Naked Eggs

On a shelf in the back of my classroom, I have 18 eggs sitting in a plastic shoebox full of vinegar. They've been there for more than 24 hours at this point, and when I rinsed them and replaced the vinegar this afternoon, most of the eggshells had dissolved, leaving the eggs held together by only a membrane - squishy! Why am I doing this? To demonstrate the role of a membrane and how osmosis works. Tomorrow, we will place our eggs in water, corn syrup, and various salt solutions. On Monday, thanks to the different concentration of solids and water inside and outside the egg's membrane, some of the eggs will have swollen up while others will have shrunk.