Six Rivers Charter School conductivity probe: Difference between revisions

Abstract[edit | edit source]

In Fall 2019, Six Rivers Charter School (Arcata, CA) has a conductivity probe that no longer works, is rusty, and a shock hazard if it is functional. Team Current Wave was tasked with developing a new qualitative data display that would guide students to understand the basic understanding conductivity through a liquid. Over the past semester, the team created a lighthouse probe to help not only facilitate learning with the student, but also to be engaging, aesthetically pleasing, and safe. The team was also asked to make replications that will help facilitate lab in groups of 4-5 instead of all the students sharing a single instrument.

Background[edit | edit source]

The Current Wave Conductivity Probe is a device meant to provide educational value regarding the conductivity of various liquids for the students of Six Rivers Charter School. Team Current Wave will be working directly under Professor Morago, who not only is a professor in the HSU School of Education, but works as a teacher at Six Rivers Charter School.

Problem statement and criteria[edit | edit source]

The objective of this design project is to produce a conductivity probe for the use of Six Rivers Charter School in Arcata, CA. The chemistry department will use the probe to measure the conductivity of various liquids, as well as use the probe as a teaching mechanism for students. Therefore, it is essential to design a conductivity probe that is not only accurate, but that also facilitates learning for the students, can be handled by inexperienced users without easily breaking, and can provide easy usability. The goals and criteria for this design will be determined by the clientele at Six Rivers Charter School.

The Lighthouse Conductivity Meter is a probe used for measuring the conductivity of a liquid solution. The design consists of a wooden body with a 3D printed, PLA rooftop housing. Inside is a probe block that slides along a dowel to lower two probes into a solution. The probes are connected to an electrical circuit that lights a lightbulb at the top of The Lighthouse if the solution has a enough electrolytes to carry the current across the solution. The bulb increases in brightness with increasing conductivity.

Description of final project[edit | edit source]

The Lighthouse Conductivity Meter is a probe used for measuring the conductivity of a liquid solution. The design consists of a wooden body with a 3D printed, PLA rooftop housing. Inside is a probe block that slides along a dowel to lower two probes into a solution. The probes are connected to an electrical circuit that lights a lightbulb at the top of The Lighthouse if the solution has a enough electrolytes to carry the current across the solution. The bulb increases in brightness with increasing conductivity.

Operation and Maintenance[edit | edit source]

To operate the Lighthouse Conductivity Meter, first ensure that the galvanized nail electrodes are making metal contact with the probe block. Do this with the meter unplugged to avoid any small shocks. Next, plug in the meter, and place a solution in the base. Unscrew the wingnut on the side one full turn, and use the handle to lower the electrodes into solution. After observing any luminosity, raise the probe block back up and re-tighten the wingnut. Unplug the meter, and wipe down the electrodes to minimize rust build up.

Team Current Wave has uploaded an instructional video on how to use and maintain.

Prototyping[edit | edit source]

Costs[edit | edit source]

Testing Results[edit | edit source]

Team Current Wave conducted three unique material testing experiments to select the best possible canditates for probe metal type and light.The first two eperiments were a series of oxidation reduction reactions. In the first experiment, various metal washers were submerged un a conductive solution plugged into a 9V power source for 30 minutes. Due to the large surface area to volume ratio, all the metal anodes completely oxidzed with the exception of galvanized steel. This experiment was then replicated again with metal screws of various types because they have a better surface area to volume ratio, thus, oxidize at a slower rate. Furthermore, a voltmeter was attached to the electrodes to compare the voltage at the beginning to the end because oxidation generally lowers conductive capacity. Again, every anode experienced mass reduction and change in voltage capacity with the exception of galvanized steel. Thus, galvanized steel was chosen to be the probe material for the final design. Using the newly installed galvanized steel probes, we tested a series of lights in 4 different molar solutions to find an optimal lumnosity range for a quality qualitative display. Results revealed the most reactive bulb that survived all 4 solutions was the 3.8V 0.3A light bulb for the final design.

How to build[edit | edit source]

1

Make the initial plywood and plexiglas cuts

2

Sand all plywood surfaces

3

Assemble bodies with the use of pre-drilled holes and wood screws

4

Assemble probe block -- drill holes for probes, PVC slider

5

Assemble probe block hardware and fasten wiring between washer and stainless steel cutout

6

Disassemble components and prep for paint

7

Coat components in protective, water-resistant coating of paint

8

Reassemble components with the addition of wood glue at the joints

9

Apply the light socket, light bulb and the 3-D printed roof fixture to the top of the body

Maintenance[edit | edit source]

Introduce this maintenance section.

Maintenance on The Lighthouse is expected to be at a minimum. The bulb is expected to last at least 3-5 years, after which a replacement can be plugged into the housing. There are x extra bulbs for the probes, after which a pack of ten can be bought for $5.90. Corrosion is not anticipated to be an issue, particularly with the amount of usage that the probes will get per year. If any corrosion does take place on the probes over time, a new 16 penny galvanized nail can be inserted for the cost of about $.10 each. If the probes and the bulb were replaced at most every 3 years, the yearly cost of maintenance would be $.33. No other general maintenance costs are expected to be needed for The Lighthouse.

Schedule[edit | edit source]

Daily

• After each use unplug the conductivity probe and wipe down any solution with a towel.
• When out of use, keep in a dark dry environment to avoid wear and oxidation.

Troubleshooting[edit | edit source]

This is only how to troubleshoot basic operation. For complex issues, contact Marco at mag233@humboldt.edu.

Discussion and next steps[edit | edit source]

The finished Lighthouses are sturdy, visually appealing product that will serve its purpose at Six Rivers Charter School. The Lighthouse provides a safer and more visually appealing product than what was previously used. Current Wave was pleased with the final product and are glad to have served the Arcata community. Current Wave hopes to inspires students to learn more about STEM related topics such as conductivity, oxidation and reduction reactions, and chemistry and engineering in general. The next steps for the lighthouses are for them to be painted by Six Rivers Charter School students.

Suggestions for future changes[edit | edit source]

Although the project hit all the necessary requirements for the project, there is always room for improvement. If this project were to be developed further, our team would find a more durable, cost effective, upcycled plastic substitute for the plywood body. Further more, the team would create a custom handle bent upwards for the slider so the dowel would not need to be secured at an angle for aesthetic purposes.

Page data

Authors	Marco Gudino, Kush Lightfoot Rawal, Leith, Caleb
License	CC-BY-SA-3.0
Language	English (en)
Related	0 subpages, 6 pages link here
Impact	401 page views
Created	November 18, 2019 by Marco Gudino
Modified	August 22, 2023 by StandardWikitext bot
Cite as	Marco Gudino, Kush Lightfoot Rawal, Leith, Caleb (2019–2023). "Six Rivers Charter School conductivity probe". Appropedia. Retrieved April 16, 2024.
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