# Partial pencil pressure

### Celebrating the 70s - 50th Celebration of Chem 13 News

It has recently been observed that some of the commonplace events and circumstances around the ordinary home are illustrations of the laws of science, and may be, in part, explained by them.

For example, let us consider the observation that you can never find a pencil when you want one. You try to keep one by the telephone, one by the family bulletin board, one in the tray on your desk and one in the possession of each of your children. Observe that a pencil in each of these specified locations represents order, i.e., a low entropy. The second law of thermodynamics demands that in a closed system, when any process takes place, the entropy must rise. It follows therefore that pencils cannot remain in these locations.

Of course, a normal home is not a closed system. This does not help. It works this way. You decide that if you supply enough pencils, fast enough, eventually you should be able to saturate the system, so that there should be a pencil everywhere you look. But there is enough leakage that all you ever achieve is a steady state (to be distinguished from equilibrium) in which the rate of pencil leakage equals the rate at which pencils are supplied. In this case, the partial pencil pressure within the system never reaches saturation.

Occasionally, by heroic efforts to approach a closed system by reducing the rate of leakage (forbidding the children to take pencils outside), or by increasing the rate of supply, one may almost reach the saturation level. Then if the temperature of the system is lowered, as by a cooling off in the activity of school projects, the partial pencil pressure may be found to be greater than saturation, and pencil precipitation may occur. This explains the little heap of pencils you found on top of the piano last week, and vindicates the law of conservation of mass.

Work is proceeding on related phenomena, concerning coat hangers, paper clips and telephone calls.