Trying to get an egg to stand up

On the 20th of march it was the Vernal Equinox and Granddad told the girls that this was the only day of the year and between 1:15 and 1:45 in the afternoon was the only time that you could make an egg stand up. And he challenged the girls to try it and Big sis #1 being the smarty pants that she is tried it and right off she got it to stand up. Mind you it was at 10:00 that morning. So we marked that egg so that in a couple of days we tried it and it will still stand up but the other eggs we tried wont stand up it was a fun little thing to do the girls thought that it was neat.