Circuit Blocks – Science Play

Teach how circuits work with this fun activity – make bulbs light up, and buzzers buzz with the press of a button, or flick of a switch!


Some things to gather for this project:

  • Alligator clips – used to connect each block to other blocks in the set. Any will work, the ones shown above were made with thicker gauge wire (16 AWG audio speaker) and larger clips for durability. The test leads you can typically get work okay, but kids tend to destroy them rather quickly.
  • LED block – made from a string of LED christmas lights. Ensure that the + and – legs are labeled properly on this one. LEDs are a diode, which means that the electricity has to flow through them the proper direction – the + has to be attached to the positive side of the battery and – to the negative side.
  • Potentiometer – this is a variable resistor. When the resistance is high, less electricity is flowing through the circuit. When lower, more. So, when the volume is turned all the way up on a speaker or speed on a motor, the resistance is lowests. When the speaker has the lowest volume or lowest speed on the motor, the resistance is at its highest through the potentiometer.
  • Piezo speaker – this is a little buzzer. Make sure for this project you are using the one that is NOT labeled “ED” – those are for a different project and Instructable I will link to. These, like the LEDs, need to be hooked up with + to positive and – to negative.
  • Battery – plain enough, this powers the whole thing. See a later step, but DO NOT short circuit the battery for too long (connect the two terminals directly to each other) or it will heat up a bunch and start smoking!
  • Motor – a little DC motor. This can be hooked up either direction – changing the polarity of how it is hooked up will change the rotational direction of the motor, a great experiment to do with these kits.
  • Knife switch – looks like something right out of Frankenstein! These switches are a way to hook up two separate components to the same battery, or just make a on/off switch that stays on/off for a component. See a further step in this Instructable for how to hook it up.
  • Momentary switch – this is a simple push button switch. When it’s depressed, it allows current to flow through the circuit. When it is not pushed, it breaks the circuit. A great setup to do is put it in line with a speaker and have the kids make Morse code.

Click HERE for the instructions


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