Every time the first day of fall or spring rolls around, you might hear of the neat trick you can do on the equinox: You can stand an egg up on its end!
It turns out it's true! You can stand an egg on its end on the equinox.
And on your birthday.
And on Flag Day.
And your anniversary.
Or any of the other 361 days (or sometimes 362 -- it works on Feb. 29 too!)
Suffice to say, you can stand an egg up on any day of the year, provided the egg is in the proper condition.
The myth that it's an equinox-only event seems to step from an idea that gravity is somehow balanced when the sun and Earth's tilt are precisely aligned.
"(Sounds) like science, but it isn't," said National Weather Service forecasters in Birmingham, Alabama. "There are many forces acting on an egg when you try to stand it on end on a flat surface. Some people think that the gravitational pull of the sun becomes balanced with that of the Earth to allow for this phenomenon to occur."
But the National Weather Service says the moon exerts a much stronger gravitational effect on the Earth than the sun, dominating the ebb and flow of the ocean tides.
"The moon's effects are different at each of the equinoxes, however," they said. "The most dominant force of gravity on a standing egg is the one between the Earth and the egg itself. This is determined by the weight of the egg and the force pulling the egg to the countertop."
And this is one scientific experiment you can prove to yourself at home.
"Take a fresh, uncooked egg and hold it with the larger end resting on a table or countertop. Wait for the fluid content of the egg to settle, then carefully test the balance," the NWS said. "Be patient as you find the point where you can ever so gently let it go to remain standing on end."
Feel free to give it a go on the first day of autumn. And again on Halloween. Or Thanksgiving. Or January 19th.