Question Description



This field study will begin with the study of sea surface temperatures off the east coast of the United States.

Then, you will analyze a volcanic eruption. Mount Pinatubo’s eruption in 1991 was one of the world’s largest eruptions in the past 40 years. Located in the Philippines, the volcano introduced significant amounts of ash and gases into the atmosphere, enough to cool the temperature of the entire earth slightly over a period of 3 years.

Part 1: What Do These Images Reveal?


1.  From the list of materials for this lesson, click the image titled Gulf Stream 1. The image may open in a variety of programs. Use the application on your computer that best shows the image.

2.  Determine what area you are viewing. Some images have an information legend and key included; others may include geographic clues to the area shown. Look at the information included with the image. This is an image of the ocean temperature near the Atlantic coast of the United States, including parts of the states from North Carolina to New Jersey.

3.  Note that each color in this image represents data. Notice the colors closer to and farther away from the coastline. What trends do you see?

4.  From the list of materials for this lesson, click the image titled Gulf Stream 2. Consider the two images of the same general region, but further south along the coast. These images were taken several days apart in early September of 1999. What are the substantial differences between them? The first image is prior to the onset of Hurricane Dennis. The second was taken shortly after the hurricane.

Part 2: Analysis of Volcanic Eruptions


1.  Familiarize yourself with the location of Mount Pinatubo and the details of the eruption. Use the Internet. Determine the longitude and latitude of the volcano.

2.  From the list of materials for this lesson, click the image titled Mount Pinatubo 1. All images that you will open for Mount Pinatubo were taken after the main eruption of the volcano. Copy or save the first image. Open it in a program that allows you to zoom in on an image. For the rest of this exercise, it will be assumed that you are using the Paint program that many computers have in the accessories folder. You may choose to use a graphics program or other tool to accomplish the same tasks. For helpful tips on using Microsoft Paint to view images, see Instructions for Using Paint to Analyze Images.

3.  Compare the images and note how far the cloud traveled. To do this, note that the images have a longitude and latitude grid where the distance between each pair of longitude or latitude lines represents 10°. Consider that at different latitudes, 1° of longitude will not cover the same distance. At the latitude that you will note for the volcano, the circle of latitude (the east-west line that circles the earth) has a length that is 96.6% of the earth’s circumference (the earth’s circle of latitude at the equator), which is about 40,075 km. Since there are 360° of longitude, each degree of longitude is equal to the length of the circle of latitude at that point divided by 360. For the circle of latitude that passes through the volcano, each degree if longitude is equal to 108 km.

4.  Now that you have determined this scale, find the center of the cloud as best you can. Note what you consider the latitude and longitude of the center of the cloud. There will be variance between the location you choose as the center and what others may choose. Additionally, remember that each pixel is not a point but rather a large square that covers a significant area.

5.  Repeat this procedure for the other satellite images, Mount Pinatubo 2 and Mount Pinatubo 3. Since the cloud seems to be getting larger, it may be more difficult to determine its center, but use a point that is in the center of the white area on the image. These images do not have a grid as the first one did, so you will have to estimate the latitude and longitude to the nearest degree. Record your results in the table.

6.  Calculate the distance that the center of the cloud traveled from Mount Pinatubo. Assume that the distance north and south is negligible compared to the distance to the east and west. This can be calculated easily by determining the number of degrees longitude the center of the cloud moved and multiplying the result by 108 km, the number of kilometers in a degree.

Distance Traveled by the Gas Cloud of Mount Pinatubo

Date Latitude (°) Longitude (°) Distance traveled (km)
Position of the volcano
Center of the cloud on June 16, 1991
Center of the cloud on June 17, 1991
Center of the cloud on June 18, 1991

7.  Plot a graph of cloud distance vs. time.

Part 3: Closer to Home


1.  Download and install Google Earth. Use the Instructions for Downloading Google Earth to help with the process.

2.  Note that Google Earth will allow you to view the location where you live in detail. Perform an analysis of the different types of land usage that are exhibited. To do this, find an image that is centered on your residence and save it somewhere you will be able to find it easily.

3.  Open and zoom in on the image until it is pixilated. Microsoft Paint is a valuable tool for this, though you may use another graphics program for this analysis. For helpful tips on using Microsoft Paint to view images, see Instructions for Using Paint to Analyze Images. For your analysis, indicate the size of the area that you chose to use (for example, 250 pixels × 200 pixels).

4.  Determine the types of land usage in the image. Common land types are vegetation, roads, streams, and buildings. Feel free to include others as you need to.

5.  Determine the actual area of a pixel in square meters.

6.  Determine the percentage for each land type in your region.

Land Usage around Your Residence

Land type Size of area for land type (number of pixels) Total number of pixels in sample Percentage



1.  In Part 1 of the field study, you qualitatively compared images of sea surface temperature data. Discuss how remote sensing, in this case, was more valuable than other kinds of data collection, citing at least two ways in which remote sensing was a superior form of data collection.



2.  In Part 2 of the field study, you studied the path of the cloud of gases and other substances spewed by Mount Pinatubo. Submit your data table and one sample calculation where you determined the distance traveled by the cloud. Also, submit the graph that you created of distance of the cloud center over time.


3.  In Part 3 of this field study, you determined percentages of land use around your home. Would you describe the area in your study as diverse? Support your answer with your data and submit your data table.



1.  Three hypotheses—ecocide, rat outbreak, and climate change—are candidates as explanations of why the society of Easter Island collapsed. Explain each hypothesis, present at least one piece of evidence for each one, and state a lesson that each hypothesis contains for the world today. For each hypothesis, write one paragraph of at least four lines



2.  In a paragraph, describe the seven steps of the scientific method.



3.  Error in data analysis often occurs because the researcher has chosen an inappropriate sample for study—a sample that does not correctly reflect the characteristics of the population or phenomenon as a whole. Name at least three different causes of sampling error and state why each of them can produce invalid data