• Explain and demonstrate how the earth's rotation causes day and night.
• Interpret information presented in table form.
• Explain how changing amounts of solar energy during the day and night is a reason for temperature change.
• Deduce a cause/ effect relationship from given data.

• Globe
• World Map
• Flashlight

• Background Information:  Radiant energy from the sun is a reason for temperature changes. Much of this sunlight is absorbed by matter on earth and changed to heat,  warming the air above it.  This continues throughout the day, so afternoon temperatures are usually the warmest.  At night, when the sunlight does not strike the earth, much of the earth's heat energy is radiated back into space.  No sunlight is being absorbed and changed into heat. So the temperature drops at night and is still low in the early morning. As the sun rises, its rays strike the earth more directly . 
  Cloud cover also has an effect because clouds act like a blanket on the earth keeping it from losing heat. Clouds can also cool the daytime temperatures by blocking the sun. Temperature changes during the day and night can be great or small depending on the cloud cover. Clouds blanket the earth and keep it from loosing heat. 

• Bookmark and become familiar with the following sites:
  Weather Underground Historical Conditions are accessed via the drop-down menu situated below Current Conditions.
  Earth Viewer
  The Official US Time 

1. Lead the class in a simple rotation simulation to demonstrate what causes day and night. Put a piece of paper on a globe to mark your location. One student will hold the globe and another the flashlight to simulate the sun. Have the student holding the globe  spin it counterclockwise. Have the students identify places on the opposite side of the globe that will be having night while they are having day. They should make the observation that, as the earth rotates, new parts of it come into the sun's light.
2. Have students  go to Earth Viewer, a map of the earth showing the current day and night regions.
   Ask: 

• Which part of the world is experiencing night right now?
• Which part is experiencing day?
• Where is the sun rising and setting?
  

3. Use the class room map to find some of the countries in these locations.
4. Access  The Official US Time and have students find their location and time zone. Ask: 

• Could it be daytime in one part of the country and night time in another?
• Explain why or why not.
• Where does the sun rise first,  New York City or San Francisco?
• How do you know?

Activity#2 Highs and Lows
For this activity, do the following:

3. Tell the students that this site will have the high and low temperatures for today available for viewing tomorrow and that they are going to try to predict at about what time of day those temperatures will occur by looking at previous data.
4. Go to the Weather Underground.  Access historical conditions to view the data from the previous day.  Look at the high and low temperatures for the day and then check on the chart on the bottom to find out at what time they occurred. Students should record the high and low temperatures and the times they occurred.
5. Students should then use the site to access the weather data from the last five days. They should record the high and low temperatures and the times they occurred. Ask whether or not they notice any pattern in the data. (The students will discover that the highest temperatures usually occur in the afternoon and the lowest between midnight and dawn).
6. Students will predict the approximate times that the current day's high and low temperatures will occur.