Purpose: To provide an activity for a Science Fair Project to measure the size of the Sun.
Objective: To construct a pinhole viewer and gather data to effectively use the formula
for finding the diameter of the Sun.
Materials: Sun, Cardboard, tape, ruler, plain white paper, tin foil, pushpin, scissors
Procedure: 1) Construct a pinhole viewer.
Cut a 2x2 centimeter square in a piece of cardboard.
Tape a piece of tin foil over the opening.
Use a pushpin and puncture a hole in the tin foil.
2) Use your pinhole viewer to project the image of the Sun on a plain sheet of
white paper. Make the distance between the pinhole and paper as large as
possible and still have a sharp image.
3) Measure the diameter of the image of the Sun.
4) Measure the distance from the pinhole to the paper.
Observation: Diameter of the image of the Sun = ______
Distance from pinhole to paper = ______
Diameter of the image of the Sun X Distance from Earth to the Sun = Diameter of the Sun
Distance of pinhole to paper
%error = Correct Value – Experimental Value X 100%
Conclusion: The diameter of the Sun can be calculated from using a pinhole viewer and
using the above formula.