Kids, do eggshells have tiny holes?  This easy science experiment focuses on some of the interesting characteristics of eggs.   Prove the existence of a small air pocket inside an egg as well as thousands of small holes in the shell, called pores, all while learning what air does as it is heated.

What you'll need:

• A clear glass or jar, such as Pyrex™, that won't break with the sudden addition of hot water
• An adult partner to handle hot water 
• A pan of hot water. It shouldn't be so hot as to be a hazard to work with
• A raw egg
• A magnifying glass
 
Instructions:

• Place the egg carefully into the glass or jar.
• Carefully pour hot water into the glass or jar until it is nearly full.
• Leave the glass or jar on a table and watch the egg closely for a few minutes; the glass may become hot so be careful.
• Use your magnifying glass to closely examine what is happening.
 
What's happening?

After surrounding the egg with hot water you will notice tiny bubbles forming on the eggshell which eventually bubble their way to the surface of the water. An egg contains a small air pocket at its wider end between the shell (calcium carbonate) and the egg white (albumin). When the air trapped inside this small pocket begins to heat up, it expands and tries to find a way out of the shell. How does it escape?

They're too small to see under normal conditions, but with the help of a magnifying glass you can see that egg shells contain thousands of small holes, called pores. The pores allow air to pass through the shell, making it look like the egg is bubbling as the air expands and is forced through the shell.

Bumpy and grainy in texture, an eggshell is covered with as many as 17,000 tiny pores. An eggshell is made almost entirely of calcium carbonate (CaCO₃) crystals. It is a "semipermeable membrane", which means that air and water can pass through its pores. The shell also has a thin outermost coating called the bloom or cuticle that helps keep out bacteria and dust.  Do a Google Images search for "egg shell pores" and you'll be amazed at the images you see.

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References:
http://www.sciencekids.co.nz/experiments/eggbubbles.html
https://www.exploratorium.edu/cooking/eggs/eggcomposition.html