Week 2 (March 16)

Chapter 3: The Golden Dane – Points to ponder

• An atom is mostly empty space, its nucleus being 100,000 times smaller in diameter than the atom. Does it make sense to you that you’re sitting and standing on materials composed of atoms like that?

• Does it help you to try to understand an atom by visualizing it as a sun-and-planets system?

• Strontium-90 is a radioactive product of nuclear fission which settles in bones because it is chemically like calcium. It has a half-life of about 30 years. What fraction of it is left after 90 years? Why might that worry you? [Its decay product, Yttrium-90, is also radioactive, with a 64-hour half-life]

Chapter 4: The Quantum Atom – Points to ponder

• Can you visualize Bohr’s “stationary state” for an electron in an atom? Note that classically, a non-moving electron is drawn directly to the nucleus, and that an electron in a circular orbit loses energy and spirals into the nucleus, making such an atom unstable.

• How important is it to have an image of the Bohr atom? Would some mathematical equations be sufficient?

• What do we have available with which to construct an image (think of the story of the blind men describing an elephant)?

Chapter 5: When Einstein met Bohr – Points to ponder

• Why is causality such a big deal? What’s the problem with a little randomness?

• Conservation of energy (i.e., energy cannot be created or destroyed) is considered to be a fundamental law of physics. Can you think of any evidence for this law? What might take place if energy could be created?

Updated Jan. 21, 2023