Volcanoes Flashcards

Questions and Answers

Where are most of Earth's volcanoes found?

Volcanic belts form along the boundaries of Earth's plates.

How do hot spot volcanoes form?

A volcano forms above a hot spot when magma erupts through the crust and reaches the surface.

What is a volcano?

A weak spot in the crust where molten material or magma comes to the surface.

Where are most volcanoes located?

Many of Earth's volcanoes are located along the boundaries of tectonic plates, particularly in the Ring of Fire. Signup and view all the answers

What is a hot spot?

An area where material from deep within the mantle rises and melts, forming magma. Signup and view all the answers

What features form as an oceanic plate moves across a hot spot?

They gradually form a series of volcanic mountains. Signup and view all the answers

Why is it helpful to know the physical and chemical properties of a substance?

These properties can be used to identify a substance or predict how it will behave. Signup and view all the answers

What causes some liquids to flow more easily than others?

Liquids differ in viscosity. Signup and view all the answers

What factors determine the viscosity of magma?

The viscosity of magma depends upon its silica content and temperature. Signup and view all the answers

How hot are magma and lava?

Lava goes from 700-1200 degrees C; magma retains heat for thousands to millions of years. Signup and view all the answers

What is a physical property?

Any characteristic of a substance that can be observed or measured without changing its composition. Signup and view all the answers

What is a chemical property?

Any property that produces a change in the composition of matter. Signup and view all the answers

Is the boiling point of a substance a physical property or a chemical property?

Physical Property Signup and view all the answers

Which of these characteristics are physical properties of magma?

Liquid mixture Signup and view all the answers

What is viscosity?

The resistance of a liquid to flow. Signup and view all the answers

Which has a higher viscosity, a fast-flowing liquid or a slow-flowing liquid?

A slow-flowing liquid. Signup and view all the answers

What can you infer about the amount of friction among the particles of a liquid that has low viscosity?

There is not a lot of friction at all. Signup and view all the answers

What two main factors affect magma's viscosity?

<ol> <li>Silica content, 2) Temperature.</li> </ol> Signup and view all the answers

How does a lava flow cool as it moves away from the vent?

It slows because it's going to become rock as it hardens. Signup and view all the answers

Which type of lava has lower viscosity?

Pahoehoe Signup and view all the answers

What happens when a volcano erupts?

The force of the expanding gases pushes magma from the magma chamber through the pipe until it flows or explodes out of the vent. Signup and view all the answers

What are the two types of volcanic eruptions?

Geologists classify volcanic eruptions as quiet or explosive. Signup and view all the answers

What are a volcano's stages of activity?

Active, dormant, or extinct. Signup and view all the answers

What is Pele's hair?

A type of rock formed from lava, with strands as fine as spun glass. Signup and view all the answers

What does lava begin as?

Lava begins as magma. Signup and view all the answers

What happens to the pressure in magma as it rises toward the surface?

The force of the expanding gases pushes magma from the magma chamber through the pipe until it flows or explodes out of the vent. Signup and view all the answers

How does a volcano form?

A volcano forms where magma breaks through Earth's crust and lava flows out. Signup and view all the answers

Study Notes

Volcanoes Overview

Most volcanoes are located along tectonic plate boundaries.
The Ring of Fire is a significant volcanic belt surrounding the Pacific Ocean.

Volcano Formation

Hot spot volcanoes form when magma penetrates the Earth's crust, erupting to the surface.
A volcano is defined as a weak spot in the crust that allows molten material, or magma, to emerge.

Characteristics of Hot Spots

A hot spot is an area where magma rises from deep within the mantle.
Moving oceanic plates across hot spots can create a chain of volcanic mountains.

Physical and Chemical Properties

Each substance has unique physical and chemical properties, aiding in identification and behavior prediction.
Physical properties can be observed without altering the substance, while chemical properties result in a change in composition.

Viscosity of Magma

Viscosity refers to a liquid's resistance to flow; it varies among different liquids.
Magma's viscosity is influenced by silica content and temperature.
Higher silica content and lower temperatures increase magma's viscosity.

Temperature of Magma and Lava

Lava temperatures range from 700°C to 1200°C; it can retain heat for long periods.
Magma can retain heat for thousands to millions of years.

Types of Lava

Pahoehoe lava has lower viscosity, flows easily, and forms a smooth, rippled surface.
Aa lava has higher viscosity, hardens into rough chunks.

Eruption Dynamics

During an eruption, expanding gases propel magma from the magma chamber through the pipe, leading to flow or explosive outbursts.
Eruptions can be classified as quiet or explosive based on geologists' observations.

Stages of Volcanic Activity

Vulcanologists categorize volcanoes as active, dormant, or extinct based on their activity levels.

Unique Volcanic Features

"Pele's hair" is a glass-like rock formed from lava, consisting of fine, spun strands.

Other Characteristics

As magma rises toward the surface, pressure builds up; the eruption occurs due to the gas expansion.
A volcano forms when magma breaks through the Earth's crust and is released as lava.

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Description

Test your knowledge of volcanoes with these flashcards. This quiz covers the formation, location, and definitions related to volcanic activity on Earth. Perfect for students studying geology or earth sciences.