Name: _______________________ Date: _____________ Class period: ________

## Student Worksheet

### Lesson: Graphs and the Composition of Earth's Thermosphere

Directions: After reading the background information, summarize the characteristics of the thermosphere in the space provided.

 Summary of thermospheric characteristics.

Directions: Study the graph, “Principal Constituents of the Thermosphere” and complete the data tables.

#### Data Table #1

Constituent
Name
Describe what happens to the density as height increases.
O

O2

N

N2

H

He

Directions: Refer to a Periodic Table of the Elements and the graph, “Principal Constituents of the Thermosphere” as you complete the information required in Data Table #2.

#### Data Table #2

Constituent
Atomic Mass
of Constituent
Maximum Density
(#/cm3)
Height of Maximum Density
(km)
O

O2

N

N2

H

He

### Analysis Questions:

1. The two variables being measured in the graph, “Principal Constituents of the Thermosphere” are Height (km) and Particle Density (#/cm3). Which variable is the independent and which is the dependent? (Remember the dependent variable “responds as the independent variable is changed".)

1. By convention, the independent variable is usually located on the x-axis of a graph. Carefully observe the graph, “Principal Constituents of the Thermosphere”. What do you notice about the independent variable and dependent variable?

1. Give a possible explanation for what you found in question #2.

1. In the table provided below, rewrite the list of thermospheric constituents in order of their atomic masses (smallest to largest).
 Atomic Mass Constituent
1. At what height(s) do the heavier constituents have their greatest density?

1. At what height(s) do the lighter constituents have their greatest density?

1. Give a possible explanation for what you found in questions 5 and 6.

1. In the background, it was stated, “…scientists can’t measure the temperature directly. They measure the density of the air by how much drag it puts on satellites and then use the density to find the temperature.” What are some possible reasons for the importance of knowing the density and the temperature of the thermosphere?

Last modified May 27, 2005 by Randy Russell.

The source of this material is Windows to the Universe, at http://www.windows.ucar.edu/ at the University Corporation for Atmospheric Research (UCAR). © 2005 University Corporation for Atmospheric Research. All Rights Reserved.