Many children find difficulty studying

physics. They find it difficult to imagine what the textbook is really talking about. Electric circuits are one of the typical subject kids find difficulty understanding. Parallel resistors are definitely not something to be familiar with.

Our goal is to make something that can give insight to how those circuits work. By the flow of water, spinning waterwheel, and with something one can really make and play. And we did it! Here are some steps we would like to introduce.

Step 1: Step 1 : Tools and Materials

3-D printer

Laser cutter/acrylic panel cutter

Tube(8mm, 12mm)& tube connections & switch

Waterproof glue


Acrylic panel (one big and the other small)

Water bowl

Water pump



Plastic bottle

Clips (3 EA)

Step 2: Step 2 : Real Circuits Vs Pipe It!

Electrons ; water

Current ; flow of current

Lightbulb : water wheel

Wire : tube

Voltage source : water pressure + water pump

We chose water molecule for the representation for the electrons. Water is similar to electrons in the aspect of flow, but safe to play with. As we were aiming for a toy that kids could play with, it is very important for it to be safe

Current is defined as quantity of electric charge passed in a second- we saw it could be seen as flow of water

Light bulb in real circuits convert the energy from electric energy to light(Heat) energy. Waterwheel can represent the Lightbulbs in the aspect of converting energy

Wires allow the electrons(current) to flow- tubes allow water to.

Voltage source provides constant voltage to the circuit. By providing a constant depth for your water bottle, it can give constant water pressure, representing the voltage source.

Step 3: Step 3 : Modeling With 3d Printer & Printing It Out

Thing we made with the 3d printer:

1. Waterwheel

2. Housing for the waterwheel

3. Resistors

Waterwheels and the housing which can help them to smoothly rotate was designed and printed by 3d printer

For waterwheel, we found a model at http://www.thingiverse.com/thing:7715 and downscaled it to half.(see 1st, 2nd pictures) We downscaled it so that it is sufficiently small to fit in to our kit. But when you downscale it, its groove doesn’t fit each other well enough so we recommend you to design your own waterwheel. Our brief example is as follows.(see 3rd, 4th pictures)

Here is our design for the housing.(see 5th, 6th pictures) When you design the whole house in one scheme, 3-d printers automatically put support which was quiet hard to get rid of. As a result, we divided it to four parts; bottom, top, axis, and the pointer. If the bottom of the housing is flat, we found that the remaining water in the housing would not procced easily. Also, we found that we would need threshold to prevent the water from overflowing. To make the waterwheel rotates clockwise, water hole in the top part is a bit right sided. We also made the axis for the waterwheel by 3D printer, but since it is too thin, the printed material wasn’t successful and very fragile. So, we replaced it with metal wire. Next we attached a pointer (We colored it so that its angular speed can easily be seen) in front of the waterwheel, with our project name carved. For the last, we cut acrylic panel to cover the front of the house. The final version of it is like 7th picture

Resistors in real circuit work as energy consumer. We printed out the resistor so that it could slow down the velocity of the water in constant pressure - so that it could reduce the kinetic energy of the flowing water

We designed two types of resistors. First one is designed to have multi floors.(see 8th picture) After printing it, we covered it with acrylic panel so that the inside can be easily observed. We used glue gun to attach the two so, the final version of it doesn’t look neat since gluing them neatly was a delicate work. Our second version is designed to have twisted path inside of it.(see picture 9th, 10th pictures) It is efficient in the aspect of size and doesn’t need much gluing. You can make it half-transparent by printing with SLS type 3D printer.

Step 4: Step 4 : Making the Kit

First for the wire, we cut the tubes in

similar sizes. It would allow the parallel tubes have similar length in order to prevent tilting of horizontal tubes connecting the parallel tubes.

To provide constant water pressure, we should make sure that the depth of the water stays unchanged. First, we got the water pump which provides enough water to the bottle. Then we connected the wire on the bottom of the bottle to provide the water pressure to the circuit. Finally, we connected another wire with a bigger width to provide a path for the abundant water above the desired depth to flow away, making the depth constant.(see 1st picture) To make the different voltage levels, we made another bottle with different desired depth.

We covered the whole panel with Velcro. Then, we attached the corresponding Velcro on the back of the printed parts and connections so that they could be easily stuck to the panel.

Also, we printed the support for the panel, on which we put nonslip mat. As a decoration, we printed out project name and also attached on the panel(see 2nd picture)

For the tubes, as we thought putting a Velcro on every one of them would make the construction of circuit hard, we made a 3-d printed pocket that could hold the tubes and stuck it the panel.(see 3rd picture) Now all the components have Velcro on the back, nice and easy to carry around in a grab

Step 5: There Are Some Examples That Might Be Made Using the Kit

1. The first two figure represent the real circuit that corresponds to the structure on the right. It has a voltage source, a switch, a lightbulb, and a resistor. You can use different resistors.

2. This is a bit complex model than the first one. It has two resistors connected in series. It’s waterwheel spins slowly than the first one

3. The two resistors are now connected in parallel. By turning off the switch, you can compare it with the 1st model, which had one resistor. This model shows how current flows to different resistors connected parallel. Also by using the switch, you can tell what might Happen in real circuits having switches

4. 4th model is similar to the 3rd one except for the location of the waterwheel. This model shows the total current of the circuit with the parallel resistors.

videos corresponding to each circuits are uploaded(mp4 files)

<p>I have always thought that this would be a good way to visualize circuits. I am glad that someone actually made it.</p>

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