Geology Lesson for Kids: What Happens Inside a Volcano?
Volcanic eruptions are a rare yet fascinating natural phenomenon. There are, on average, 35 volcanic eruptions every year. Many kids know about volcanoes in general, but how they work is often an intriguing mystery. What happens inside the earth when a volcano erupts?
Looking inside the earth’s layers can uncover this and spark a sense of wonder in your student. To create your own volcano in the comfort of your home, explore the instructographic below for a safe, fun (and slightly messy) activity.
Inside the Earth’s Crust
Understanding volcanoes starts with understanding the structure of the earth. The outer part of the earth that we see, called the crust, is the top layer of many layers. Underneath the crust are bigger and hotter layers that lead to the center of the earth, the core. Within these layers are huge sections called tectonic plates, which we explain in more detail below. At the bottom of the crust, before we get to the deeper layers, is where we find hot liquid rock called magma, which might be beneath massive amounts pressure.
Tectonic Plates, Magma, Friction, and Pressure
Tectonic plates are parts of the crust that act like giant puzzle pieces. The plates have the ability to move, and when they do, they create problems—like earthquakes, tsunamis, and volcanoes. These natural disasters happen because the movement of the plates cause friction. That friction can create pressure on the magma, and the magma can no longer stay in one place. The magma starts moving. Volcanoes occur when the pressure causes the magma to move toward the surface to flow out or erupt.
Magma or Lava?
While molten rock remains inside the volcano, and inside the earth’s crust, it is called magma. When the magma comes to the surface and erupts or flows out of the volcano, the term for it is lava.
The Idea of Plate Tectonics
Tectonic plates have been linked to the continents’ movements. When the plates move apart or hit one another, earthquakes are created, and they cause the land to break, collide, and move. Plate tectonics is the reason for the formation of continents we know today. When the plates move apart, volcanoes can form and erupt, and when plates move or collide, earthquakes can occur. Plates coming together can also form mountains over time.
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Three Volcanic Stages
There are three stages of a volcano: active, dormant, and extinct.
- Active—A volcano is active if it is erupting, or may erupt soon.
- Dormant—A dormant volcano may have erupted before, but it is no longer erupting. However, it has the ability to erupt again.
- Extinct—An extinct volcano is not erupting and will never erupt again.
Volcanoes Around the World
There is not an exact number of volcanoes recorded because they are difficult to count. They can be found in the ocean and on land, and the same source of magma can erupt in multiple spots on the earth’s surface.
A majority of volcanoes are located on the sides of the continents that border the Pacific Ocean. The continents form a U shape, which is known as the Ring of Fire. Around the ring, eruptions and earthquakes are common.
Volcanoes in the ocean work the same way land volcanoes do. Eighty percent of Earth’s volcanic eruptions happen under the water’s surface. Searching for volcanoes in the ocean can be difficult because they may be in deep waters where they’re not easily seen. Dormant and extinct volcanoes would also be challenging to identify because the magma isn’t being pushed up and out of the water.
Earth’s Biggest Volcano
The biggest volcano known is Mauna Loa, which is one of five volcanoes located on Hawaii’s islands. It is measured at 13,678 feet tall. Some scientists believe Mauna Loa will erupt again, because there is past evidence that the volcano erupted every six years. However, the volcano hasn’t erupted since 1984, and there is no definitive way of knowing when it will erupt again.
Has your child asked about volcanoes? Have you tried any science experiments to show a volcano erupting? We’d love to hear. Share with us and other parents in the comments below.