Volcanoes Worksheets - 15 Worksheets Library - Free Printable
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Step-by-step solution for: Volcanoes Worksheets - 15 Worksheets Library
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Show Answer Key & Explanations
Step-by-step solution for: Volcanoes Worksheets - 15 Worksheets Library
Since the image you mentioned contains a worksheet titled "Volcanic Eruptions" with several questions, I’ll solve and explain each question based on general scientific knowledge. Here's a complete response to all the questions:
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Answer: Volcanoes erupt when pressure builds up beneath the Earth’s surface due to the accumulation of magma (molten rock) in a magma chamber. This pressure increases until it overcomes the strength of the surrounding rock, causing the magma to force its way through cracks and fissures to the surface.
Explanation: Eruptions typically occur at tectonic plate boundaries (like convergent or divergent boundaries) or over hotspots. The buildup of gases dissolved in magma also contributes to the pressure, making eruptions more explosive.
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Answer: Volcanic eruptions can occur very quickly—sometimes in seconds or minutes—and can last from a few hours to several years, depending on the type of volcano and eruption style.
Explanation: Some eruptions are sudden and explosive (e.g., Mount St. Helens in 1980), while others are slow and effusive (e.g., Hawaiian lava flows). The speed depends on factors like magma viscosity, gas content, and pressure buildup.
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Answer: False
Explanation: Volcanic eruptions vary widely. They can be:
- Effusive: Lava flows out slowly (common in shield volcanoes).
- Explosive: Violent eruptions with ash, pyroclastic flows, and debris (common in stratovolcanoes).
The type of eruption depends on magma composition (silica content), gas content, and tectonic setting.
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Answer:
The outermost layer of the Earth is called the crust. It is composed of the continental crust and the oceanic crust.
Explanation:
- The crust is the thin, solid outer layer.
- The continental crust is thicker and less dense, found under land.
- The oceanic crust is thinner and denser, found under oceans.
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Answer: The core (specifically the outer and inner core)
Explanation:
- The outer core is liquid iron and nickel and has temperatures ranging from about 4,000°C to 6,000°C.
- The inner core is solid due to extreme pressure and reaches temperatures up to 7,000°C.
- These high temperatures come from residual heat from Earth’s formation and radioactive decay.
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Answer: When rock gets extremely hot, it begins to melt and turns into magma.
Explanation:
- At high temperatures and pressures deep within the Earth, rocks undergo metamorphism or melt.
- Magma forms when rocks reach their melting point, often due to rising temperature, decreasing pressure, or addition of water (which lowers melting point).
- This molten rock can then rise toward the surface, potentially leading to volcanic eruptions.
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Answer:
A volcano erupts when magma rises from deep within the Earth and reaches the surface. Here’s how it happens:
1. Magma Formation: Heat and pressure in the mantle cause rocks to melt, forming magma.
2. Rising Magma: Magma is less dense than surrounding rock, so it rises through cracks and weaknesses in the crust.
3. Pressure Buildup: As magma rises, dissolved gases (like water vapor and carbon dioxide) expand, increasing pressure.
4. Eruption: When pressure becomes too great, the magma breaks through the surface, causing an eruption.
5. Release of Materials: Lava, ash, gases, and volcanic rocks are expelled into the air and onto the ground.
6. Types of Eruptions: Depending on magma composition, eruptions can be gentle (lava flows) or violent (explosive with ash clouds and pyroclastic flows).
Example: A quiet eruption occurs at Hawaii’s Kīlauea, while a violent one occurred at Mount Vesuvius in 79 AD.
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✔ Summary of Answers:
| Question | Answer |
|--------|--------|
| 1 | When pressure from magma and gases builds up enough to break through the Earth’s crust. |
| 2 | Eruptions can happen rapidly (seconds/minutes) or last for years; speed varies by volcano. |
| 3 | False – eruptions differ in style and intensity. |
| 4 | Crust; continental crust and oceanic crust. |
| 5 | The core (especially outer and inner core). |
| 6 | Rock melts into magma. |
| 7 | Magma rises, pressure builds, and materials erupt through vents. |
Let me know if you'd like this formatted as a printable answer key!
