When I was in seventh grade our science teacher left a black iron skillet on the sidewalk in front of our school. The temperature reached 130 degrees F according to the thermometer in the skillet. We were able to fry an egg in it. Air temperature at the time was about 109 degrees F.
This question comes from the saying “It’s so hot you could fry an egg on the sidewalk!” How many kids, hearing it, actually try? Most likely they end up with a mess resembling scrambled eggs more than one sunny-side up. So what’s the problem?
An egg needs a temperature of 158°F to become firm. In order to cook, proteins in the egg must denature (modify), then coagulate, and that won’t happen until the temperature rises enough to start and maintain the process.
The sidewalk presents several challenges to this. According to an experiment reported in Robert Wolke’s book, What Einstein Told His Cook: Kitchen Science Explained, sidewalk temperatures can vary depending on the composition of the sidewalk, whether it is in direct sunlight, and of course, the air temperature. Dark objects absorb more light, so blacktop paving would be hotter than concrete. More often than not, sidewalks are concrete. Wolke found that a hot sidewalk might only get up to 145°F. Once you crack the egg onto the sidewalk, the egg cools the sidewalk slightly. Pavement of any kind is a poor conductor of heat, so lacking an additional heat source from below or from the side, the egg will not cook evenly.
Still, the idea of cooking an egg on a sidewalk won’t die. It is so intriguing that the city of Oatman, Arizona, hosts an annual Solar Egg Frying Contest on the 4th of July. Contestants get 15 minutes to make an attempt using solar (sun) power alone. Oatman judges, however, do allow some aids, such as mirrors, aluminum reflectors, or magnifying glasses, which would help to focus the heat onto the egg itself. It turns out that eggs also have a bit of an advantage in Arizona, the land of low humidity and high heat. Liquids evaporate rapidly when humidity is low. The eggs have a bit of “help” while they cook, and they dry out faster.
whenlifewassimpler almost 3 years ago
Kate I’d go out and check the hood of my car and the rest of it also.
Chithing Premium Member almost 3 years ago
Give him an egg and let him try. Think of it as a science experiment.
Jeffin Premium Member almost 3 years ago
Noooo! She eggsclaimed.
cuzinron47 almost 3 years ago
How’s he gonna know if he doesn’t try it.
MCProfessor almost 3 years ago
When I was in seventh grade our science teacher left a black iron skillet on the sidewalk in front of our school. The temperature reached 130 degrees F according to the thermometer in the skillet. We were able to fry an egg in it. Air temperature at the time was about 109 degrees F.
briangj2 almost 3 years ago
This question comes from the saying “It’s so hot you could fry an egg on the sidewalk!” How many kids, hearing it, actually try? Most likely they end up with a mess resembling scrambled eggs more than one sunny-side up. So what’s the problem?
An egg needs a temperature of 158°F to become firm. In order to cook, proteins in the egg must denature (modify), then coagulate, and that won’t happen until the temperature rises enough to start and maintain the process.
The sidewalk presents several challenges to this. According to an experiment reported in Robert Wolke’s book, What Einstein Told His Cook: Kitchen Science Explained, sidewalk temperatures can vary depending on the composition of the sidewalk, whether it is in direct sunlight, and of course, the air temperature. Dark objects absorb more light, so blacktop paving would be hotter than concrete. More often than not, sidewalks are concrete. Wolke found that a hot sidewalk might only get up to 145°F. Once you crack the egg onto the sidewalk, the egg cools the sidewalk slightly. Pavement of any kind is a poor conductor of heat, so lacking an additional heat source from below or from the side, the egg will not cook evenly.
Still, the idea of cooking an egg on a sidewalk won’t die. It is so intriguing that the city of Oatman, Arizona, hosts an annual Solar Egg Frying Contest on the 4th of July. Contestants get 15 minutes to make an attempt using solar (sun) power alone. Oatman judges, however, do allow some aids, such as mirrors, aluminum reflectors, or magnifying glasses, which would help to focus the heat onto the egg itself. It turns out that eggs also have a bit of an advantage in Arizona, the land of low humidity and high heat. Liquids evaporate rapidly when humidity is low. The eggs have a bit of “help” while they cook, and they dry out faster.
https://www.loc.gov/everyday-mysteries/item/is-it-possible-to-fry-an-egg-on-the-sidewalk-if-its-hot-enough/
Laurie Stoker Premium Member almost 3 years ago
As I sit here, six inches away from my Arctic Air cooler, I can believe this.