Is the date on the carton past its expiration date? Don’t throw it away just yet! Look closely at this image: if the egg floats at the top of the glass, is it still edible or is it dangerous to your health?

Why does it float? The science behind the egg

An eggshell   is  porous, allowing air to pass through. As the egg ages, more of the water inside evaporates through the micropores in the shell.

In place of this water, an  air pocket  (called the air cell) forms and grows day by day. It is this air bubble that acts like a mini buoy and keeps the egg afloat when it is too old!