ElectroChemistry Teaching Chamber

myminifactory

This chemistry teaching aid is designed to instruct middle school students about electrochemistry and the separation of Hydrogen and Oxygen from H2O when electricity flows through an anode to a cathode in water. This model features elements that cannot be printed using a standard plastic 3D printer. They include: two M4 machine screws, any screw will do if you modify the hole size in the FreeCad file; fourteen gauge wire with arbitrary red and black colors to demonstrate function to students; one Plastic Drinking Straw with a diameter of a quarter inch or six millimeters; and one Power Supply which can be any voltage but higher voltages produce faster reactions. The variable voltage power supply helps demonstrate electrochemistry, I used nine-volt batteries that can be daisy-chained into multiples of nine. To build this model, start by attaching the screws with wire wrapped around them to form a watertight seal. Next, insert straw sections into the top and use hot glue to secure them in place (hot glue is optional). Mix one cup of water with one teaspoon of baking powder or salt. Pour the mixture into the hole which can be done most easily by submerging the entire part in water. Fill the straws until they are full of water. Attach wires to the battery and observe how bubbles rise from the chamber into the straws. If you cover the ends of the straws with your fingers, the water level on the negative side will drop faster than the positive side demonstrating that water is split into twice as much hydrogen as oxygen. After printing, clean the part by pouring out the water and flushing it with clean water until dry and use again later. If the reaction gets too slow remove the machine screws and clean them off because oxidation on screws can slow down the reaction. The cost of printing this model is estimated to be $2 assuming twenty dollars per kilogram for filament. Screws are approximately twenty cents if using stainless steel, less expensive options are available but oxidation on the positive terminal produces oxygen gas instead of hydrogen and oxygen. Wire costs one cent and a plastic drinking straw costs two cents. Batteries cost eleven cents. The total cost is estimated to be three dollars and thirty-five cents. No commercial equivalent was found for this model.