Six Easy Pieces: Essentials of Physics Explained by Its Most Brilliant Teacher

We would like to emphasize a very important difference between classical and quantum mechanics. We have been talking about the probability that an electron will arrive in a given circumstance. We have implied that in our experimental arrangement (or even in the best possible one) it would be impossible to predict exactly what would happen. We can o

We conclude the following: The electrons arrive in lumps, like particles, and the probability of arrival of these lumps is distributed like the distribution of intensity of a wave. It is in this sense that an electron behaves “sometimes like a particle and sometimes like a wave.”

In order to verify the conservation of energy, we must be careful that we have not put any in or taken any out. Second, the energy has a large number of different forms, and there is a formula for each one. These are gravitational energy, kinetic energy, heat energy, elastic energy, electrical energy, chemical energy, radiant energy, nuclear energy

We call the sum of the weights times the heights gravitational potential energy—the energy which an object has because of its relationship in space, relative to the earth.

other conservation laws there are in physics. There are two other conservation laws which are analogous to the conservation of energy. One is called the conservation of linear momentum. The other is called the conservation of angular momentum.

“It is impossible to design an apparatus to determine which hole the electron passes through, that will not at the same time disturb the electrons enough to destroy the interference pattern.” If an apparatus is capable of determining which hole the electron goes through, it cannot be so delicate that it does not disturb the pattern in an essential

The general name of energy which has to do with location relative to something else is called potential energy. In this particular case, of course, we call it gravitational potential energy.

Any great discovery of a new law is useful only if we can take more out than we put in.

Why can we use mathematics to describe nature without a mechanism behind it? No one knows. We have to keep going because we find out more that way.