by Robin Andrews
photo credit: Boing! This is something known as the Leidenfrost effect. Tito4re via YouTube
As far as gastronomic creations are concerned, they perhaps don’t get any stranger than combining a McDonald’s Big Mac burger with molten copper. This is precisely what YouTube user Tito4re has done, resulting in a cacophony of noise, fire and one fairly charred burger.
Initially, however, the broiling copper seems to bounce off the venerable fast food item, which some have interpreted as a sign of the Big Mac’s almost otherworldly properties. If even a fluid at 1,085 degrees Celsius (1,984 degrees Fahrenheit) can’t quickly break down the burger, one may ask, what horrible effect is it having on a person’s digestive system?
This phenomenon is actually known as the Leidenfrost effect, and it’s not solely related to copper, but any fluid that encounters another object that is at a radically different temperature.
If lava suddenly erupts into water, the temperature difference causes the water immediately surrounding it to turn into a vapor. This vapor film isolates the hot lava from the rest of the water, preventing the liquid from suddenly boiling. Eventually, the vapor film collapses as the temperature between the lava and the water equalize – sometimes with explosive results.
A vapor film developing around a red hot nickel ball in water. carsandwater via YouTube
In the case of the molten copper, it impacts the surface of the far colder and somewhat moist burger, and a vapor film develops suddenly. This causes the drops of copper to bounce back upwards, causing it to fall harmlessly away. Pouring near-boiling water onto the burger would not have the same effect; the temperature difference between it and the burger wouldn’t be high enough to initiate the Leidenfrost effect.
Rumors surrounding the strange chemicals that may comprise some of McDonald’s food have been bandied about before. One burger was left exposed to the elements for 30 days and remained relatively intact, particularly in comparison to other fast food chain burgers. The Big Mac certainly contains some preservatives, but in this case, its prolonged survival is thanks to the fact that the thin beef patty didn’t retain much moisture, a vital component required for mold to develop.
In any case, contrary to what you may read online, Big Macs aren’t imbued with terrifying magic powers, nor are they indestructible and indigestible. This molten copper experiment, although seriously cool, is another example of how the science behind it can be lost in the media frenzy.