Boiling an egg transforms its liquid contents into a solid due to the denaturation of proteins, specifically albumin, found in the egg white. When heated, these proteins undergo chemical changes, leading to a solid structure rather than turning into gas, which is common in other heating processes. The boiling water does not reach the boiling point of the egg's contents due to the mixture of compounds present. This process exemplifies how heat induces chemical reactions in cooking, altering flavor, texture, and appearance, such as the browning of bread through caramelization. Albumin is a water-soluble protein that coagulates when heated, and it is distinct from enzymes or hormones, with other forms present in human blood as well.