Hints on Using the ALTA to take a Spectrum
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Buttons on the front are for_____
– What do the numbers stand for?
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LEDs on the back are for _____
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Need to HOLD DOWN the buttons to take readings with the LEDs on
•
What happens if you place the ALTA down flat and don’t turn on any of the
lights?
• You still have a number—ALTA’s photodetector and electronics don’t
go to zero. This is your “Dark Voltage”
•
Need a large flat surface if possible for more accurate readings.
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Begin with taking the data for two stacked pieces of white paper.
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Work in groups of 3: one to press the buttons, one to record the data, and
the third to do the calculations.
•
When taking readings of rocks try not to let outside light into the detector
(turn off the lights)
•
Take the data from the flattest part of the rock; if the rock has a side with
an unusual appearance, avoid that part.