Why do eggs not turn to liquid when heated (boiled)?
Actually change of state implies turning of a PURE SUBSTANCE from liquid to solid when temperature is low (this composition remains constant and no alteration in composition or structure takes place). But egg contains a mixture of many substances, such as protein, carbohydrate etc. When proteins are heated, their structure changes (this is called “de-natured”), and they become more rigid. This is what happens when you cook an egg. The following is from Wikipedia (and the link to the page is found on the left of this answer: When proteins are heated they become de-natured and change texture. In many cases, this causes the structure of the material to become softer or more friable – meat becomes cooked. In some cases, proteins can form more rigid structures, such as the coagulation of albumen in egg whites. The formation of a relatively rigid but flexible matrix from egg white provides an important component of much cake cookery, and also underpins many desserts based on meringue. Other
