Does the gravitational pull of the sun vary from one day to the next? There are some who say that it does, and that it can be especially strong on the equinoxes—strong enough even to balance a raw egg upright! This theory is unproven, but can prove a fun activity for kids, as well as a great opportunity to talk to them about the sun, the force of gravity, and the concept of balance. Using grains of salt to balance the egg, meanwhile, can further illustrate points about balance.
This two-part experiment is best attempted on one of the equinoxes—March 20 or September 23—but it can really be done any time! All you need for the first part of the experiment are a raw egg and a hard surface! Encourage your kids to try to balance the egg, upright, pointing upward. They will likely find this to be difficult, if not outright impossible! Then, create a small mound of salt on that same hard surface. Encourage them to try balancing the egg atop this mound of salt. It should prove much easier now! Once the egg is balanced, very gently blow the excess salt away.
One raw egg and a little bit of table salt, along with a flat, hard surface, are all you’ll need.
Your child will consider the force of gravity, and in particular gravity’s relationship to the sun. He or she may also be led to think about balance. The experiment may also cultivate your child’s spatial reasoning abilities.