PHGN-398A Fall
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-use Archimedes principle to measure displacement and therefore volume. Density gives mass. | -use Archimedes principle to measure displacement and therefore volume. Density gives mass. | ||
| − | -use laser imaging to see how much rock is removed from the quarry daily. | + | -use laser imaging to see how much rock is removed from the quarry daily. |
Revision as of 00:46, 29 September 2010
| Main Page | > | Physics Course Wikis |
Course Information
Instructors: Vince Kuo, Patrick Kohl and Frank Kowalski
Course Links
Creativity in Science and Engineering
PROBLEM 1: Measuring the wavelength of an unknown laser: What apparatus would you use to measure the wavelength of an unknown laser using a He-Ne laser whose wavelength is know to 8 significant figures?
Green Hat comments
Apparatus:
-two slit interferometer -Superimpose the two laser beams with a beam splitter. Look at the time dependent detector output for beats and take a Fourier transform.
-Superimpose the two laser beams with a beam splitter then shine them on a grating. Look at the spatial separation.
-Superimpose the two laser beams in a Michelson interferometer. Then measure constructive interference of each color and compare.
-Superimpose the two beams and shine them into a parallel plate device (Fabrey-Perot) interferometer. Vary the plate spacing and compare the maxims observed.
-Shine the two beams in a "funnel" absorbing chamber and look for where each is extinguished.
-Cross the two beams at a known angle and look for the spacing of the fringes.
-Measure the combined color of the two beams together.
-Measure standing waves in a cavity whose size is changed.
-Use a dielectric material with a known index of refraction to measure cause a know phase shift and measure its effects.
-Look at the diffraction pattern as both beams traverse a single slit interferometer.
-Beat Frequency
-Diffraction Patterns
idea taxonomy comments
taxonomy A
idea 1 of using diffraction. Fluency involves a single slit, a double slit, a grating . . .
idea 2 of using an interferometer. Fluency involves a Michelson interferometer, Fabry-Perot interferometer, . . .
idea 3 of measuring the beat frequency. Fluency involves combining the waves in a detector and measuring the beat, . . .
taxonomy B
combining ideas comments
questioning/observing comments
-What has the best resolution (yields the most sig figs)?
-What is easy to align?
analogy comments
reminding comments
anomaly comments
White Hat comments
Descriptions of grating spectrometer are found at these two links:
The resolution of a grating spectrometer, or the smallest change in wavelength measurable divided by the wavelength is the order number times the number of grooves illuminated, which is about 1 part in 2 for a double slit "grating" and about 1 part in 10,000 for an expensive spectrometer. This is discussed in the following link:
A Michelson or Fabry-Perot interferometer has a change of a fringe every time one mirror is moved half a wavelength. For a mirror motion of 1 meter the number of fringes for the He-Ne laser (wavelength of 6328 Angstroms) is 1.58 million fringes. How many fringes for the unknown laser if both beams were superimposed? How does this resolution compare with the grating spectrometer?
Black Hat comments
Yellow Hat comments
Red Hat comments
Blue Hat comments
Problem 2: Measuring the Mass Extracted from a Quarry
Green Hat comments
-measure the weight of the trucks carrying the material out of the quarry.
-measure the effect of mass loss on the gravitational attraction.
-measure the volume extracted and determine the mass from its density.
-measure the flow rate of material on a conveyor belt.
-use fuel consumption in the trucks to measure energy required to move the mass.
-measure the mass as it is loaded on the truck via a scale on the scooper truck.
-use Archimedes principle to measure displacement and therefore volume. Density gives mass.
-use laser imaging to see how much rock is removed from the quarry daily.
idea taxonomy comments
taxonomy A
idea 1 of using a scale to weigh the rock. Fluency involves weighing a truck, weighing the machine which picks up the rock, . . .
idea 2 of using fuel consumption in moving the rock. Fluency involves measuring the gas used by a truck over a known trajectory, . . .
idea 3 of measuring the volume remove. Fluency involves using a laser ranging system to map the quarry before and after . . .
idea 4 of measuring the flow rate. Fluency involves using a conveyor belt and monitoring the volume of rock that flows, measuring the flow rate on some slide that the rock moves down, . . .
taxonomy B
One main idea: measuring volume. Fluency involves the volume of rock, volume of gas used by the truck, or volume of rock removed.
combining ideas comments
Fluency: I think there are basically 3 ideas, and not much originality
-Weighing with scale.
-Volume displacement with mass density.
-Flow rate.
questioning/observing comments
-How are rocks removed? Air hammer, dynamite, . . .
-How are rocks moved? Trucks, . . .
-What changes when rock is moved/removed?
-How can we detect that change?
analogy comments
reminding comments
anomaly comments
White Hat comments
Black Hat comments
Yellow Hat comments
Red Hat comments
Blue Hat comments
Problem 3: How could you convert wind energy into a useful form using a non-turbine (non-propeller) device?
Green Hat comments
-large balloon to convert elastic energy into useful energy.
-cones to funnel the wind into a region where it moves faster.
-use ribbons which jiggle in the wind to capture the wind energy.
-kite to capture wind energy.
-wind pushes cart attached to piston.
-sail moves wire through a magnetic field to generate electricity.
-wind pushes magnets through a coil to generate electricity.
-use cool air and warm earth to get a temperature differential for the thermoelectric effect.
-use a "water wheel" device but with wind rather than water moving it.
-use wind chill factor wind has for a temperature differential and the thermoelectric effect.
-wind rug (needs more explanation).
-streamers attached to a device which converts their motion to electricity.
-wind through a funnel and onto a "water wheel" type of device.
-convert the energy of whipping flags.
-concentrate the wind in a pipe and use it to stoke a fire.
-use the drag force of the wind on a stationary object to generate heat and convert the heat to electricity.
-use the wind to trigger potential energy in a system (rock slide).
idea taxonomy comments
taxonomy A
taxonomy B
Some common themes in our ideas:
-Driven oscillators
-Magnetic induction
-Solid state devices
-Evaporative cooling
-Wind pressure magnification
combining ideas comments
-The rug and thermoelectric ideas could be combined to make an extremely high surface area thermoeletric crystal "forest."
questioning/observing comments
-What generates wind?
-What absorbs wind?
-Wind moves faster higher off the ground. Could the velocity gradient be used to generate electricity (like the temp. gradient is used in thermoelectric effect)?
-The thermoelectric effect appeared several times, but the piezoelectric effect wasn't suggested once. Could piezoelectric materials be useful?
- What's the Piezoelectric effect?***
-Perhaps the energy of tornado winds could be harnessed somehow
analogy comments
Just like solar concentrators can generate extremely high light and temperature concentrations for i.e. pumping lasers and cooking food, wind concentrators might give us a way to do more high-power mechanical conversions (i.e. moving large volumes of water or compressing heavy pistons).
