It makes for some pretty dramatic footage, but why does it happen?
The magic of microwaves
Unlike your stove top that applies heat directly to a pan, microwaves heat food by generating kinetic energy. It starts out with electromagnetic radiation that’s used to shift water molecules, creating vibrations that spread through the food as the plate rotates (and FYI, if you’ve been microwaving food in the middle of the plate, you’ve been doing it wrong).
“Microwaves are produced inside the oven by an electron tube called a magnetron,” explains the US Food and Drug Administration. “The microwaves are reflected within the metal interior of the oven where they are absorbed by food.”
“Microwaves cause water molecules in food to vibrate, producing heat that cooks the food. That’s why foods that are high in water content, like fresh vegetables, can be cooked more quickly than other foods.”
Why do microwaved eggs explode?
Microwaved eggs explode because of the way microwaves heat up food unevenly. As we mentioned, the heat is generated through jiggling water molecules, but that water isn’t necessarily evenly spread throughout whatever it is you’re trying to heat up (this is why many microwave meals recommend you stir mid-heating).
Microwaving high-water-content foods can result in little pockets that start heating up much faster than the rest of it. In eggs, investigations have suggested that the yolk may heat up even faster than water, creating super-heated pockets that can reach well above boiling point while the egg remains intact. That is, until it doesn’t.
Eggs can remain intact throughout all of this because the membrane and shell trap the steam generated in their center. Pressure builds until a disturbance like a knife (or a bite) comes along and finally releases that pressure, creating a searing-hot explosion that can also be pretty loud.
Going out with a “bang”
At the 174th Meeting of the Acoustical Society of America, Anthony Nash and Lauren von Blohn, from Charles M. Salter Associates, presented their research “Sound pressures generated by exploding eggs”. It followed the testimony of a plaintiff who alleged they’d suffered severe burns and hearing damage at a restaurant after a microwaved hard-boiled egg exploded in their mouth.
“We needed to quantify the peak sound pressures from an exploding egg so we could compare it to hearing damage risk criteria,” said Nash in a statement. “At one foot away, the peak sound pressure levels from microwaved eggs covered a wide range from 86 up to 133 decibels.”
“Only 30% of the tested eggs survived the microwave heating cycle and exploded when pierced by a sharp object. On a statistical basis, the likelihood of an egg exploding and damaging someone’s hearing is quite remote. It’s a little bit like playing egg roulette.”
Egg roulette. Hearing damage or no, it doesn’t really sound like something you want to have happening under your nostrils, does it?
Source Link: Why Do Microwaved Eggs Explode When You Bite Into Them?
