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SCIENCE Spin from WEEKLY READER
Technology
Meltdown!
Few plants or animals live on the icy mountaintops in southern Argentina and Chile.
This South American region is cold, desolate, and snowy and has dozens of
glaciers. These glaciers, many of which are in the Andes Mountains, are in danger
of melting away.
The glaciers in South America are some of the largest outside of the polar regions.
Because of the region's rough terrain and harsh weather, scientists have trouble
reaching the area by foot. To study the melting of the South American glaciers,
scientists recently used satellite technology.
Slipping Away
Scientists used satellites to take pictures of the glaciers. Those pictures were compared
with earlier information. What scientists found was that the glaciers in this area are
rapidly melting. In fact, they are melting twice as fast as they were just a few years
ago. Erik Rignot, an expert who studied the glaciers, referred to the South
American ice fields as the "fastest area of glacial retreat on Earth."
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FROSTY FACTS
Glaciers are large sheets of snow and ice that move slowly over land. Glaciers are
found in the polar regions around the world and in mountain valleys.
As the glaciers in South America, and in other parts of the world, retreat, their water
flows into lakes or oceans. As a result, the meltdown is causing levels of Earth's
oceans to rise. If ocean levels rise by even a foot, coastal cities around the world
could be flooded.
The Heat Is On
What is causing the glaciers to pull a disappearing act? Warmer temperatures and less
snowfall are to blame for the meltdown, say scientists. The warmer temperatures
cause the glaciers to break off into the ocean as icebergs. That process, called
calving, has increased in recent years. It's not just that the South American glaciers
are on thin ice. Scientists warn that about 90 percent of the world's glaciers are
melting from global warming.
Think About It
1. How do you think a glacier might shape the Earth's surface?
2. What other surface features of Earth could scientists use satellites to study?
Find out more! Log on to www.hspscience.com
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SCIENCE Spin from WEEKLY READER
People
Looking Beneath the surface
Florence Bascom was one of the first women in the United States to enter the field of
geology. Geology is the study of rocks, rock formations, and the structure of Earth.
In 1896, Bascom became the first woman to be hired by the United States Geological
Survey. Bascom studied how mountains formed, and she became an expert in the
study of crystals, minerals, rock composition, and landforms. She focused a lot of
her attention on the Piedmont—foothills—east of the Appalachian Mountains,
some of the oldest mountains in North America.
Bascom was also one of the first American geologists to use microscopes to study the
composition of rocks and minerals.
Career Geologist
Geologists study the makeup, changes, and history of Earth. They also try to understand
how rocks were formed and what has happened to rocks since their formation.
Many geologists are involved in searching for oil and gas, and others work closely
with environmental scientists in preserving and cleaning up the environment.
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SCIENCE Projects
for Home or School
You Can Do It!
Quick and Easy Project
Making Seismic Waves
Materials
 goggles
 spoon
 apron
 2 foam blocks
 9" x 13" cake pan
 sandpaper
 water
 masking tape
 food coloring
Procedure
1. CAUTION: Put on goggles and an apron. Pour 1 cm of water into the cake pan.
Add a few drops of food coloring. Mix with the spoon.
2. Tape sandpaper to one long, thin side of each foam block. Put the blocks in the water.
Push them together so the sandpaper sides touch.
3. Quickly slide the two blocks along each other in opposite directions. Observe what
happens to the water.
Draw Conclusions
What happens if you move the blocks more slowly? Describe how this model is similar
to moving plates in an earthquake.
Design Your Own Investigation
How Do Rivers Change the Land?
You know that rivers can change Earth's surface. Some rivers flow down steep slopes.
Other rivers flow over flat land. Design an investigation to see how the slope of the
land determines how a river changes Earth's surface. Decide what materials to use
to model the river and its banks. How will you change the slope of your model?
How does the slope of a river affect the way it changes Earth's surface?
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