Recent content by Orthoceras

The blue/red color change occurs in some globes halfway the streamer, so not always at the border between streamer and pad. A paper, by the Princeton Plasma Physics Laboratory, on Measurements of the motion of filaments in a plasma ball says the color change is presumably caused by the lower...

The orange of neon, and the blue of argon/xenon, are fluorescence colors. De-excitation occurs in a sequence of smaller energy steps, whereas excitation occurs in a single step.. According to the Wikipedia quote in the post by renormalize, the pressure in the globe is similar to one atmosphere...

I'm sorry I annoyed you with my question. However, your quote from Wikipedia does not really answer my question about the different colors. What I meant with the question is more in line with the Franck-Hertz experiment. The first excitation energy for neon is 16.6 eV, for argon it is 11.6 eV...

I have a common plasma globe with blue streamers and orange pads at both ends. The orange light is emitted by neon and the blue light is presumably emitted by argon and xenon. Why are the streamers blue while the pads at both ends are orange? A plasma globe's electric field is strong near the...

About the reflective strips: "IPS" (In Plane Switching) liquid crystal displays have "interdigital electrodes" within each pixel. That is, multiple electrode strips, and neighbouring strips are connected to opposite poles. As a result the electric field is approximately parallel to the surface...

Some tv-screens, such as LG, have multiple reflective strips (electrodes?) within a pixel. The groove period of these strips is 0.03 mm, so the angle between red maxima is 1° (λ = 600 nm). In some situations that produces a rainbow effect. However you need a bright point source, such as a lamp...

A formula for the frequencies of partially filled wineglasses was derived by A.P. French in 'In vino veritas, a study of wineglass acoustics' (1983). This derivation is sometimes referred to in high school lab reports. You may find it here.

Sorry, I did not really understand your test descriptions. What do you mean by "coil" (in "attaching a coil to the electroscope", "inside the jars are some copper coils" and "coil-activated containers"), by "waving" (in "waving the polystyrene on the coil") and by "it works"? Anyways, your...

Test the insulation. Disconnect the wires. Charge a balloon by rubbing it against hair or wool. Connect the electroscope to inductor 1, and try to charge the inductor with the charged balloon. If the electroscope leafs do not rise, the inductor is not properly insulated. Do the same insulation...

That unit name is unknown in the English wikipedia. I am not sure I would trust the statement in the German wikipedia. It does not seem likely that the British Association in 1888 was unaware of a unit name conflict. In contrast, they said the uncouthness of some of these terms was put forward...

In 1888, a committee of the British Association proposed "bole" as the name for the unit of momentum. (link)

It is a shadow image. In my experience the easiest way to view floaters is looking through a pinhole at a bright surface. The smaller the pinhole the better, but not too small. I got the sharpest view of my floaters with a 0.2 mm pinhole, made by poking a very tiny hole in a piece of aluminium...

Sorry, my mistake was already discussed and solved some time ago, here.

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...