Materials:

• Weather Data (provided by teacher)
• Graph Paper and Colored Pencils or Crayons, Graphing Software (e.g., spreadsheet), blank graphs provided with the sample data
• Computer to obtain sunrise and sunset data from the U.S. Naval Observatory (http://www.usno.navy.mil)
  

Procedure:

1a. Make a bar graph of temperature values. For each hour, color the temperature value in red.

1b. On a second graph, make a bar graph of the relative humidity values in green.

With your teacher's permission, you may use a spreadsheet program like Excel to make the graphs.

2. Determine the sunrise and sunset times for your station for the day of your observations. One easy way to get sunrise and sunset times is from the U.S. Naval Observatory (http://www.usno.navy.mil). Mark the sunrise and sunset times on your graph. Shade the daylight hours on your graph in light yellow.

Questions:

1. Write a short paragraph to describe the temperature graph. In your paragraph, make sure you answer these questions:

• Did the temperature warm or cool before sunrise?
• Did the temperature warm or cool in the morning (between sunrise and 12 PM)?
• Did the temperature warm or cool in the afternoon (between 12 PM and 6 PM)?
• What was the high (warmest) temperature?
• When did the warmest temperature occurr?
• What was the low (coolest) temperature?
• When did the coolest temperature occur?

2. Write another paragraph to describe the relative humidity graph by answering these questions:

• Did the relative humidity increase or decrease before sunrise?
• Did the relative humidity increase or decrease in the morning (between sunrise and 12 PM)?
• Did the relative humidity increase or decrease in the afternoon (between 12 PM and 6 PM)?
• What was the highest relative humidity value?
• When did the highest relative humidity value occur?
• What was the lowest relative humidity value?
• When did the lowest relative humidity value occur?
• Compare the relative humidity graph to the temperature graph. Are they both high at the same time, or is one graph high when the other is low?

3. Compare the first and last values of temperature and relative humidity. The "first" values are the values from midnight on the first day. The "last" values are those values from midnight the second day (24 hours later). Were the last values the same, higher, or lower than the first values?