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Listen to an Academic Talk Test #074
Listen to an Academic Talk
1. What is the main purpose of the talk?
A) To compare different types of hot springs
B) To describe the geology of Yellowstone National Park
C) To explain the conditions that create geysers
D) To discuss the uses of geothermal energy
2. According to the professor, what prevents the underground water in a geyser system from boiling immediately?
A) The low temperature of the rock
B) The chemical composition of the water
C) The pressure from water above it
D) The lack of a sufficient heat source
3. What can be inferred about areas of the world that do not have geysers?
A) They receive very little rainfall
B) They may lack one of the three required conditions
C) They are located far from any body of water
D) Their underground rock is too soft
4. Why does the professor mention a "plumbing system"?
A) To describe how water gets into the ground
B) To explain a key part of the eruption mechanism
C) To compare a geyser to a man-made structure
D) To suggest that geysers are predictable
Professor: Today we'll look at one of Earth's most spectacular natural phenomena: geysers. A geyser is a hot spring that intermittently erupts, forcefully ejecting a column of water and steam. For a geyser to exist, you need a rare combination of three specific geological conditions.
First, you need an intense source of heat, which is typically magma located not too far below the Earth's surface. Second, you need a consistent and abundant supply of groundwater.
And third, and this is crucial, you need a unique underground plumbing system—a series of fissures and constrictions in the rock. The water seeps down, gets superheated by the magma, but the pressure from the water above and the narrow channels prevents it from boiling.
Eventually, the pressure builds to a critical point, and...boom! It erupts. This specific set of requirements is why geysers are so rare, with about half of the world's active ones located in one place: Yellowstone National Park.
First, you need an intense source of heat, which is typically magma located not too far below the Earth's surface. Second, you need a consistent and abundant supply of groundwater.
And third, and this is crucial, you need a unique underground plumbing system—a series of fissures and constrictions in the rock. The water seeps down, gets superheated by the magma, but the pressure from the water above and the narrow channels prevents it from boiling.
Eventually, the pressure builds to a critical point, and...boom! It erupts. This specific set of requirements is why geysers are so rare, with about half of the world's active ones located in one place: Yellowstone National Park.
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