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  • I'm a huge believer in hands-on education.

  • But you have to have the right tools.

  • If I'm going to teach my daughter about electronics,

  • I'm not going to give her a soldering iron.

  • And similarly, she finds prototyping boards

  • really frustrating for her little hands.

  • So my wonderful student Sam and I

  • decided to look at the most tangible thing we could think of:

  • Play-Doh.

  • And so we spent a summer

  • looking at different Play-Doh recipes.

  • And these recipes probably look really familiar

  • to any of you who have made homemade play-dough --

  • pretty standard ingredients you probably have in your kitchen.

  • We have two favorite recipes --

  • one that has these ingredients

  • and a second that had sugar instead of salt.

  • And they're great. We can make great little sculptures with these.

  • But the really cool thing about them is when we put them together.

  • You see that really salty Play-Doh?

  • Well, it conducts electricity.

  • And this is nothing new.

  • It turns out that regular Play-Doh that you buy at the store conducts electricity,

  • and high school physics teachers have used that for years.

  • But our homemade play-dough

  • actually has half the resistance of commercial Play-Doh.

  • And that sugar dough?

  • Well it's 150 times more resistant to electric current

  • than that salt dough.

  • So what does that mean?

  • Well it means if you them together you suddenly have circuits --

  • circuits that the most creative, tiny, little hands

  • can build on their own.

  • (Applause)

  • And so I want to do a little demo for you.

  • So if I take this salt dough,

  • again, it's like the play-dough you probably made as kids,

  • and I plug it in --

  • it's a two-lead battery pack, simple battery pack,

  • you can buy them at Radio Shack

  • and pretty much anywhere else --

  • we can actually then

  • light things up.

  • But if any of you have studied electrical engineering,

  • we can also create a short circuit.

  • If I push these together, the light turns off.

  • Right, the current wants to run through the play-dough, not through that LED.

  • If I separate them again, I have some light.

  • Well now if I take that sugar dough,

  • the sugar dough doesn't want to conduct electricity.

  • It's like a wall to the electricity.

  • If I place that between, now all the dough is touching,

  • but if I stick that light back in,

  • I have light.

  • In fact, I could even add some movement to my sculptures.

  • If I want a spinning tail, let's grab a motor,

  • put some play-dough on it, stick it on

  • and we have spinning.

  • (Applause)

  • And once you have the basics,

  • we can make a slightly more complicated circuit.

  • We call this our sushi circuit. It's very popular with kids.

  • I plug in again the power to it.

  • And now I can start talking about parallel and series circuits.

  • I can start plugging in lots of lights.

  • And we can start talking about things like electrical load.

  • What happens if I put in lots of lights

  • and then add a motor?

  • It'll dim.

  • We can even add microprocessors

  • and have this as an input

  • and create squishy sound music that we've done.

  • You could do parallel and series circuits

  • for kids using this.

  • So this is all in your home kitchen.

  • We've actually tried to turn it into an electrical engineering lab.

  • We have a website, it's all there. These are the home recipes.

  • We've got some videos. You can make them yourselves.

  • And it's been really fun since we put them up to see where these have gone.

  • We've had a mom in Utah who used them with her kids,

  • to a science researcher in the U.K.,

  • and curriculum developers in Hawaii.

  • So I would encourage you all to grab some Play-Doh,

  • grab some salt, grab some sugar and start playing.

  • We don't usually think of our kitchen as an electrical engineering lab

  • or little kids as circuit designers,

  • but maybe we should.

  • Have fun. Thank you.

  • (Applause)

I'm a huge believer in hands-on education.

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