Pinhole Camera Experiment:
Dante Tufano
Materials:
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Pinhole camera
o Index card
o Aluminum foil
White paper (screen)
Ruler
Scissors
Pin/Needle
Tape
A black board with an index card-sized hole
Procedure:
Making the Camera:
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Cut a square hole about 2 x 2 cm in the center of the index card.
Tightly cover the hole with aluminum foil and tape the foil onto the index card.
Use a pin or needle to poke a hole in the center of the aluminum foil square.
You have a pinhole camera! (kind of)
Part I: Determining the diameter of the sun and moon.
1. Mount the black board in front of a window and mount the pinhole camera onto the hole
in the board such that light only enters the classroom through the pinhole.
2. Mount a sheet of white paper (screen) in front of opening of the pinhole camera.
3. Adjust the position of the screen until an image of the sun is visible. Record the distance
of the screen from the camera as well as the diameter of the image.
4. Then, using the equation:
𝐷𝑠 =
𝐷𝑖𝑎𝑚𝑒𝑡𝑒𝑟 𝑜𝑓 𝑡ℎ𝑒 𝑆𝑢𝑛 ∗ 𝑑
𝐷𝑖𝑎𝑚𝑒𝑡𝑒𝑟 𝑜𝑓 𝑡ℎ𝑒 𝑖𝑚𝑎𝑔𝑒
where Ds is the distance of the earth from the sun and d is the distance from the camera to
the screen, find the distance of the sun to the earth given the diameter of the sun. How
well does this value agree with the actual value?
5. Repeat step 4 to determine the distance of the earth to the moon given the diameter of the
moon. Use the same image diameter as in step 4. How well does this value agree with
the actual value? If this value does not agree, what may be the cause of error?
Part II: Examining the trajectory of the sun
1. Mounting a screen in front of the pinhole camera as in Part I, mark the position of the
sun’s image on the screen.
2. Continue to mark the image’s position of the screen at fifteen minute intervals.
3. Measure the distance between each image position on the screen.
4. Calculate the average speed of the image across the screen.
5. Using the equation from step 4 of Part I, determine the average speed of the sun’s
apparent movement through the sky.
6. Look up the speed of the Earth’s rotation. Does the answer determined in step 5 agree
with this value?
Note: This experiment would work well as an astronomy lab, and could also be used as an
Analytical physics lab with the inclusion of more complex analytical questions.
Kepler’s Work on Optics:
Though Kepler is a man renowned for his laws of planetary motion, his other work,
especially his work with optics, is tremendously understated. In the preface to his Optical Part
of Astronomy, Kepler describes how he wished to “lead the optical science through to that degree
of subtlety that it might satisfy the astronomer” (Kepler 5). It is important to note that Tycho
Brahe’s death is cited as a major influence on the time of this work’s publication (Astronomiae
Pars Optica 7). In the body of his Optical Part of Astronomy, Kepler proceeds to
mathematically describe how each type of lens functions, both by itself and when coupled with
the human eye. Kepler also describes several known telescopes of the era as well as the
Keplerian telescope, which was not yet existent. As it was, Kepler’s work on optics completely
revolutionized the field, and he is considered by many to be the father of optics as it is known
today. This experiment is meant to pay homage to that fact.