Solar Gnomon Lab Part 2

Here I will be showing you how I did this lab. I collected my data on March 3, 1996. You will find data tables and examples of the math.
 
 
 
Time
Shadow Length
Altitude of the Sun in degrees
11:30AM
9.1cm
47.69
11:45AM
8.4cm
49.96
12:00PM
8.0cm
51.34
12:15PM
7.6cm
52.76
12:20PM
7.5cm
53.13
12:25PM
7.48cm
53.20
12:30PM
7.45cm
53.31
12:35PM
7.41cm
53.46
12:40PM
7.45cm
53.31
12:45PM
7.5cm
53.13
12:50PM
7.55cm
52.94
1:05PM
7.70cm
52.40
1:20PM
8.0cm
51.34

The data table has been filled out with the computed altitude for the Sun at each time interval. Follow the example for the calculation part to see how I arrived at the computed altitudes.
 

Gnomon height is 10cm

Example from data table above.

(11:30AM) 10cm/9.1cm = 1.0989, then hit INV TAN or SHIFT TAN and the result will be 47.69 degrees. Pretty straight forward math. Be careful how you enter the data correctly. The gnomon height divided by the shadow length equals the tangent of the altitude. Then INV TAN equals the altitude.

If you look at this data table you will notice that on the the date I took the data we were nearing the Spring Equinox, so the altitude was nearing 60 degrees. Remember that to find the altitude of the celestial equator, you take 90 degrees minus your latitude. For Huntsville it is 90-30 equals 60 degrees. Do you see the correlation in the data table?

Now that your data is complete, go ahead and plot your results on a piece of graph paper. Do your altitude plot on the "y" axis and time plot on your "x" axis. For the time being, stop right here and bring your graph, data table and gnomon board in for me to look at.
 

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