STANDING AN EGG ON END ON THE EQUINOX – AN EXPERIMENT
 

Wayne Osborn
Physics Department, Central Michigan University
January 20, 1999


Background:

A friend of mine several times asked me about the truth in the story that one can stand an egg on end only on the vernal or autumnal equinox. She claims she did indeed balance eggs on end on the equinox as a child. She was reminded of this by each passing of an equinox, but by the time she contacted me it was always well past that equinox and too late to test the claim.

In March of 1998 my friend sent me a newspaper clipping from the Springfield (OH) News-Sun (March 21, 1998) which showed an egg balanced on end.  The caption read

An egg balances over the Pittsfield, Mass., skyline Friday. The balancing act is repeatable only on the vernal and autumnal equinox, when the sun crosses the equator, making night and day equal on all parts of the earth. Friday marked the first day of spring. (AP photo)

I, of course, received the clipping several days after the equinox. But this time I resolved to experiment around the autumnal equinox and put the clipping on the refrigerator as a reminder.
 

The Experiment:

Starting a few days before the autumnal equinox, I attempted to balance an egg on end. Once I mastered the technique, I experimented with standing the same egg on the kitchen counter (abbreviated K in the data table), on a woven place mat on the kitchen table (M), on the bare wood of the kitchen table (T), on the kitchen floor (FL) and on the desk top in the family room (D). The experiment eventually evolved to standing the egg on end on the family room desk, where it could be left undisturbed, and leaving it standing as long as possible. If the egg fell or was knocked over, it was rebalanced in the same location. The experiment was continued until past the winter solstice.  The picture shows the egg standing on the kitchen table.

One particular egg was used throughout the experiment. Occasionally other eggs were used in addition to the main one. All eggs were standard, extra-large, white chicken eggs from the supermarket.

It was fairly easy to stand an egg upright on the woven place mat. It was much more difficult on the smooth surfaces of the counter, wood table, desk and floor. It was soon found that the egg could be balanced on end only in special locations on the smooth surfaces. Looking at light reflecting off these surfaces showed that the special positions had minute bumps or dents. I have concluded that an egg can be balanced at any time of the year but require a minute amount of "support." This support can be provided by small irregularities in the surface or in the shell of egg. The observations are presented in the table that follows.
 

TABLE OF ACTIVITIES AND OBSERVATIONS

Date    Time(EST)  Results/observations

9/16/98     11:00     Attempted to stand egg on end. Gave up after several tries.
9/17        17:40     Attempted to stand egg on end. Gave up after several tries.
9/18                  Stood egg on K, M. Could not balance it on FL, D.
9/19                  Balanced egg twice on T, D.
9/20                  Stood egg on D. Stood briefly on K before falling.
9/21                  Stood egg on T, K.
9/22                  Stood egg on K. A second (cold) egg was balanced on M, K and later on all "good" positions (K, D, T)
9/23         8:40     Stood egg on D
9/25                  Stood egg on D. A second egg was then stood at the same location.
9/27                  Egg still standing on D. Second egg stood on K.
9/28        18:35     Egg still standing on D. Second egg again balanced on K.
9/29        21:00     Egg still standing on D (was checked at 7:30, 11:30, and 21:00).
9/30        14:30     Egg still standing on D.
10/1        17:05     Egg still standing on D.
10/3        16:00     Egg still standing on D.
10/4        18:00     Egg still standing on D. A second egg was balanced on K, T.
10/5         6:00     Egg still standing on D. Dropped a book and it fell; rebalanced on D.
10/6         7:15     Egg still standing on D. Fell while working around it; rebalanced at 7:50.
10/7         6:45     Egg still standing on D from 10/6.
10/8        19:00     Egg still standing on D. Balanced a second egg (cold) on K, 2nd location on D.
10/9         7:00     Egg still standing on D. Found down at 17:15; rebalanced on D.
10/10        8:30     Egg still standing from 10/9.
10/12        8:30     Egg still standing from 10/9.
10/13       12:30     Egg still standing from 10/9. Found down at 17:00; rebalanced on D.
10/14       12:00     Found down. Rebalanced on D and still standing at 18:00.
10/18       14:45     Egg still standing from 10/14. Fell when shutting drawer; rebalanced on D.
10/20       17:00     Egg still standing from 10/18.
10/22       19:00     Egg still standing from 10/18.
10/23       19:15     Found down. Stood on K, then rebalanced at usual location on D.
10/24        8:30     Egg still standing on D from 10/23.
10/26       17:00     Still standing at 17:00 but fell while working. Stood on K, rebalanced on D.
10/29       17:45     Egg still standing on D from 10/26.
11/2         8:00     Egg still standing on D from 10/26.
11/5        13:00     Egg still standing on D from 10/26
11/8        10:00     Egg still standing from 10/26. Found down at 20:15; rebalanced on D.
11/16        8:15     Egg still standing from 11/8. Found down at 20:30; rebalanced on D.
11/18        8:00     Egg still standing from 11/16. Found down at 18:00; rebalanced on D.
11/23        8:30     Egg still standing from 11/18. Fell while working; rebalanced on D.
11/24        8:00     Found down. Rebalanced on D.
12/1        18:00     Egg still standing on D from 11/24.
12/3        20:30     Egg still standing from 11/24. Took down and rebalanced. Egg now cracked.
12/4        19:30     Found down. Rebalanced on D.
12/7        19:30     Egg still standing from 12/4.
12/11        7:30     Egg still standing from 12/4.
12/13       12:00     Egg still standing. Later found down and rebalanced on D.
12/14        8:00     Egg still standing on D from 12/13.
12/16        8:15     Egg still standing on D from 12/13.
12/17       18:30     Egg still standing on D from 12/13.
12/20        8:30     Egg still standing on D from 12/13. Took down and rebalanced.
12/21                 Egg still standing from 12/20. Rebalanced. 2 new eggs stood on D, T, K, M.
1/18/99     20:00     Balanced new egg on K, M, T, FL, D.