The Age Old Question. Can you fry an egg on the sidewalk?

Demonstrating an egg cooking in the water of Hot Creek Gorge thermal area, California.
USGS Web site.

Women frying eggs on cement wall near U.S. Capitol.
Prints & Photographs Division, Library of Congress.

Wit the summer heat rising, there are some of us who like to say "it's so hot you can fry an egg on the sidewalk". It's unclear who really started that metaphor however, if you stop and think about it, can you really fry an egg on the sidewalk?

In theory maybe you could but, does the sidewalk actually get hot enough?



In a scientific nutshell, 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.

So if you cannot fry your egg on the sidewalk, where can you fry it (besides the stove)?
Something closer to the conditions of a frying pan would be the hood of a car. Metal conducts heat better and gets hotter, so people actually have been able to cook an egg on a car hood's surface. Would you need an item such as Pam to prevent sticking?


Getting back to the sidewalk idea, 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.

library of congress