He reminded us that ferromagnetism gives rise to the strong attractive and repulsive forces that most of us associate with magnetism and permanent magnets. But then he told us about diamagnetism , which gives rise to forces about 100,000 times weaker than ferromagnetism . He then moved the magnet close to the Bi pellets and then away, repeatedly using any very weak repulsive force to push the pendulum into motion.
Some students feel religion and science are incompatible.
Don cited the view of creationists that the earth was created something like 5000 or so years ago, or in 6 days by the Bible, while science believes that the universe started with the Big Bang more than 10 billion years ago. Don wrote down Einstein's equations from special relativity for relative velocity and time dilation, and used these to argue that if God operates near the speed of light, then the viewpoints of religion and science may agree. Once the mercury is ionized, the ions give off light when atoms go back to states of less energy. The light energy, mostly not in a useful visible range, then reaches the phosphors coating the inside wall of the fluorescent bulb, and the phosphors then absorb that energy and emit light in a useful range for us to see by. This got us into a discussion of possible dangers of fluorescent bulbs - the hazards of mercury .