Don’t try this at home: TEDxTempleU speaker Mike Zdilla pours up a liquid nitrogen cocktail to demonstrate the Leidenfrost effect, a phenomenon that occurs when a liquid comes into contact with a surface that is much hotter than the liquid’s boiling point: in this case, liquid nitrogen and Professor Zdilla’s mouth.

Says Zdilla in his talk:

My tongue, as far as the liquid nitrogen is concerned, is incredibly hot. So as soon as it comes close — before it even touches me — it effectively is instantly vaporized into this barrier gas that protects me from the liquid nitrogen … So the liquid nitrogen doesn’t ever really actually touch my tongue. 

Zdilla first tried this wild vapor-breathing as a way to explain the chemistry behind harnessing renewable energy sources — such as hydroelectric, wind, geothermal, and solar — and look for ways to make them work for us. Here’s what he discovered:

Building floating neighborhoods in Boston: Brian Healy at TEDxBoston

Above, renderings of Floatyard, a proposed floating housing complex in the Boston Harbor

After Hurricane Sandy wreaked havoc on communities on the United States’ East Coast, many concerns about the longevity and durability of coastline architecture came to rise. Fear of future extreme weather events, rising sea levels, and changing geography have made architects like TEDxBoston speaker Brian Healy re-think how they are looking at building near water.

At TEDxBoston, Healy spoke about his vision for creating a floating, residential neighborhood in the Boston Harbor, a plan he calls Floatyard.

Floatyard is imagined as a floating housing complex comprised of “three stories of living units [arranged] along the four sides of a central courtyard,” reports the Boston Globe. Units would come in different shapes and sizes, with the courtyard providing a communal space for residents, including a garden, playground, and meeting space. Shops and recreation would take up some of the first floor, while the roof plays host to gardens and solar panels. Additional energy for the complex would be harvested from the movement of the building in the surrounding tides.

In his talk at
TEDxBoston, Healy explains the Floatyard project and provides context for his plans. From his talk:

Water is essential to us: to our bodies, to the planet, to everything. And we naturally gravitate and want to live [by water]. But [Hurricane] Sandy reminded us of the challenges of living or investing along the coastline…We’re reminded by the predictions of the rising sea and the potential flooding [of coastal cities] that we need to re-think how we inhabit the coast…

What if [a building] floats?…We found technology in Europe, particularly in Holland and Germany: lightweight, concrete floating tubes that we could utilize…We got excited about the idea of thinking about new buildings being floated — shipped — up and down the coast…

For more on Floatyard and designing future cities, watch Healy’s entire talk below:

(Photos: Perkins + Will Architecture)

Photos: The Laddermill team testing their new power-kites. See a full video here.

Want renewable power? Go fly a kite.

"Today, wind turbines are the cornerstones for the transition from fossil fuels to renewable energy provision," says Roland Schmehl in his talk at TEDxDelft in the Netherlands. But they are not without their problems, he admits. There’s the threat to wildlife, the noise, the lack of mobility.

So, he’s proposed a solution: kites.

Above: Roland’s talk — “Finally, kites have grown up.”

As a member of the Applied Sustainable Science, Engineering and Technology (ASSET) Institute at Delft University of Technology, he is a part of the Laddermill project — an effort to create giant kites that serpentine the sky to collect kilowatts of power in the double digits, if not more.

A prototype of the Laddermill collected 10 kilowatts of power on a test run, “enough electricity to power 10 family homes,” according to The Guardian, and it has been predicted that a collection of Laddermill kites could possibly capture 100 megawatts of power — enough to power 100,000 homes.

"The bigger you build a [tower-based wind] turbine," Roland says in his talk, "the more efficient you can make it… the higher you reach with the turbines, the higher the energy density that you can harvest. But there is obviously a limit. Although we’ve built turbines that are approaching the wingspan of an Airbus 380 — there is a limit. It is a structural limit. We simply cannot build tower-based turbines that can actually reach into several hundred meter altitudes."

This is where the kite comes in:

"The [tip], the last 25% of [a wind turbine] rotor blade actually makes more than 50% of the energy," he says. "So why don’t we decouple the rotor blade from the hub and actually move it — as a free-flying wing — into the air?"

"The kite system can adapt itself to the altitude where the actual wind power is — so if there is little wind at the ground, we just fly higher, where the wind is typically stronger. If the wind is too strong, we can go lower again…

We put the generator onto the ground; we connect that with a very strong and lightweight tether, which actually converts the traction force of the wing — transmits that to the generator — to convert to electricity.

[And] it can be used, for example, for remote applications: development areas, disaster areas, all these places where you need energy quickly and you don’t have oil — or fuel.”

So, the next time you go to fly a kite, remember its power — and watch more TEDxDelft talks via their YouTube playlist.