How Intuition Messed Up the Laws of Motion

A most fundamental problem, for thousands of years wholly obscured by its complications, is that of motion. All those motions we observe in nature that of a stone thrown into the air, a ship sailing the sea, a cart pushed along the street are in reality very intricate. To understand these phenomena it is wise to begin with the simplest possible cases, and proceed gradually to the more complicated ones. Consider a body at rest, where there is no motion at all. To change the position o...

 Science Manipulates Language to Make it More Precise

Let us consider two spheres moving in different di- rections on a smooth table. So as to have a definite picture, we may assume the two directions perpendicu- lar to each other. Since there are no external forces acting, the motions are perfectly uniform. Suppose, further, that the speeds are equal, that is, both cover the same distance in the same interval of time. But is it correct to say that the two spheres have the same velocity? The answer can be yes or no ! If the speedo- mete...

 Understanding Heat and Temperature

Our sense of touch tells us quite definitely that one body is hot and another cold. But this is a purely quali- tative criterion, not sufficient for a quantitative descrip- tion and sometimes even ambiguous. This is shown by a well-known experiment: we have three vessels con- taining, respectively, cold, warm and hot water. If we dip one hand into the cold water and the other into the hot, we receive a message from the first that it is cold and from the second that it is hot. If we th...

 Heat is a Substance

We recognize in the concept of heat which appears here a similarity to other physical concepts. Heat is, according to our view, a substance, such as mass in mechanics. Its quantity may change or not, like money put aside in a safe or spent. The amount of money in a safe will remain unchanged so long as the safe remains locked, and so will the amounts of mass and heat in an isolated body. The ideal thermos flask is analogous to such a safe. Furthermore, just as the mass of an iso- lat...

 Scientists Read the Book of Nature

IN IMAGINATION there exists the perfect mystery story. Such a story presents all the essential clues, and com- pels us to form our own theory of the case. If we follow the plot carefully, we arrive at the complete solution for ourselves just before the author's disclosure at the end of the book. The solution itself, contrary to those of inferior mysteries, does not disappoint us; more- over, it appears at the very moment we expect it. Can we liken the reader of such a book to the sci...