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Activity 4    F Box Explorations

1.      Set the light box at a distance from the lenses.  Turn on the light so that the letter “F” shines toward the lenses.

2.      Place graph paper screens behind the lenses and move the screens so that the image of the letter “F” can be seen clearly on each paper screen. 

3.      In turn, attach the aperture mask over the set of lenses. 

4.      Fill in the following chart using observations and measurements of the lenses and images produced.  Also record separately other observations that do not fit well into this chart.  Or, design your own way to record and organize your data.

5. Compare the data you have collected about the lenses and the images they make.  What changes about the image for different lenses?  What stays the same?   Use the terms aperture, image size, focal plane and focal length where appropriate.
    
6. Try to discover mathematical relationships which could be expressed as ratios or equations that seem to work with this data.  Record your ideas and whether or not they seemed to work with this data. 
   
   
7. Astronomers often describe a telescope with an f/ratio. The ratio is the focal length divided by the aperture.  Describe each lens with an f/ratio. 
   
   
8. The graph paper represents the pixels in a CCD camera.  The pixels are light collecting 'bins' in the camera detector. This is the way the camera records detail. So, if you were choosing, which pixel size as represented by the graph paper seems most appropriate for each lens?  Explain the reasons for your choices.