Two picket fence sections with slats and rope to make waves.

6H10.30 • E+45+0

diagram for demo

In the first part of this demo, two vertical 'picket fence' wood grids are mounted on the table. A rope extends through both and is attached at the end to a lab stand. When the rope is wiggled up and down, the transverse traveling wave is unobstructed and travels all the way to the lab stand. In the next part, a horizontal wood grid is substituted for the second grid. When the rope is wiggled up and down, the transverse traveling wave passes through the first vertical grid, but is blocked by the horizontal grid. No traveling wave reaches the lab stand. The vertical wood grid could represent a crystal that absorbs all light vibrating in the horizontal plane so that only vertically polarized light is transmitted. (The horizontal grid absorbs light in the vertical plane, etc.) Crystals exist, like Tourmaline, that selectively absorb the E field along one axis, but do not absorb so much along the perpendicular. A modern equivalent is the Polaroid, which is made of iodosulfate of quinine needles lined up parallel in a nitrocellulose mastic.

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6H10.20 Microwaves with grid. Transmitter and receiver are polarized. 6H10.10 Commercial Polaroid filters on an OHP. 6H10.80 Limit of resolution: Two movable pin-points of light.
E+45+61 Shiny object turns black viewed through linear polarizer and quarter wave plate E+45+5 Microwaves with grid. Transmitter and receiver are polarized. E+45+10 Malus experiment: Polarization by reflection off glass surface. E+45+15 Polarization of light by internal reflection: Fresnel rhomb. E+45+20 Polarization of light through a pile of glass plates, using arc lamp. E+45+25 Commercial Polaroid filters on an OHP. E+45+30 Plaster models of positive and biaxial crystals. E+45+35 Two tourmaline crystals act as polaroids, using arc lamp. E+45+40 Light through polaroid and calcite, using arc lamp. E+45+45 Model of a calcite crystal. E+45+50 Light through Nicol prism and Nicol analyzer, using arc lamp. E+45+55 Quartz prisms give a single and double spectrum, using arc lamp. E+45+60 Polarized light and stressed lucite on an OHP. E+45+65 Optical rotation of polarized light by sugar solution, using arc lamp. E+45+70 Optical rotation by sugar solution produces barber pole, using arc lamp. E+45+75 Mechanical model to show circular polarization; hand-cranked. E+45+80 Circular polarization with quarter wave plate, using arc lamp. E+45+85 Circular polarization of microwaves by elliptical metal tube. E+45+90 Circular polarization of microwaves: With reflector and grids. E+45+95 Polarized light thru Karo syrup shows dark bands, using arc lamp. E+45+100 10_ retarder plate makes dark bands in spectrum, using arc lamp. E+45+105 Sunset: solution in tank scatters blue light, using arc lamp. E+45+110 Visible nodes and antinodes in linearly birefringent plexiglass rod. E+45+115 Applet: Polarization of Light (3-D Version)