calibrate pH probes of varying brands almost weekly. The temperature sensor ($69) also worked well.
Vernier wireless sensors have to be charged periodically which can take some planning and a lot of plugs/ports for multiple sensors to charge. The sensors have a wired option so if the sensor is not charged, students can plug into the side of the Chromebooks. Our Chromebooks only have one plug-in port so students would have to use the sensors one at a time if not charged–but that’s typically fine for water quality testing.
Both the nitrate ($249) and ammonium ($249) sensors are harder to use. This is typical for this type of sensor of any brand. They need planning ahead of time. Both sensors need soaking in buffer solution for 30 minutes before using and often need calibration. However, I tested the sensors a week after calibrating and they held their calibration over the week of non-use. This is an improvement over sensors I used a decade ago.
Both the nitrate and ammonium sensors can inform how beneficial nitrifying bacteria are functioning. If a fish tank or aquatic chamber of an ecocolumn has low ammonia and higher nitrates, it means that there is a healthy population of bacteria for nitrification–the process of turning ammonium into nitrites and then nitrates. Ammonium is found in animal waste (like fish poop) and dead, decomposing organic matter. Ammonium is toxic to aquatic life in high amounts so a healthy population of bacteria is essential.
Older Vernier Technology with New Sensors
I have some Vernier sensors from over a decade ago that use a TI-84 Calculator interface for readings. Many of the sensors still work, but pH sensors do not have as long of a life span. So, I recently purchased some new replacement pH sensors to plug into these calculators. I purchased the Tris-Compatable pH sensor ($99), because the bottom of this pH sensor is sturdier which is good for ecocolumns. Regular pH probes tend to be rather delicate on the bottom, but these can handle more bumps with gravel in the aquatic chambers of the ecocolumns. They can also be used to measure the pH of soil using a soil slurry. I was happy to see that I can still order Vernier sensors that work with the older technology .
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