circuits in play dough | that conference 2015

10
@scichelli #thatCircuit s Facilitated by Sharon Cichelli Principal Technical Lead Headspring in Austin, Texas With thanks to Squishy Circuits University of St. Thomas http://www.stthomas.edu/squishycircuits/ Circuits In Play Dough

Upload: sharon-cichelli

Post on 19-Aug-2015

92 views

Category:

Science


0 download

TRANSCRIPT

Page 1: Circuits in Play Dough | That Conference 2015

@scichelli #thatCircuits

Facilitated by

Sharon CichelliPrincipal Technical LeadHeadspring in Austin, Texas

With thanks to

Squishy Circuits University of St. Thomas http://www.stthomas.edu/squishycircuits/

CircuitsIn Play Dough

Page 2: Circuits in Play Dough | That Conference 2015

Try this!

If the blobs touch, the LED won’t work.

Page 3: Circuits in Play Dough | That Conference 2015

Building a Circuit

• A circuit is an unbroken loop for electricity to flow through.

• Use the dough to connect each LED leg to a battery terminal.

• But don’t let the two clumps of dough touch each other. That’s a short circuit.

• Not lighting? Flip the orientation of the LED.• Nothing special about the dough; salt water

conducts electricity. (See recipe next.)

Page 4: Circuits in Play Dough | That Conference 2015

Mix:

¼ cup water

½ tablespoon vegetable oil

food coloring

Stir that into:

1 cup flour

½ cup salt

Mix it, then knead it with extra flour until it is the consistency of fun.

Conductive Play Dough

Page 5: Circuits in Play Dough | That Conference 2015

Motors!

And buzzers!That’s tin foil,

not dough.

Page 6: Circuits in Play Dough | That Conference 2015

Motors and Buzzers

• 9 volts is too much for these motors. They shut down to protect themselves.

• Each AAA battery is 1.5 volts, so two together gives 3 volts—just right.

• Use foil instead of dough. The dough has a high resistance, so it starves the motor of enough current. The foil is more conductive.

• The buzzer motor is like the one in your phone.

Page 7: Circuits in Play Dough | That Conference 2015

Watch out for short circuits

Battery terminals connected directly to each other get hot!

An LED connected directly to the battery ruins the LED.

Page 8: Circuits in Play Dough | That Conference 2015

Short Circuits

• A short circuit happenswhen current flows through a different path than the one you wanted.

• In the LED + dough circuit, if the dough blobs touch, current will go there instead of through your LED. So the LED doesn’t light.

• Foil has much less resistance than dough; foil lets more current through. LED + foil, the LED gets more current than it can handle. Permanently.

Did you fritz an LED during the workshop? Don’t sweat it; they cost pennies.

Now we’re learning about current!

Page 9: Circuits in Play Dough | That Conference 2015

Keep making circuits!

• The recipe is a few slides earlier.• Batteries, battery holders, LEDs, motors,

speakers, sensors… can be found on Amazon, eBay, Adafruit.com, Sparkfun.com, and at Fry’s and Radio Shack. (Shush. I miss the Shack.)

• These LEDs are through-hole (not itty bitty surface mount), 10mm diameter (5mm is fine), and have a forward voltage (minimum volts to work) of about 2.7 volts.

Page 10: Circuits in Play Dough | That Conference 2015

Thanks to our sponsors!