Yes, just place the egg in at least several inches of water in a bowl or pot. If your egg sinks and lies on its side, you have a fresh egg. If it sinks but stands partially or fully erect on its tapered end, your egg is already over the hill, though technically still edible. If it floats, you are looking at a rotten egg, more suitable for a garbage bin than a stomach. An egg acquires buoyancy as it ages because, while its yolk and albumen (egg white) are gradually losing moisture to the outside world through the porous shell, the size of its air pocket is increasing.