
Bright light. PHOTO: Arsgera (1070)
“When you’re in a boat, you see waves of water lap against the hull. If you could tie a flag to a molecule of water, you could see that molecule move up and down. When you’re at a concert, you hear waves of sound press against your ear. If you could tie a flag to a molecule of air, you could see that molecule move back and forth.
“When you tune your radio to your favorite station, you set its sensory organ–the antenna and tuning circuit–to respond to waves of electromagnetic potential energy. If you could tie a flag to … um, what exactly could you tie a flag to?
“The water or air molecule moves. You can measure its spatial displacement as it varies with time, and you can plot those measurements on a graph with displacement along one axis and time along the other. The result is a sinusoidal curve that resembles the form of the water’s surface which we call a wave.
“Hence we speak of water waves, usually without distinguishing the “real” surface feature from the metaphorical mathematical form. And we speak of sound waves, usually without being aware that the term is, in this instance, entirely metaphorical. We have developed mathematical manipulations that enable us, on the basis of metaphorical resemblances, to predict and to utilize various attributes of periodically moving water and air molecules. The wave theory of water and the wave theory of sound have been wondrously productive cognitive tools.
“So, too, we speak of electromagnetic waves. And we have developed mathematical manipulations that have been wondrously productive. We measure voltages or currents; we graph their variation with time; and the graphs have the form of a wave. But what moves? . . .”
Read the entire article posted on March 26, 2018 at thunderbolts.com.
Watch the video based on the article posted on May 7, 2018 at YouTube.com.
link submitted by Robert Petrovich