Lab Report # 5 PDF

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Lab report for Ph 112...

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Lab # 5: Determining the Physical Size of the Sun Purpose: To become familiar with angular diameter. To find the sun’s physical and angular (Alpha-Greek letter α) diameter. Method: The apparent size of object depends on the distance. Perspective is the effect that objects appear smaller as they recede. A pinhole camera was used to find the angular diameter of the sun. Then we measured the length of the tube and the width of the sun’s image. Once we found those two measurements, we used the right triangle relationship which is the tangent (0.5a) = radius/distance to get the final result. The video method required the use of a formula. The formula consisted a proportion of the sun’s angular diameter divided by 360 degrees equal to the average length (in seconds) divided by 86,400 seconds. Using this proportion, we were able to find the angular size. After finding the angular size, we used the right triangle relationship to find the final results. Final Results: The estimated angular diameter from part 1 was 5 degrees however the actual angle was 10 degrees. Using the cross staff, we found the angular diameter of the plate which was 6 degrees. Using the right triangle relationship we could the radius. 0.052 x 200cm = 10.4cm. The diameter =20.8cm. The actual radius was equal to 11.5cm. 10.4 - 11.5/ 11.5 x 100 = 10%. We probably made an error in measuring the angle because our percent difference was more than 5%. The final results from using the pinhole camera was .6 degrees. The final results from the video method was more accurate because the sun’s image is not sharp. To find the sun’s physical size, we used the triangle relationship of 0.0052 x 150,000,000km = 780,000km x (2x the physical radius) = 1,560,000. Making the sun 121 times larger than Earth....