WHY ARE VOLCANOES DANGEROUS?
Many people think that volcanoes are dangerous because of the
lava that they eject. This may be due to the "Hollywood" impression
that we grow up with. We would like the students to understand that pyroclastic
outbreaks are one of the deadliest types of all volcanic activities. The
students will also learn to estimate size, speed and temperature by looking
for visual clues in a video.
3-2-1 Classroom Contact: Too Hot To Handle (#13)
Students will be able to:
- Describe a pyroclastic eruption.
- List the causes of an explosive volcanic eruption.
- List three major ways in which volcanic eruptions destroy people and
- Describe a lava collection technique used in a Hawaiian-type eruption.
- Estimate the effects of an eruption.
- State ways that human action or inaction can have a negative effect
on loss of life in an emergency or natural disaster.
- 2 sheets of paper and a pencil
- one potato chip bag
- one small balloon
- one pin
- large container of water
Tell students: As many as 40,000 people have been killed in
a single volcanic eruption. Hundreds of smaller eruptions have destroyed
many towns and caused the loss of thousands of lives throughout recorded
history. The town of St. Pierre on the island of Martinique was completely
wiped out when nearly all of its 40,000 residents were killed in a tragic
eruption of its volcano Mt. Pelee.
Ask the students to write down all the ways a volcano can destroy a town
and/or harm its residents. Allow a few minutes for the students to complete
Let the students take turns reading one item each from their lists and write
their answers on the chalkboard. After you have a list of 4 to 6 ways, ask
the students to work in groups of three and rank the ways from most destructive
to least destructive, and be able to explain why they listed them as they
did. List the new rankings on the board.
Say: We are going to perform a skit that will show a few of the reasons
that so many people were killed in St. Pierre. We will need 6 students to
be the lead actors in this skit. All of you will play the part of a citizen
of the city. Ask the students to read their parts in a brief skit depicting
a visit to the volcano's crater by the committee of leading citizens a few
days before the eruption.
Have students perform the attached skit: "What Really Happened At St.
To give the students a specific responsibility while viewing,
tell the students: List visual clues that you could use to determine an
approximate temperature range of the lava that is being collected in the
Continue: You must be able to recognize and list the effects the cloud of
material that was produced in the Mt. St. Helens eruption of 1980. Produce
a list of 4 or 5 ways that such a cloud could affect property and people
in its path. (Write this assignment on the chalkboard.)
video where the female volcanologist (Tina Neil) and the host (Stephanie)
get out of the helicopter and approach the lava flow.
when they have finished collecting lava samples. Ask: Where are these collections
taking place? (Hawaii or Mauna Loa) Why do you think it's possible to walk
so close to an active volcanic eruption? (It isn't very dangerous, it's
not too hot.) Do you think this is a very explosive type of volcanic eruption?
What evidence do you see that would help you estimate the temperature of
the lava sample? (Possible responses: It started the wooden handle of the
hammer burning, it was too hot for the scientist, it didn't melt the coffee
can, it turned black and solid very fast, it caused the water to turn to
Ask: At what temperature does steel melt or wood burn or water vaporize?
How could we find out? (1000 to 2000 degrees F., 500 degrees F., 212 degrees
F.) List these from coolest to hottest. Ask: Is the lava hotter than 212
degrees? (Yes) 500 degrees? (Yes) 1000 degrees? (Not sure, not enough time.)
Does this lava appear to be life-threatening to the people in the video?
(No) Why or why not? (Too cool, too slow.) List clues you saw that helped
you answer the questions you were asked before the start of the video. (The
questions listed on the chalkboard.)
to Scene 4.
where they are flying over the crater of Mt. St. Helens.
at the section where they are standing in the crater. Explain to the students:
Look for clues that will allow you to estimate the height of the mountain
that was removed in the May 8, 1980 eruption. After listing the clues, make
an estimation. (Several thousand feet.) We are now going to watch a series
of photos taken of the actual eruption. Watch what direction the cloud moves
and what happens to the size of the cloud.
to show the eruption. (Rewind and Play video as many times as you need to
make sure the class has noticed the details of the eruption.)
Ask: What did you see? If you were looking at about 4000 feet of the volcanic
cone, can you estimate the size of the cloud that was ejected? (Several
thousand feet high and several miles long.)
Ask the students: What type of eruption do you think would be
more like the type that destroyed St. Pierre -- the Hawaiian or the Washington
type? (Washington type) Why? (The eruption was sudden and produced a hot
cloud of steam and ash.)
Say: Re-form into your learning groups of three students each. Each group
will now perform a brief experiment to help members understand the effects
of gas pressure on the explosiveness of an eruption.
Say: Take a small balloon and a potato chip bag. Blow them up as much as
you can without breaking them. Hold them underwater and stick a pin into
them. Which one disturbed the water the most? Which one required you to
blow the hardest to blow it up? Which one contained the most gas pressure?
You conclusion is that the (more) the gas pressure, the more powerful the
resulting explosion. (Let students fill in the blank.)
To assess the students' understanding of volcanoes, ask them to do the following:
·Compose a paragraph that describes five differences between the Hawaiian
type and the Washington type of volcanic eruptions.
·List three ways a pyroclastic eruption can destroy people/property.
·Write a set of directions for someone who wants to collect lava from
a Hawaiian volcano.
·Write a newspaper headline that describes the results of a court case
for all the members of the Select Committee that issued the safety report
the day before the Mt. Pelee eruption.
Let students contact students in Martinique and Hawaii (the Big Island)
via US mail, telephone or the Internet to ask them to describe how they
feel about living on a volcanic island.
Require each student to research other events in the history of famous pyroclastic
eruptions. Library resources, the CD-ROM encyclopedia, computer on-line
services and the Internet are required sources for gathering this information.
Students will be required to contact the United States Geological Survey
(USGS) in Arlington, VA and/or geology departments of colleges and universities
to find out what is required to get a degree in geology and to become a
field volcanologist for the USGS.
Students will be asked to interview local residents to record their thoughts
on the Election Day Flood of November 5, 1985. Were the effects of the flood
due to natural causes? Copies of newspaper accounts of the flood and resulting
litigation can be reviewed.
Ask the students to research other natural disaster in their area to determine
if they were made worse by the actions or inactions of public and private
officials. Examine any published or recorded public statements related to
Write a poem that might have been written by the first person to reach St.
Pierre after the eruption.
Draw a storyboard or write a script treatment for a movie about famous pyroclastic
Make a drawing or painting of the eruption of Mt. St. Helens.
Compose a song, skit or video that documents past natural disasters.
Make a report or presentation concerning historical government or private
reporting of pyroclastic eruptions to the public.
Students could practice estimation skills by estimating the temperature
of the room each day, the passage of time during a class, the size of the
room, the length of the hall, and the weight of specific objects in the
room. After they have accomplished this activity, ask them to do actual
measurements to determine their skill at estimation.
Master Teacher: Kenneth J. Harasty
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worksheet associated with this lesson.
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