Photometry
PIRA classification 6B
Grayed Demos are either not available or haven't been built yet. |
6B10. Luminosity
PIRA # |
Demonstration Name |
Subsets |
Abstract |
6B10.10 |
checker board |
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Use a point source to superimpose shadows of a rectangle and a 3h x 3w checkerboard rectangle. |
6B10.10 |
inverse square law |
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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 |
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A wire frame pyramid connects areas of 1, 4, and 16 units. |
6B10.20 |
inverse square with photocell |
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Double and triple the distance from an arc source to a photocell connected to a galvanometer. |
6B10.20 |
foot-candle meter |
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Use a Weston type foot-candle meter to measure the inverse square law. |
6B10.20 |
inverse square law |
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Double and triple the distance between a source and photometer. Graph. |
6B10.30 |
paraffin block photometer |
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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 |
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Two paraffin blocks separated by an aluminum sheet are moved between two light sources until they appear equally bright. |
6B10.30 |
Joly diffusion photometer |
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Tin foil is sandwiched between two blocks of paraffin. Can be mounted in a box for greater accuracy. |
6B10.35 |
grease spot photometer |
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A piece of paper with a grease spot is moved between two light sources until the spot disappears. |
6B10.35 |
Bunsen grease-spot photometer |
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A grease spot disappears when illuminated equally from both sides. Diagram of a grease-spot box. |
6B10.40 |
Rumford photometer |
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Light sources are moved until their shadows of the same object are of equal intensity. |
6B10.40 |
Rumford shadow photometer |
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Two light sources are moved so the shadow cast by a vertical rod is of the same intensity. |
6B10.50 |
frosted globe - surface brightness |
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The surface brightness of a 40 W bulb is compared to a frosted globe placed over it. |
6B10.50 |
surface brightness |
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A lamp with measured candlepower is enclosed in a frosted globe. |
6B10.60 |
surface brightness of a lens |
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Place the eye at the image point of a lens focused on a dim lamp. |
6B10.65 |
reflected surface brightness |
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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 |
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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 |
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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
PIRA # |
Demonstration Name |
Subsets |
Abstract |
6B30.10 |
radiometer - quartz fiber |
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6B30.10 |
radiation pressure |
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Construction details for a quartz fiber radiometer. Deflection of one radian is easily achieved with a microscope lamp. |
6B30.10 |
radiometer |
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The deflection of a quartz fiber radiometer is measured statically under high vacuum. |
6B30.11 |
radiometer |
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Focus a beam of light intermittently on a vane of the quartz fiber radiometer at the frequency of oscillation. |
6B30.20 |
light pressure comment |
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Brings attention to a paper that devotes six pages to describing errors in the "classical work by Nichols and Hull". |
6B40. Black Bodies
PIRA # |
Demonstration Name |
Subsets |
Abstract |
6B40.10 |
variac and light bulb |
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Vary the voltage to a 1 KW light bulb with a variac to show color change with temperature. |
6B40.10 |
variac and light bulb |
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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 |
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Holes in black boxes are blacker than the boxes. One box is painted white inside. |
6B40.20 |
hole in a black box |
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A box painted black has a hole in the side. |
6B40.20 |
Bichsel boxes |
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Two black boxes have blacker appearing holes in them. One box actually is painted white inside. |
6B40.25 |
carbon block |
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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 |
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A iron ball with a hole is heated red hot. |
6B40.26 |
carbon rod |
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Bore a hole in an old carbon arc rod and heat electrically. The hole glows brighter. |
6B40.30 |
radiation from a black body |
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Heat red hot a carbon block the has both a drilled hole and a white porcelain plug. |
6B40.30 |
carbon block and porcelain |
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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 |
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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 |
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An electric element (E-171) with chalk marks or china with a pattern are heated until they glow. |
6B40.40 |
X-Y spectrum recorder |
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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 |
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6B40.41 |
plotting the spectrum |
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Measure the output of a thermopile. as it is moved across a spectrum. Monochrometer in appendix, p. 1362, Plots. |
6B40.41 |
radiation intensity curve |
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Explore the energy distribution of the continuous spectrum of a carbon arc with a sensitive thermopile. and galvanometer. |
6B40.41 |
infrared in spectrum |
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Hold a thermopile. connected to a galvanometer in different parts of a spectrum. |
6B40.42 |
mapping the spectrum |
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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 |
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6B40.50 |
IR camera and soldering iron |
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6B40.55 |
project sprectrum and change temperature |
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6B40.55 |
radiation vs. temperature |
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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 |
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Project the spectrum from a projector lamp and change the voltage. |
6B40.62 |
Stefan-Boltzman equation |
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Measuring sigma by the relative method using a Hefner lamp as a standard radiator. |
6B40.70 |
microwave blackbody |
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Microwave radiation emitted or absorbed by a cavity is detected and displayed on an oscilloscope. |