Download Discover Magazine: Chemical Detectives

TITLE OF VIDEO:
Discover Magazine: Chemical Detectives
VIDEO COMPREHENSION QUESTIONS:
1. Why did the military send sand samples from the balloon bombs
to the U.S. Geological Survey?
2. Why were some sand grains studied under a polarizing microscope?
3. Why were the balloons that were discovered in the northwestern part of the United States so
unique?
4. If scientists identify materials from a fire as containing accelerant, why do they immediately
put the materials in sealed containers and send them to a lab for analysis?
5. How many times greater is a dog's sense of smell than a human's?
6. What talent, beyond a superior sense of smell, allows arson dogs to be so successful at their
jobs?
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See next page for answers.
Discover Magazine: Chemical Detectives
VIDEO COMPREHENSION QUESTIONS AND ANSWERS:
1. Why did the military send sand samples from the balloon bombs
to the U.S. Geological Survey?
The military sent these sand samples to the U.S. Geological Survey because they wanted the
geologists there to pinpoint the location from where the sand came.
2. Why were some sand grains studied under a polarizing microscope?
A polarizing microscope allows scientists to see a range of different colors in something they are
studying. When geologists studied sand grains with this kind of microscope, the colors that appeared
helped them determine the sand's mineral content.
3. Why were the balloons that were discovered in the northwestern part of the United States so
unique?
These balloons were unique because of their simplicity. In a time of increasingly sophisticated
weaponry, these balloons were made from only rice paper and vegetable paste.
4. If scientists identify materials from a fire as containing accelerant, why do they immediately
put the materials in sealed containers and send them to a lab for analysis?
Materials containing accelerant evaporate very quickly. A sample must be analyzed fast, before any
identifiable accelerant is gone.
5. How many times greater is a dog's sense of smell than a human's?
A dog's sense of smell is more than 100,000 times greater than a human's.
6. What talent, beyond a superior sense of smell, allows arson dogs to be so successful at their
jobs?
Dogs have the ability to discriminate among different odors. This allows them identify accelerant
even when it is mixed with other strong smells.
DiscoverySchool.com
http://www.discoveryschool.com
Copyright 2002 Discovery.com.
Teachers may reproduce copies of these materials for classroom use only.