I would think the double slit interference pattern is a standing wave as well, because the nodal lines are stationary. In that case, reflection is not a requirement.
Many sunglasses have polycarbonate lenses. Polycarbonate inherently blocks UVA and UVB (cutoff at 400 nm). The unrelated phenomenon of photochromism occurs in a specific lens coating. It can be induced by visible violet and by ultraviolet.
(Fun experiment: a photochromic polycarbonate lens does...
"Photochemical change" and "darkening under UVA light" is typical for photochromic sunglasses. Are you perhaps using the word "quality" as a synonym for "photochromic"?
Nice observation! On the other hand, an argument against that explanation is that an ordinary camera is able to capture the same ring phenomenon, in the absence of human anatomy, retroreflectors, holograms, illuminated inner eyes, and fair complexions, as shown by photos in previous posts.
Another way to look at that question is these two graphs. The first one shows the radius of the secondary rainbow is zero (which corresponds to the center of the rainbow) for an index of refraction of about 1.17; the radius of the primary rainbow does not tend to zero for any n. The second graph...
The metric prefix "tera" comes from the Greek word teras or teratos, meaning "marvel, monster", whereas "tyra" in tyrannosaur is derived from tyrant. Tera and tyra seem to have a somewhat similar original meaning, are they perhaps essentially the same?
I used a cheap high voltage generator from ebay. When connected to the Geissler tube, it produces 5 kV pulses, and each pulse results in a discharge through the gas, at 60 mA during 2 μs. Maybe a traditional Ruhmkorff coil generator would produce a higher current and another pulse duration.
You...
A website selling geissler tubes compares their "new style geissler tube" to the "old style tubes". It says the old style tubes are inferior because "spurious emissions in the spectrum are of considerable number and intensity". Unfortunately, the website does not specify the cause of the...
Using a hand spectroscope, I looked at the spectrum of two geissler tubes, helium and hydrogen. The helium spectrum is what I expected, dominated by five distinct lines. The hydrogen spectrum, however, is somewhat disappointing. It is dominated by an almost continuous spectrum, it is not evident...
Seeing the rings around the eyes in a bathroom mirror is slightly difficult because the mirror usually is not uniformly misted. It helps to move your head sideways while watching the mirror, because the motion averages the mist, in a way. Such a sideways motion also helps when trying to take a...
You may be right, but I am not sure what the equivalent particles are, and how they could be photographed. For the time being I prefer thinking the equivalent particles are actually etched micro pits into the smooth glass surface, created for a matte appearance. I took the picture below with my...
The wikipedia article on Lunar distance contains a confusing graph. The graph seems to suggest that the eccentricity of the lunar orbit is maximal in january and ~july, and minimal in april and ~october. I think the eccentricity should be constant. Is wikipedia right or wrong, or is there some...
Electrons flowing through a resistor are dissipating electrical energy. The electrical energy is transported from the battery to the electrons along the curved field lines of the Poynting vector. It seems like a meaningful idea that electrical energy necessarily travels from the source to the...