Sóc partidària de l'educació pràctica. Però amb les eines adients. Si he d'ensenyar electrònica a la meva filla, no li donaré pas una soldadora. Així mateix, els taulers de prototips resulten frustrants per a les seves manetes. Amb el meu magnífic alumne Sam vam decidir pensar en la cosa més flexible possible, la plastilina. I ens vam passar l'estiu provant diferents receptes per a fer-ne. Receptes que segur que li sonen a qualsevol que hagi fet plastilina casolana, amb ingredients normals que segur que teniu a la cuina. En tenim dues preferides: una amb aquests ingredients i l'altra posant-hi sucre en lloc de sal. I són genials. Es poden fer escultures molt bones.
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.
Però el més guai és quan les ajuntem i veiem que la plastilina molt salada condueix l'electricitat. No és cap novetat. La plastilina normal que es compra condueix l'electricitat i fa anys que els mestres de física la fan servir. Però la plastilina casolana té la meitat de resistència que la plastilina comercial. I la pasta de sucre? És 150 vegades més resistent al corrent que la de sal. I això què vol dir? Vol dir que ajuntant-les obtenim circuits que els ditets més petits i creatius poden construir tots sols.
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.
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Us en faré una petita demostració. Agafo la plastilina salada, segurament com la que feieu de petits, la connecto... és una bateria normal de dos contactes, es pot comprar al Radio Shack i gairebé a tot arreu, i ara podem fer llum. I si algú de vosaltres és enginyer elèctric, també podem crear un curtcircuit. Si els ajunto, s'apaga la llum. Exacte, el corrent vol travessar la plastilina, no el LED. Si els separo, tornem a tenir llum. I ara amb la pasta de sucre, que no vol conduir l'electricitat. Fa com una paret. Si la poso enmig, tota la pasta està en contacte, però si hi torno a ficar el llum, tenim llum. I fins i tot podria donar-hi una mica de moviment. Per a fer una cua giratòria, s'agafa un motor, s'hi posa plastilina, la hi enganxem bé, i ja ho tenim.
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.
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I a partir del més bàsic es poden fer circuits una mica més complicats. D'aquest en diem "circuit de sushi". Els encanta als nens. El torno a connectar i ja estaríem parlant de circuits en paral·lel i en sèrie. Hi puc connectar molts llums. I estaríem parlant de coses com la càrrega elèctrica. I si hi posem molts llums i hi afegim un motor? Llum tènue. S'hi poden afegir microprocessadors i que això fes d'entrada i crear música esponjosa com aquesta. Es poden fer circuits en paral·lel i en sèrie per als nens.
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.
I tot això a la cuina de casa. De fet, hem mirat de convertir-la en un laboratori d'electrònica. Ho tenim tot penjat a un lloc web. Les receptes casolanes, alguns vídeos. Els podeu fer vosaltres mateixos. És molt divertit perquè així veiem fins on es pot arribar: una mare de Utah que els feia servir amb els fills o un científic del Regne Unit, o uns programadors de Hawaii.
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.
Us convido a agafar un xic de plastilina, sal i sucre i us poseu a jugar. Normalment no veiem la cuina com un laboratori d'electrònica o els nens com enginyers, però potser ho hauríem de fer.
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.
Que vagi bé i gràcies.
Have fun. Thank you.
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