#acl Narf:read,write,delete,revert,admin FacultyGroup:read,write All:read == Photometry == ''PIRA classification 6B'' ||<#dddddd>Grayed Demos are either not available or haven't been built yet. || = 6B10. Luminosity = ||<10% style="text-align:center">'''PIRA #''' ||'''Demonstration Name''' ||'''Subsets'''||<60% style="text-align:center">'''Abstract''' || ||6B10.10 ||checker board || ||Use a point source to superimpose shadows of a rectangle and a 3h x 3w checkerboard rectangle. || ||6B10.10 ||inverse square law || ||A rectangular paddle and a 3Hx3W paddle are placed so shadows overlap and the distances are measured. || ||6B10.15 ||inverse square model ||pira200||A wire frame pyramid connects areas of 1, 4, and 9 units. || ||6B10.15 ||inverse square model || ||A wire frame pyramid connects areas of 1, 4, and 16 units. || ||6B10.20 ||inverse square with photocell || ||Double and triple the distance from an arc source to a photocell connected to a galvanometer. || ||6B10.20 ||foot-candle meter || ||Use a Weston type foot-candle meter to measure the inverse square law. || ||6B10.20 ||inverse square law || ||Double and triple the distance between a source and photometer. Graph. || ||6B10.30 ||paraffin block photometer || ||Two large paraffin blocks with tin foil sandwiched in between make a sensitive photometer. Use with lamps on either side. || ||6B10.30 ||paraffin blick photometer || ||Two paraffin blocks separated by an aluminum sheet are moved between two light sources until they appear equally bright. || ||6B10.30 ||Joly diffusion photometer || ||Tin foil is sandwiched between two blocks of paraffin. Can be mounted in a box for greater accuracy. || ||6B10.35 ||grease spot photometer || ||A piece of paper with a grease spot is moved between two light sources until the spot disappears. || ||6B10.35 ||Bunsen grease-spot photometer || ||A grease spot disappears when illuminated equally from both sides. Diagram of a grease-spot box. || ||6B10.40 ||Rumford photometer || ||Light sources are moved until their shadows of the same object are of equal intensity. || ||6B10.40 ||Rumford shadow photometer || ||Two light sources are moved so the shadow cast by a vertical rod is of the same intensity. || ||6B10.50 ||frosted globe - surface brightness || ||The surface brightness of a 40 W bulb is compared to a frosted globe placed over it. || ||6B10.50 ||surface brightness || ||A lamp with measured candlepower is enclosed in a frosted globe. || ||6B10.60 ||surface brightness of a lens || ||Place the eye at the image point of a lens focused on a dim lamp. || ||6B10.65 ||reflected surface brightness || ||With a bright spot at the object point of a concave mirror and the eye at the image point, the whole mirror seems to have the same surface brightness as the spot. || ||6B10.70 ||laser and light bulb || ||A .5 mW laser beam can be seen on the glass beside the bright center of a 25 W frosted incandescent bulb. || ||6B10.80 ||covered strobe and detector || ||The amplitude of a signal displayed on an oscilloscope from a translucent covered photodetector and from a translucent covered strobe changes as the angles and distances are changed. || = 6B30. Radiation Pressure = ||<10% style="text-align:center">'''PIRA #''' ||'''Demonstration Name''' ||'''Subsets'''||<60% style="text-align:center">'''Abstract''' || ||6B30.10 ||radiometer - quartz fiber || || || ||6B30.10 ||radiation pressure || ||Construction details for a quartz fiber radiometer. Deflection of one radian is easily achieved with a microscope lamp. || ||6B30.10 ||radiometer || ||The deflection of a quartz fiber radiometer is measured statically under high vacuum. || ||6B30.11 ||radiometer || ||Focus a beam of light intermittently on a vane of the quartz fiber radiometer at the frequency of oscillation. || ||6B30.20 ||light pressure comment || ||Brings attention to a paper that devotes six pages to describing errors in the "classical work by Nichols and Hull". || = 6B40. Black Bodies = ||<10% style="text-align:center">'''PIRA #''' ||'''Demonstration Name''' ||'''Subsets'''||<60% style="text-align:center">'''Abstract''' || ||6B40.10 ||variac and light bulb || ||Vary the voltage to a 1 KW light bulb with a variac to show color change with temperature. || ||6B40.10 ||variac and light bulb || ||Vary the voltage across a clear glass lamp from zero to 50% overvoltage. Also measure the intensity and plot against power. || ||6B40.20 ||hole in a box || ||Holes in black boxes are blacker than the boxes. One box is painted white inside. || ||6B40.20 ||hole in a black box || ||A box painted black has a hole in the side. || ||6B40.20 ||Bichsel boxes || ||Two black boxes have blacker appearing holes in them. One box actually is painted white inside. || ||6B40.25 ||carbon block || ||A carbon block with a hole bored in it is heated red hot with a torch. The hole glows brighter. || ||6B40.25 ||hole in a hot ball || ||A iron ball with a hole is heated red hot. || ||6B40.26 ||carbon rod || ||Bore a hole in an old carbon arc rod and heat electrically. The hole glows brighter. || ||6B40.30 ||radiation from a black body || ||Heat red hot a carbon block the has both a drilled hole and a white porcelain plug. || ||6B40.30 ||carbon block and porcelain || ||Two holes are drilled in a carbon block, one is filled with a porcelain insulator, and the block is heated with a torch. || ||6B40.30 ||graphite and porcelain || ||Graphite and porcelain heated red hot look the same. A pattern on a porcelain dish shows brighter when heated. || ||6B40.35 ||good absorbers - good radiators || ||An electric element (E-171) with chalk marks or china with a pattern are heated until they glow. || ||6B40.40 ||X-Y spectrum recorder || ||The black body radiation curve is traced on a X-Y recorder from a thermopile. detector riding on the pen arm. || ||6B40.41 ||IR spectrum on galvanometer || || || ||6B40.41 ||plotting the spectrum || ||Measure the output of a thermopile. as it is moved across a spectrum. Monochrometer in appendix, p. 1362, Plots. || ||6B40.41 ||radiation intensity curve || ||Explore the energy distribution of the continuous spectrum of a carbon arc with a sensitive thermopile. and galvanometer. || ||6B40.41 ||infrared in spectrum || ||Hold a thermopile. connected to a galvanometer in different parts of a spectrum. || ||6B40.42 ||mapping the spectrum || ||Use a thermopile. and galvanometer to show the infrared energy in the continuous spectrum. Insert a water cell. || ||6B40.45 ||IR camera and projected spectrum || || || ||6B40.50 ||IR camera and soldering iron || || || ||6B40.55 ||project sprectrum and change temperature || || || ||6B40.55 ||radiation vs. temperature || ||A more detailed look at varying the temperature of a black body and measuring with a thermopile. || ||6B40.55 ||radiation spectrum of a hot object || ||Project the spectrum from a projector lamp and change the voltage. || ||6B40.62 ||Stefan-Boltzman equation || ||Measuring sigma by the relative method using a Hefner lamp as a standard radiator. || ||6B40.70 ||microwave blackbody || ||Microwave radiation emitted or absorbed by a cavity is detected and displayed on an oscilloscope. || [[Demonstrations]] [[Instructional|Home]]