Patterns in the Day and Night Sky - Length of Day and Night

Georgia Perimeter College

Objectives  

  1. Describe and model changes and patterns in the day and night sky (day/night transitions) and changing length of day and night as related to changing seasons.
  2. Demonstrate an understanding of data collection (observation, measurement, recording, etc.), and the interpretation of data.
  3. Identify patterns of change using records, tables, or graphs of measurements.

Preassessment

Ask the class:

How many hours are in a day?
How many hours of daylight do we have? 
How many hours of night?

Materials

Activity

1.  How would we find out how many hours of daylight we have?  List several ways.

    ____________________________________________________

    ____________________________________________________

    ____________________________________________________


2.  Check times for sunrise and sunset today for the cities below and fill in the table.

Sunrise and sunset times for Georgia from the National Weather Service, Peachtree, GA http://www.srh.noaa.gov/ffc/html/srss.shtml

City Sunrise Time Sunset Time
Clarkston    
Savannah    
     
     
     

3. What do you notice about the times?

_________________________________________________________________________________

4.  Plot the locations of these cities and list the sunrise and sunset times beside them on the outline map of Georgia.

 

4. Choose at least three other cities in Georgia, and find their sunrise and sunset times.  You may use a map to choose the cities.  Fill in the table and plot them on the map.

5. Why did you choose these particular additional cities?

_________________________________________________________________________________

6.  Do you see a pattern to the times? _______________________

7.  Describe the pattern you see.

_________________________________________________________________________________

8.  Come up with an explanation for the pattern you observe.

_________________________________________________________________________________

_________________________________________________________________________________
 

9.  Choose one particular city in Georgia.  Let's see how sunrise and sunset times vary through the semester.  You can get your data from the U.S. Naval Observatory, Astronomical Applications, Data Services: http://aa.usno.navy.mil/data/

Day Sunrise Time Sunset Time Day Length Night Length
Aug 11        
Aug 18        
Aug 25        
Sept 1        
Sept 8        
Sept 15        
Sept 22        
Sept 29        
Oct 6        
Oct 13        
Oct 20        
Oct 27        
Nov 3        
Nov 10        
Nov 17        
Nov 24        
Dec 1        
Dec 8        
Dec 15        
Dec 22        
Dec 29        
Jan 05        
Jan 12        

10.  Now add data for day length and night length.

You can calculate the length of time between sunrise and sunset (day length), and the length of time between sunset and sunrise (night length), or you can use the website that has already done this for you at the link above.

11.  What do you notice about the length of the days?

_______________________________________

12.  What do you notice about the length of the nights?

_______________________________________

13.  Using a piece of graph paper, a pencil, and a ruler, plot a graph with day length on the vertical axis and dates across the bottom.  When finished, connect the dots.

14.  On the same graph, plot night length.  When finished, connect the dots.

15.  What do you notice about how the two lines you plotted relate to one another?

_________________________________________________________________________________

16.  Do the lines ever cross?  __________

If so, at what date? __________________________________

17.  What is the significance of this date?

_________________________________________________________________________________

18.  Does the line curve and change direction at any point?

If so, at what date? __________________________________

19.  What is the significance of this date?

_________________________________________________________________________________

20.  If you were to extend this investigation, what would you want to do next?

_________________________________________________________________________________

_________________________________________________________________________________

21.  What causes the changes you observe in the length of day and night?  What is going on??  Draw sketches to help you figure this out.

_________________________________________________________________________________

_________________________________________________________________________________

 

 

 

22.  What is an equinox?  What happens at that time?
http://aa.usno.navy.mil/faq/docs/equinoxes.html

_________________________________________________________________________________

_________________________________________________________________________________

23.  What is a solstice? What happens at that time?

_________________________________________________________________________________

_________________________________________________________________________________

21.  What could we do on campus during class in order to mark the changing position of the sun in the sky during the semester?

_________________________________________________________________________________

_________________________________________________________________________________

22.  How did ancient peoples mark the changing position of the sun in the sky?

 

 

 

 

 

Extension

Each student should plan to watch a sunrise (and/or sunset) one day each week throughout the semester. 

Procedure

Pick a place outside where you can see the horizon fairly clearly.  Note the exact place where you stand to make your observation. 

Draw a sketch of the horizon at that spot, noting features such as trees or buildings.  If you have a camera, it will be easiest if you photograph the horizon. 

Each week as you make your observation, write down the date and time of the sunrise or sunset. 

Plot the position of the sun on your sketch or photo of the horizon at your location.

Using a compass, record the compass direction (number of degrees east or west of north) to the position of the sun on the horizon.

Week Date Sunrise or sunset? Time Compass direction

1

       
2        
3        
4        
5        
6        
7        
8        
9        
10        
11        
12        
13        
14        
15        


 

 


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Content provided by Pamela Gore, Georgia Perimeter College

Page created by Pamela J. W. Gore
Georgia Perimeter College,
Clarkston, GA

Page created August 12, 2007
Modified August 29, 2007
Modified September 22, 2008