In the video above, sound waves passing around and through a drop of mercury set it oscillating. But the physics of the system — determined by things like the speed of sound in mercury and the strength of its surface tension — allow some sound waves to excite special vibrations in the drop. In other words, the mercury drop has resonances with the sound at specific frequencies.
These are called the resonant modes of the drop. When the frequency of the sound waves matches the frequency of the drop’s resonant modes, highly organized patterns of pulsation are triggered. You know you’ve hit strong resonances when something like a multiple-armed, star-shaped pattern emerges.
It’s a remarkable reminder of the hidden architectures embedded in the world around us.
When a magnetic field moves through a conductor a current called an Eddy current is induced in the conductor due to the magnetic field’s movement. The flow of electrons in the conductor creates an opposing magnetic field to the magnet which results in damping of the magnet and causes heating inside of the conductor similar to heat buildup inside of power cords. The loss of energy used to heat up the conductor is equal to the loss of kinetic energy by the magnet.
And a note of caution if you decide to try this, these magnets are not for unsupervised children. In fact, everyone should be careful:
Neodymium magnets larger than a half inch are very strong and should be handled with extreme care since they can be dangerous. It is best to stick with neodymium magnets of quarter inch diameter or less.
What’s happening when a match is lit? From Answers.com:
Matches contain sulfur, glass powder, and an oxidizing agent as the components in the match head. When you strike a match, the friction due to the particles of glass powder rubbing together generates enough heat to convert some of the red phosphorous to white phosphorous, which burns in the presence of oxygen gas. The heat from the friction also causes the oxidizing agent to produce oxygen gas, igniting the small amount of white phosphorous. Once ignited, the oxygen gas fuels the flame while the rest of the sulfur catches on fire. Of course, this entire process happens in a fraction of a second.
"It was the craftsmen who mastered the remarkable properties that go with specific materials. They were the first to journey towards the atom. The goldsmiths slowly refined their craft to take advantage of what gold alone could do…”