A series about making electricity "visible" to students to drive resilient understanding of the basics AND giving students an authentic experience on the scientific use of models to generate testable hypotheses then design experiments to gather evidence to evaluate the model.
The series: Visible Electricity
Visible Electricity 1 - how to build a water model of a simple circuit (ready to go version available here)
coming soon...
Visible Electricity 2 - Great ideas for your lessons using the water model - generating accurate and robust understanding of circuit basics: voltage, current and resistance.
Visible Electricity 3 - Using this to teach how models are used by scientists and give students an authentic experience of the model-prediction-hypothesis-experiment-model evaluate cycle of data science.
Visible Electricity 4 - Mystery circuit simulator to "gamify" and great a rewarding challenge opportunity, connects with autonomy and competence dimensions of student motivation.
Construction details:
All the valves and black hose fittings are the "watering system" parts you can find in the garden section of a hardware.
The orange tank outlet-inlet into the upper tank are garden hose joiners (some of the cheap ones have extra holes which does not affect its intended use, but stops it being used as a tank outlet as shown here.) You need to create a soft rubber washer to seal for these - you can use rubber sheet and suitable hole punches or scissors. Make sure you buy a joiner with a central ridge against which the rubber can seal.
The risers are made from clear acrylic tubing. I sourced from a plstic supplier near me as 2.0m lengths and cut into 4 x 500mm. The clear 13mm PVC tubing (also from hardware stores) can also be used for the risers if you can't find clear acrylic tube.
The pump must be low voltage. I used a "solar" pump as most of the other pond pumps are main voltage. The relay is a standard car 12V "horn" relay and the float switch is available online or a local electronics store.
The one-way valve is critical. Without this, the water keeps draining back into the tank which causes the pump continually cut in and out even with no current flow, which ruins the model's similarity and is just a pain. This took a while to find something and making it myself was the best outcome. I used a glass marble and a zip tie curled up won't rust and stops the marble from sealing on the "on" direction. Expanded view on the right.
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