Abstract:
With the greenhouse effect and global warming in the science news spotlight, scientists around the world are focusing on the global energy balance to unravel key questions. The global energy balance involves the study of the flow of energy into, through and out of the earth system. You have already calculated solar surface irradiance (the solar surface energy emission). You will now work to calculate the solar constant, how much of that energy actually makes its’ way to the top of the earths’ atmosphere. As you work you will be asked to answer problems that scientists encounter in calculating the amount of energy that the earth receives from the sun.

Outcomes:

• Students will explain how the inverse square law effects the amount of solar radiation that reaches the earth.
  
• Students will calculate the solar constant.
  
• Students will calculate the percentage of solar radiation output reaching the earth.
  
• Students will calculate and compare variations in the solar constant from aphelion to perihelion positions in the earths’ orbit.
  

Suggested Grade Level & Duration:
Grades 9-12; 1 fifty-minute period.

Materials:
Calculator
Worksheet
Pencil