How would you describe Beer’s Law after viewing this video?
Simple discussion of the Beer-Lambert-Bouguer Law (a.k.a. Beer's Law) using root beer.
How do LEDs produce warm and cool white light?
Multiple demonstrations illustrating how light emitting diodes (LEDs) can produce warm and cool white light. Thanks to Kathryn Campbell for shooting the video.
Why is snow white?
Snow appears white because the difference in refractive index between the ice and the air between the ice helps to bend and scatter white light. Placing snow in water turns the snow nearly invisible because the refractive indices of solid and liquid water are more similar, and light is bent less.
Does a pickle conduct electricity? How?
High voltage alternating current is sent into a pickle. The salt water inside the pickle conducts pickle conducts electricity and the pickle glows yellow near one electrode as sodium ions inside the pickle are excited. WARNING, DO NOT TRY THIS! The high voltages associated with this demonstration make it dangerous and the pickle also burns somewhat, producing noxious smoke.
What type of light scattering do you think is occurring?
Light Scattering in and Near a Glacier-Fed Creek
The light scattering exhibited is more likely Mie scattering from particles bigger than the wavelengths of visible light than Tyndall scattering from particles about the same size as wavelengths of visible light, as the scattered light is not noticeably bluish in color.
What causes the beautiful colors of a sunset?
Time Lapse of Sunset on Mt. Adams at Takhlakh Lake, WA, on 07-07-07
A very pretty sunset at one of the prettiest places I have ever been. I like how the colors on the mountain shift from white to yellow to orange to red to purple. As the sun sets, its rays travel longer distances though the the Earth's atmosphere. More of the shorter wavelengths in the sunlight are scattered from components in the atmosphere, and as a result, the sun and the light it casts appears more red.
What is the difference between additive color mixing and subtractive color mixing?
Demonstrating Color Mixing with the Color Cube Model
The Color Cube model can be used to illustrate color mixing. In additive color mixing, red, green, and blue combine to produce white. In subtractive color mixing, cyan, yellow, and magenta combine to produce black
What causes the fluorescence in this demo?
Tonic water fluorescence quenched with iodide ions
Degassed tonic water fluoresces blue when excited by a 405 nm violet laser. The fluorescence is largely quenched by the addition of iodide ions.
A 365 nm LED light source is shined on various glass items, causing some to fluoresce. It appears that cadmium sulfide in glass glows an intense orange, selenium in glass glows orange, and manganese in glass glows yellow or red. Thanks to Tom Kahila for the loan of the light source.
A 365 nm LED light source is shined on uranium-containing depression glass, causing it to fluoresce green. Thanks to Tom Kahila for the loan of the light source.
Flickering flame LED light also flashes (CAUTION: Flashing light!)
My neighbor's flame LED light seems to convert between a flame pattern (first part of the video) to more simply a flashing light (second part of the video). Do cold temperatures make it flash? I'm not sure.