Francesco Redi, he put meat in jars and waited.
Ovalbumin is the component of egg white which is responsible for foam formation.
Ovalbumin is the main protein component of the egg white and it is responsible for creating the foam structure when the egg whites are beaten. The physical stress caused by beating the egg white, causes the protein ovalbumin to denature and unfold. This denaturation, along with the mixing of air in the egg white, causes the formation of foam.
arbon, as with many elements, can arrange its atoms into several different geometries, or "allotropes." In pure diamond, every carbon atom is covalently bonded to exactly 4 other carbon atoms in a very specific and energetically favorable geometry. The diamond cannot be broken or scratched unless many covalent bonds are broken, which is difficult to do. In another common allotrope, graphite, every carbon atom is covalently bonded to only 3 other carbon atoms, and the atoms are arranged in sheets that are not covalently bonded to each other. The sheets can be broken apart easily, ultimately meaning that graphite can be easily scratched. Coal is composed of particles of different allotropes of carbon, and some "amorphous carbon," which has no defined geometry in its atomic structure. Without a continuous network of covalent bonds, coal is easily scratched (i.e. it is not hard).
