Name:_________________________



Name:_________________________ Period:__________

Partners name: __________________

Adapted from:

Internet Lab: Suns Path

Introduction:

The sun’s path is an apparent path across the sky. Each day, the sun appears to move in

an arc across the sky at a rate of 15°/hour (360 degrees in 24 hours), the rate that the Earth rotates on its axis. This rotation makes it appear that the sun is moving from east to west. The daily motion of the Sun, therefore, is not real but apparent. This daily apparent path of the sun changes with the seasons because the earth is revolving around the sun. The sun is at its highest point at Solar Noon.

In this lab, you will use the Sun Path JAVA applet at   to visualize the apparent position of the sun as seen by an observer on Earth. Remember, the sun is not rising or setting but appears to be so due to the Earths rotation.

1. For simulation type select yearly, month January, day 21, hour noon and latitude for your city

(Use 42.53 for Buffalo, NY which is really 42° 53’ N).

2. Run the yearly simulation by clicking on the forward play button.

3. Press the arrow all the way up for a better view of the sun from the horizon. Reset the month to January and repeat step 2 from this different view.

4. In your own words, describe how the suns position at noon changes relative to the horizon over the course of a year. (You can use the rewind button to look at the suns path again if needed).

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5. Fill in the table below for altitude of the sun at noon for each month (suns angle above horizon, found in the top right hand corner of the animation), sun-rise and sunset times (bottom right hand box of animation), the length of day between sunrise and sunset, and If you need help calculating the length of day, use the length of day calculator linked to our website. Hint: Use the forward play to scan through for sunrise times and the backward play to scan back for sunset times or use the step play buttons. To save time, some of the values have been filled in for you.

|21st of each Month |Altitude of Sun in |sunrise (hr:min) |sunset  (hr:min) |length of day  |

| |Degree | | |(hr:min) |

|Jan |27.33 |7:18 |16:41 |9:23  |

|Feb |  |  |  |  |

|Mar | |  | | |

|Apr |  |  |  |  |

|May | | | | |

|Jun |  |  |  |  |

|Jul |  |  |  |  |

|Aug |  |  |  |  |

|Sep |  |  |  |  |

|Oct |  |  |  |  |

|Nov |  |  |  |  |

|Dec | |  |  |  |

Press the arrow for a better view of the shadow produced as a result of the sun moving across the sky

6. When do you have the longest shadow at noon (Is the sun high or low in the sky, circle one)?

7. What month does this occur? __________________

8. When do you have the shortest shadow at noon (Is the sun high or low in the sky, circle one)?

9. What month does this occur? __________________

10. What time does the yellow sun first appear? __________

11. What time is the yellow sun last visible? _____________

12. How many degrees does the sun move each hour? _________

13. Is the shadow at noon bigger or smaller than the noon shadow on June 21? _______________

Now change the Month to June and reset the hour to Midnight- Repeat changing the hours.

14. What time does the yellow sun first appear? __________

15. What time is the yellow sun last visible? _____________

16. How many degrees does the sun move each hour? _________

17. Is the shadow at noon bigger or smaller than the noon shadow on January 21? _______________

18. What times is the shadow the longest? __________ and ___________

19. What time is the shadow the shortest? _______________________

Below is a graph of the data you just gathered, length of daylight in hour’s verses month of year. Use this graph and your knowledge of Earth Science to answer the following questions.

20. In the Northern Hemisphere what month and day has the shortest amount of daylight? ______________

21. What is the special name given to this day? _______________________

22. In the Northern Hemisphere what month and day has the longest amount of daylight? ______________

23. What is the special name given to this day? _______________________

Below is a graph of your data for the sun’s altitude in the sky verses the month of year. Use this graph to answer the following questions.

24.  The altitude degree tells you how high the sun is in the sky relative to the horizon. What month is the sun highest in the sky at noon at our latitude? ____________.

25. What month is the sun lowest in the sky at noon? ____________________________

Using both graphs and your knowledge of Earth Science, answer the following questions.

26. Are noontime shadows getting longer or shorter in July?______________________________

27. Do days get longer or shorter in November? _________________________________________

28. Is the sun rising or falling each successive day at noon in January? _______________________

29. Is the sun rising or falling each successive day at noon in May? _________________________

30. Do days get longer or shorter in March? _____________________________________________

How does the noon Sun’s altitude change from: June to December?

a. June to December? _______________________________________________________

b. December to June _______________________________________________________

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Altitude: the suns angle above horizon. 

Azimuth: Where on the horizon the sun rises.

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Now go to January 21st - set the hour to midnight- Now keep changing the hours one hour at a time. (Hint- With the hour highlighted, the down button on your key pad will move the hours)

42.53

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