How to Walk Across Hot Coals

ThinkStock
ThinkStock

People have been scampering across hot coals for thousands of years. A bed of embers can exceed 1000°F, and the world’s hottest firewalk in 1997 actually topped 1750°F—the same temperature used for cremations. But with the right preparation, experts prance across them with barely a blister. Here’s how they do it.

1) Get Wood

A safe walk requires the right coals, usually cherry or maple wood. Hardwoods are excellent insulators, and they’ll protect feet from some of the heat—even when they’re aflame. (That’s why the wooden handle on a saucepan stays cool when you’re cooking.) Cherry or maple embers also glow a daunting red-orange, but they actually don’t burn as hot as other charcoals, like olive or locust woods.

2) Build a Runway

Once the fire has burnt down, rake the coals. This step makes the red-hot landing strip of doom look even more terrifying, but it will actually spread cold charcoal to the surface, adding insulation. Firewalkers also flatten the coals. Patting down a path keeps them from sinking into the sizzling embers, protecting the sensitive tops of your feet.

3) Break Out a Good Book

After making the fire, firewalkers need to kill time for about 20 minutes. Embers that still hold water can transfer heat to feet faster. Letting the coals dry means they won’t sear any soles. Then they sprinkle a thin layer of ash on top. Ash is a terrible heat conductor, and it can block some warmth radiating from the coals.

4) Just Add Water

After waiting for the bed to cool to a balmy 1000°F walkers dip their feet in some water. When liquid meets intense heat, it can form an insulating layer of steam. It’s called the leidenfrost effect, and it’s why you can snuff out a candle’s flame with two wet fingers. The moisture may act as a protective glove for feet.

5) Walk, Don’t Run

Once experts step onto the coals, they walk briskly and don’t stop. Their feet would sink into the ashpit if they run or hard-step. The lighter the stride, the less chance scorching cinders will wedge between their toes. Each step should last half a second or less.

6) Believe in Physics.

Coals may be hot, but they’re terrible at transferring heat. They have a “low thermal capacity.” That is, it takes them relatively long time to bake a walker. (It’s like sticking your hand in an oven set to 400°F. The air feels hot, but it won’t burn you instantly.) As long as they keep moving, each step will absorb very little heat from the embers.

Paris Responds to Its Public Urination Problem By Installing Open-Air Urinals

Thomas Samson, AFP/Getty Images
Thomas Samson, AFP/Getty Images

In between stops at the Louvre and the Eiffel Tower, sightseers in Paris might notice some unusual new landmarks marking the city's streets: bright red, open-air urinals. As NPR reports, the so-called "Uritrottoir" (a mashup of the French words for urinal and pavement) have been installed in response to the city's public urination problem, and residents aren't happy about it.

Peeing openly on the streets has been an unofficial tradition in the French capital since the pre-Napoleon era. Relieving oneself on city property is a fineable offense, but that hasn't stopped both tourists and locals from continuing to do it, subjecting bystanders to both the unwelcome sight and the lingering smell.

Now, Paris is taking an if-you-can't-beat-'em-join-'em approach to the issue. Uritrottoir have popped up near some of the city's most famous spots, such as Île Saint-Louis, overlooking the Seine, and Notre-Dame Cathedral. They're about the height and size of trash cans, with a receptacle that's meant to catch pee, not litter. Inside the Uritrottoir, straw and other composting materials absorb the urine and its odors, eventually breaking down into a compost that will feed the plants growing from the top of the box. A conspicuous sign of a man peeing posted above the urinal lets passersby know exactly what the contraption is for.

The built-in planters are meant to present the public urinals as something beautiful and functional, but many of the people who have to look at them every day aren't buying it. Fabienne Bonnat, a local art gallery owner, told CBC Radio, "It's an open door to exhibitionism. Who likes to see that?"

Another Île Saint-Louis gallery owner, who didn't wish to be named, told Reuters, “We’re told we have to accept this but this is absolutely unacceptable. It’s destroying the legacy of the island. Can’t people behave?"

The first three toilets were installed in March with a fourth appearing in July. The city has plans to add a fifth urinal, despite the uproar they've already caused.

[h/t NPR]

After Seven Years, Melbourne Has Been Displaced as the World's Most Liveable City

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iStock

We should all move to Vienna. That's what the Economist Intelligence Unit recommends: In a new report, it ranked Austria's capital as the world's most liveable city. With a score of 99.1 out of 100, Vienna beat out Melbourne for the top spot, which the Australian city had held onto for the past seven consecutive years. This is the City of Music's first time being number one.

The survey ranks 140 cities worldwide based on five categories: stability (including crime and terrorism); healthcare; culture and environment (including level of censorship, temperature, and cultural offerings); education; and infrastructure (including public transportation, housing, energy, and water). Overall, there were improvements in safety and stability this year for the countries surveyed.

Vienna scored a perfect 100 in four out of five categories. The only area in which the city could use a tiny bit of improvement is in culture and environment—though its 96.3 score is still pretty impressive.

The cities that scored best on the list tend to be mid-sized with low population densities and located in wealthy countries. The world's biggest urban centers, such as New York, London, and Paris, may be popular places to live for their unbeatable food and culture, but high levels of crime, congestion, and public transportation issues make quality of life less desirable and drag them down in the rankings.

The top 10 most liveable cities are:

1. Vienna, Austria
2. Melbourne, Australia
3. Osaka, Japan
4. Calgary, Canada
5. Sydney, Australia
6. Vancouver, Canada
7. Toronto, Canada
8. Tokyo, Japan
9. Copenhagen, Denmark
10. Adelaide, Australia

And here are the 10 least liveable cities:

131. Dakar, Senegal
132. Algiers, Algeria
133. Douala, Cameroon
134. Tripoli, Libya
135. Harare, Zimbabwe
136. Port Moresby, Papua New Guinea
137. Karachi, Pakistan
138. Lagos, Nigeria
139. Dhaka, Bangladesh
140. Damascus, Syria

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