Today’s Wonder of the Day was inspired by Christina. Christina Wonders, “ is it possible to cook an egg on the sidewalk ” Thanks for WONDERing with us, Christina!

Which came first? The chicken or the egg? OK…we're not going to answer that question for the ages today. In fact, we're going to ignore the chicken altogether and focus on the egg.

Sometimes, on hot summer days, the rays of the sun beat down with such force that it seems hard to breathe. If you've ever walked home from the local swimming pool on an afternoon during a heat wave, you've probably noticed that the sidewalk soaks up the heat and feels like it might fry your feet.

You might also hear people say, “It's so hot outside that you could fry an egg on the sidewalk!" Is that true? Could you really turn your sidewalk into a frying pan?

Children and adults have put this idea to the test for decades. Some people are so fascinated by the idea that they have annual contests. For example, the city of Oatman, Arizona, has a Solar Egg Frying Contest every 4th of July.

Very few people have successfully cooked an egg on a sidewalk without some extra help. Nevertheless, the next time a heat wave hits your area, grab an egg and get cracking. There's nothing like testing out an idea firsthand.

According to the American Egg Board, eggs need to be heated to a temperature between 144° F and 158° F (62.2° C to 70° C) to be cooked. That's why sidewalks don't make such great frying pans.

Although sidewalks get plenty hot during a heat wave, they don't usually get above 140° F (60° C). They also conduct heat poorly. That means they soak up the heat, but they don't distribute it efficiently to other things, such as eggs.

When you crack an egg on a hot sidewalk, the egg will cool the sidewalk slightly. Without another heat source present, the sidewalk is unlikely to cook the egg much, if at all.

If you really want to fry an egg outside on a hot day, you might have better luck with the hood of a car. Metal conducts heat better and gets much hotter. However, we wouldn't recommend turning someone's car into a frying pan for an egg!

You could also try the sidewalk…but with a little help. Using an aluminum frying pan or some aluminum foil will help conduct the heat from the sidewalk to the egg.

Even still, you'll also likely need to use something else, such as a mirror or a magnifying glass, to intensify the sun's rays to get your egg fully cooked. In case you're WONDERing, the judges of the Solar Egg Frying Contest in Oatman, Arizona, do allow contestants to use items such as these to help cook their eggs.

If you do manage to cook an egg on the sidewalk, don't eat it! You don't want to eat an egg with sidewalk dirt and germs. Feel free to experiment in the name of science, but do all your real cooking in the kitchen!