Does volume of egg change when it is hard-boiled?

Yes, the volume of an egg changes when it is hard-boiled, but the change is very small. Here's why:

* Heat and Pressure: When you boil an egg, the heat causes the water inside the egg to expand and create pressure. This pressure pushes against the egg's shell.

* Shell Porosity: Eggshells are porous, meaning they have tiny holes. Some of the water vapor from the expanding egg escapes through these pores.

* Overall Volume: Although some water is lost, the overall volume change is minimal because the egg white (albumen) solidifies, taking up less space.

Therefore, the volume of a hard-boiled egg is slightly smaller than the volume of a raw egg.

However, the change in volume is not significant enough to be easily noticeable. The visual difference between a raw and a hard-boiled egg is primarily due to the change in texture and color, not the change in volume.