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1. When do volcanoes erupt?
Answer: Volcanoes erupt when pressure builds up beneath the Earth’s surface due to the accumulation of magma (molten rock) in a magma chamber. This pressure increases until it overcomes the strength of the surrounding rock, causing the magma to force its way through cracks and fissures to the surface.
Explanation: Eruptions typically occur at tectonic plate boundaries (like convergent or divergent boundaries) or over hotspots. The buildup of gases dissolved in magma also contributes to the pressure, making eruptions more explosive.
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2. How fast do volcanic eruptions occur?
Answer: Volcanic eruptions can occur very quickly—sometimes in seconds or minutes—and can last from a few hours to several years, depending on the type of volcano and eruption style.
Explanation: Some eruptions are sudden and explosive (e.g., Mount St. Helens in 1980), while others are slow and effusive (e.g., Hawaiian lava flows). The speed depends on factors like magma viscosity, gas content, and pressure buildup.
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3. True or false: All volcanic eruptions occur in basically the same way.
Answer: False
Explanation: Volcanic eruptions vary widely. They can be:
- Effusive: Lava flows out slowly (common in shield volcanoes).
- Explosive: Violent eruptions with ash, pyroclastic flows, and debris (common in stratovolcanoes).
The type of eruption depends on magma composition (silica content), gas content, and tectonic setting.
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4. The outermost layer of the Earth is called the ____________. It is composed of the ____________ and the ____________.
Answer:
The outermost layer of the Earth is called the crust. It is composed of the continental crust and the oceanic crust.
Explanation:
- The crust is the thin, solid outer layer.
- The continental crust is thicker and less dense, found under land.
- The oceanic crust is thinner and denser, found under oceans.
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5. In which layer of the Earth do temperatures get extremely hot?
Answer: The core (specifically the outer and inner core)
Explanation:
- The outer core is liquid iron and nickel and has temperatures ranging from about 4,000°C to 6,000°C.
- The inner core is solid due to extreme pressure and reaches temperatures up to 7,000°C.
- These high temperatures come from residual heat from Earth’s formation and radioactive decay.
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6. What happens to rock when it gets extremely hot?
Answer: When rock gets extremely hot, it begins to melt and turns into magma.
Explanation:
- At high temperatures and pressures deep within the Earth, rocks undergo metamorphism or melt.
- Magma forms when rocks reach their melting point, often due to rising temperature, decreasing pressure, or addition of water (which lowers melting point).
- This molten rock can then rise toward the surface, potentially leading to volcanic eruptions.
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7. Explain how a volcano erupts.
Answer:
A volcano erupts when magma rises from deep within the Earth and reaches the surface. Here’s how it happens:
1. Magma Formation: Heat and pressure in the mantle cause rocks to melt, forming magma.
2. Rising Magma: Magma is less dense than surrounding rock, so it rises through cracks and weaknesses in the crust.
3. Pressure Buildup: As magma rises, dissolved gases (like water vapor and carbon dioxide) expand, increasing pressure.
4. Eruption: When pressure becomes too great, the magma breaks through the surface, causing an eruption.
5. Release of Materials: Lava, ash, gases, and volcanic rocks are expelled into the air and onto the ground.
6. Types of Eruptions: Depending on magma composition, eruptions can be gentle (lava flows) or violent (explosive with ash clouds and pyroclastic flows).
Example: A quiet eruption occurs at Hawaii’s Kīlauea, while a violent one occurred at Mount Vesuvius in 79 AD.
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✔ Summary of Answers:
| Question | Answer |
|--------|--------|
| 1 | When pressure from magma and gases builds up enough to break through the Earth’s crust. |
| 2 | Eruptions can happen rapidly (seconds/minutes) or last for years; speed varies by volcano. |
| 3 | False – eruptions differ in style and intensity. |
| 4 | Crust; continental crust and oceanic crust. |
| 5 | The core (especially outer and inner core). |
| 6 | Rock melts into magma. |
| 7 | Magma rises, pressure builds, and materials erupt through vents. |
Let me know if you'd like this formatted as a printable answer key!
Parent Tip: Review the logic above to help your child master the concept of worksheet on volcanoes.
