SMMARTideas

SMMART SCIENCE: EGGSPERIMENTS

Got some extra eggs around after the Easter Holiday?  Try out these fun experiments...

First, observe "the egg".  The architecture of an egg is amazingly strong.

Here you see an electron microscopic view of the hen eggshell; three layers of calcium carbonate.(http://www.csun.edu/~mk411573/discrepant/discrepant_event.html) 

Is a boiled eggshell weaker than a fresh eggshell?  "When shell eggs are hard cooked, the protective coating is washed away, leaving bare the pores in the shell for bacteria to enter and contaminate it."  Does this leave the boiled eggshell structurally weaker? (http://www.fsis.usda.gov/Fact_Sheets/Focus_On_Shell_Eggs/index.asp)

Try squeezing a fresh egg with your fist.  You'll have a hard time cracking it.  Try now with a boiled egg...does the boiled egg crack more easily?

RUBBER EGG

You will need:
Tall glass
White vinegar
Raw egg

Let your child carefully place a whole raw egg (intact with the shell) into a tall glass. Have your child pour white vinegar to cover the egg in the glass. Let the egg sit 2 days (http://www.stevespanglerscience.com/experiment/naked-egg-experiment shows a procedure that involves changing the vinegar and letting it sit for 7 days).

Observe the tiny bubbles that come off of the egg shell. After two days observe how the egg shell dissolves (rinse off the white egg shell residue) and the remaining egg membrane is soft and translucent.

"The bubbles are carbon dioxide gas. Vinegar is an acid called acetic acid - CH3COOH - and white vinegar from the grocery store is usually about 5% solution. Egg shells are made up of calcium carbonate. The vinegar reacts with the calcium carbonate by breaking the chemical into its calcium and carbonate parts (in simplest terms). The calcium part (free ions of calcium float around in the solution) while the carbonate part reacts to form the bubbles that you see. Some of the vinegar will also sneak through the egg's membrane (permeate the membrane) and cause the egg to get a little bigger. That's why the egg is even more delicate if you handle it. If you shake the egg, you can see the yolk sloshing around in the egg white. If the membrane breaks, the egg's insides will spill out into the vinegar. Yes, you've made a pickled egg." (http://www.stevespanglerscience.com/experiment/naked-egg-experiment)

Enjoy these two activities with your child and think about this last eggsperiment if you dye Easter eggs with a dye kit that requires the use of vinegar.  

You have got to check out this fun bunch of research scientists at the U of Nottingham!  Look at all the fun you can have with a Cadbury Creme Egg...

Lisa