Should eggs float or sink?

I'm curious, when it comes to the question of whether eggs should float or sink, what's the scientific reasoning behind it? Is it a matter of the egg's freshness, or perhaps the temperature of the water? And how does this relate to the culinary world? Could knowing the answer help in determining the quality of eggs used in baking or cooking? I'm eager to learn more about this intriguing question and the factors that influence an egg's buoyancy.