New Green Economy

Sound Waves Put Out Fires

Can sound waves bring down a city wall a la Jericho? We don’t know, we don’t think so. Can sound waves heal? We’re not sure, but certainly in some places drums, crystal bowls or metal bowls are used to create tones as a sort to affect healings. For example, for curing a hangover. But can sound waves directly applied put out a fire?

Apparently, yes.

CNET explains: it’s based on the way sound waves displace oxygen as they move through physical space — oxygen that fire feeds on. Without oxygen, no flames.

If you can suffocate a fire, you can extinguish it. Two students from George Mason University worked hard on this. They discovered that music is not suitable for manipulating fire because the sound waves it produces are inconsistent.

They found that a higher frequency sound caused the flames to vibrate, but only vibrate, not diminish.

They found that lower frequencies — 30 to 60 hertz — was the sweet spot where sound waves were able to effectively eradicate or “blow away” oxygen from the flames long enough to suffocate them. And voila, sound manipulates matter.

It’s not Jericho. But it sure is interesting.

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New Green Economy

How Nature Inspires Science

We’ve all heard that aspirin is derived from willow tree bark. Lots of things are based on similar precedents. For example, the sturdy, stretchy, sticky silks spun by spiders have inspired engineers to design pioneering medical devices such as artificial tendons and corneas.

The Nature Outlook: Biomaterials examines the many ways in which solutions created by the natural world – by spiders, mussels, geckos, lotus leaves and more – are inspiring technological imitations that surpass some of the best existing human-engineered substances.

Materials researchers are taking cues from specific plants and animals that make substances that could endow humans with superhero powers.

The scales of a pine cone are made up of two different layers, each reacting differently to changes in humidity. One layer elongates in damp conditions and the other works to resist this, causing the scales to bend. Researchers have developed smart materials with woolen spikes that are sensitive to relative humidity: the wool spikes open when the wearer sweats and close when the layer dries out.

Geckos can climb glass walls and hang from ceilings without a visible method of sticking to them. It turns out it’s the electrostatic interaction between the molecules in their feet and the molecules on a surface that keeps them pinned to their object. Hand pads, each covered in tiles with tiny silicon rubber hairs that mimic geckos’ feet, mean humans can scale walls like lizards – the more force applied to the pads, the stickier they become.

Ivy is also sticky, as it climbs walls and fences weaving vines and leaves. But unlike the gecko, ivy uses an adhesive. Ivy produces a sticky, yellowish, glue-ish liquid that lets it cling to walls and which dries into a material that can withstand forces equivalent to two million times its own weight, says Nature magazine. A new coating with industrial applications based on ivy nanoparticles might be ready soon.

Learn more about this at Nature.com. One of the best magazine subscriptions money can buy.