LAB # ______ The Paths of the Sun

Problem

How can we determine:

 the location of sunrise and sunset on the equinoxes and solstices and

 the altitude of the noon sun on the equinoxes and solstices?

Materials

            Clear plastic dome

            External Protractor & Large round protractor

            Marking Pens 

Procedure

1.      Using the large, round protractor mark North, South, East and West on the rim of the globe.

2.      Draw in the observer’s meridian (a line from Nà S through the zenith).

3.      Put a dot on the meridian 48.5^o above the horizon (use the external protractor) to show the noontime position of the sun on the equinox.

4.      Put  dots on the rim of the dome at azimuths 90^o and 270^o  showing the location of  sunrise and sunset on the equinox.

5.      Draw a smooth blue line on the dome to show the path of the sun and label the line Sept 23 and March 21 (the two dates of the equinox).

6.      Put a dot on the meridian 25^o above the horizon to show the noontime position of the sun on the winter solstice.

7.      Put  dots on the rim of the dome at azimuths 125^o and 235^o showing the location of  sunrise and sunset on the winter solstice.

8.      Draw a smooth  green line on the dome to show the path of the sun and label the line Dec 21 (the date of the solstice).

9.      Put a dot on the meridian 72^o above the horizon to show the noontime position of the sun on the summer solstice.

10.  Put  dots on the rim of the dome at azimuths 55^o and 305^o  showing the location of  sunrise and sunset on the summer solstice.

11.  Draw a smooth red line on the dome to show the path of the sun and label the line June 21 (the date of the solstice).

12.  On diagram #1 draw  and label the path of the sun on June 21, Sept 23, Dec 21 and Mar 21.  Do the equinox path in blue, the summer solstice path in red and the winter solstice path in green.

Summary Questions

1.In which direction does the sun rise on: May 15? ________   Oct 1? ___________

June 30? __________  Your birthday? Date _______    Direction ____________

2.In which direction does the sun set on: May 15? ___________   Oct 1? ___________

June 30? __________  Your birthday? Date _______    Direction ____________

3.What is the highest noontime altitude that the sun attains all year in Newburgh? _______

4.The noontime sun is always found in what direction? _______________

5. On the equinox, sunrise occurs at __________AM and sunset occurs at  _________PM.

6.On the equinox path on the globe, mark the location of  10:00 AM.  Draw this on diagram #1.

7. On the equinox path on the globe, mark the location of  3:00 PM.  Draw this on diagram #1.

8. Why are Mar 21 and Sept 23 called the equinoxes? __________________________________________________________________________________________________________________________________________________________________________________________________________

9. Why are the first days of summer and winter called the solstices? ______________________________________________________________________________________________________________________________________________________________________________________________