Question

Dear Mitch,

The other day you said there's an easy (and almost completely "mathless") way to determine the surface area of an egg, and I don't think you've posted it yet. Would you please do it soon?

Sincerely,

Todd

Bethlehem, PA

Answer

Dear Todd,

Yes, I did say there's an easy (and almost completely 'Mathless' way) to determine the surface area of an egg. And here, in a format based upon what teachers refer to as a "lesson plan", is the method:

Materials:

- one balance scale
- Several empty eggshells of whatever size and type of egg you used to make your dyed Easter eggs. (Empty shells can be obtained in a number of ways. ) Since the shells do not have to be kept intact (They do not have to be unbroken the way they would for emptied eggs that you would decorate for Easter baskets), the most straightforward way to do it is to just crack open raw eggs one at a time and empty their contents into a bowl. Note: Questions will arise regarding the wastage of the eggs. In fact, there is no need to waste any eggs. Rather, the bowl containing them could be used to make cookie batter which is turned into cookies for the class to consume upon successful completion of the lesson, or, perhaps, the teacher can serve the class a scrambled egg breakfast with bagels, etc. before beginning the Easter Vacation. Regardless of what you decide to do with the egg contents, be prepared for the question.

Procedure:

Depending upon the accuracy/calibration of your scale, you will either need to flatten out sections of eggshell (working as precisely as you can with a sharp knife) and carefully group pieces into 1-inch x 1-inch squares, or, more of these units, i.e., ten separate one-inch squares, to get a visible measurement on your scale. (In such a case, the weight will simply have to be divided by ten after reading the scale. Do it prior to class-time so that you have an idea what the result should be, even if you decide to have students do it on their own as well.)

Then using the known weight (that you have just derived) of a square-inch of eggshell, the class, working in groups, can break up an entire egg (one egg per group is one way that seems to work well) and then they should be asked to rearrange the pieces into square inches to make pre-measurement estimations.

Finally, an entire eggshell is put on one side of a balance scale; on the other side of the scale is stacked as many flattened square inches of eggshell as is necessary to obtain the balance. One or two of the square inches may have to be cut into halves, quarters, even thirds or eighths.

Moving from weight to surface-area, the surface area of a single egg can then be determined in square inches!

Hope this helps,

Mitch