(dramatic music) - Heat is energy.

But most of the heat we produce from our bodies, homes, cars, and even this electric bike, (bell chiming) just dissipates into the environment.

It's a huge waste in an energy-strapped world.

(dramatic music) (dramatic music) (tool whirring) What if there was a way to efficiently turn that heat directly into electricity?

(dramatic music) A fabric that could be worn like a second skin, while helping to power our e-lifestyles?

And that is All science.

No fiction.

(bright music) (bulbs buzzing) - [Han] All of this is going to be packaged in soft, stretchy materials.

- [Narrator] Hand mounting tiny metal posts is not the most glamorous job for a highly-trained engineer.

- [Han] Yeah, you can't do this after drinking coffee.

- [Host] But these semiconductors have a superpower.

They're the vital organs of a new kind of wearable electronic device that can convert body heat into electricity.

- When I was in the high school, there was the movie called "Iron Man."

- [Host] In the movie, Tony Stark develops a suit of armor that gives him all sorts of superhuman powers.

- [Han] That's the point that I decided to do the research on wearable electronics.

I thought I could be the next Tony Stark.

(chuckling) (machine whirring) - [Host] But Han and Mohammad Malakooti don't want to use their devices to battle enemies.

They want to generate electricity.

- Our body generates heat and dissipates it to the environment.

And this idea for wearable thermoelectric devices is that let's recover that heat and use it for powering small electronics or wearable sensors.

- Think things to monitor health, like your temperature and heart rate.

So how do these thermoelectric devices convert heat to electricity?

Well, when you link certain metals together and expose one end to heat, it causes the electrons to flow towards the colder side.

That's electricity.

This phenomenon is called the Seebeck Effect.

But the cool thing is, the more you increase the difference in temperature between the two ends, say by adding a block of ice to the top here, the more electricity it makes.

But maintaining that temperature gradient is harder than you'd think.

(equipment whirring) It's so difficult, the lab has spent five years solving this and other engineering challenges.

- And we want to increase the surface area because we want to dissipate more heat on the cold side.

- [Host] They've developed stretchable 3D printed layers that insulate the cold and hot sides from each other.

- Yeah, that looks really good to me.

- [Host] And the proof of their success?

A tiny red light.

- [Malakooti] There is no energy storage device.

There is no battery, nothing.

The LED gets light up the moment you place this device on the body, converting the heat to electricity.

- [Host] It's the moment they knew they had achieved something that had never been done before.

- It was great.

(chuckling) - Powering LED with your body heat at the room temperature, this is like huge jump from the status quo.

- It feels powerful.

Okay, so.... - Is it fashionable too?

- It is very fashionable.

(both chuckling) It does feel cold.

- Yeah.

- It feels almost like you, not a piece of ice, but definitely like a piece of metal.

- Yeah, because it's dissipating heat for you.

- It could also be used in factories to make electricity from hot pipes and machinery instead of heating up the room.

- We are not trying to use more energy to do this.

So we want any kind of like waste heat, we wanted to capture it and put it into a good use.

- And if you need to wrap the converter around a hot pipe or have it bend to maintain contact with someone's skin as they move around, being flexible is very important.

(upbeat music) (screen zooming) (upbeat music) (head zooming) (Malakooti chuckling) (upbeat music) (whip cracking) (upbeat music) Han and Malakooti's thermoelectric device isn't just flexible, it's stretchy as well.

(laces whipping) (zipper zipping) (dramatic music) (whip cracking) (dramatic music) (tire rolling) (screaming) Ah!

(sighing) Well, maybe not that stretchy.

But a lab test shows just how stretchable it can be while still conducting electricity.

- Yeah, we don't want to squeeze it too hard, but let's see how far we can go.

- [Host] The setup is simple.

Clamp the device in to see how far it can stretch and still keep the electricity flowing.

- [Malakooti] Ready?

(suspenseful music) - [Host] At 150% the original length, electricity still flows easily.

(suspenseful music) 200%.

300%.

(suspenseful music) (machine beeping) The beep means no more flow.

- We lost the connection.

- Yeah.

That was almost 400% strain.

- That's more than the wearable device would ever likely need to stretch in the real world.

(gentle music) And this all works because of another feature of the new design.

Liquid wires.

Most metals are solid at temperatures comfortable to humans, but not gallium.

(gentle music) And if you mix gallium and indium together, you get something called a eutectic alloy, which means the melting point of the mix is even lower.

(alloy plopping) It's liquid at room temperature.

You can use this liquid instead of solid wires to conduct electricity.

Liquid metal wires don't break as they're stretched, they morph to fill the space.

- And we can repeat this as many times as we want.

Reshape it, reform it.

That's the beauty of having liquid conductor.

(dramatic music) - [Host] Malakooti and Han have accomplished something incredible with their innovative designs, but their devices are not going to be powering our cities anytime soon.

- [Malakooti} This is not going to address the energy crisis in the world, but as standalone self-sustainable electronics devices.

- [Host] Health monitors, weather gauges, smart kitchens, maybe even converting heat waste from electric vehicle batteries back into usable electricity.

- I kind of feel like I'm a dreamer.

Like, how can we push the boundaries?

It's really good.

Good job.

I feel like we are discovering new phenomena.

We are showing new applications.

Possibilities that is going to maybe at some point, change our lives.

- [Host] And in a world that seems to need more and more energy every day, tapping into waste heat to help power our lives is a tantalizing solution.

- [Interviewer] What would you call Iron Man if he was built from the technology you have created?

- I would say, I just want to name it with my name.

(chuckling) - Young Man.

- Yeah, Young Man.

(group laughing) Young Man.

(chuckling) - Let me close this, because I don't want to spill the beans, the beans.

(chuckling) - Too much smoke!

(group laughing) Oh my God.

It felt like was in volcano.

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You're the power that makes All Science.

No Fiction.

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(snickering) - (beeping) Nailed it.