The chemists who uphold dualism are far from being agreed among themselves; nevertheless, all of them in maintaining their opinion, rely upon the phenomena of chemical reactions. For a long time the uncertainty of this...

The color of the emitted light depends on the relative heights of the starting and ending energy levels. A crash between closely spaced levels (such as two and one) releases a pulse of low-energy reddish...

Also unlike a planet, an electron—if excited by heat or light—can leap from its low-energy shell to an empty, high-energy shell. The electron cannot stay in the high-energy state for long, so it soon crashes...

I would like to start by emphasizing the importance of surfaces. It is at a surface where many of our most interesting and useful phenomena occur. We live for example on the surface of a...