Volcanoes — Earth science, 4–6 years
How hot material from inside Earth can reach the surface through a volcano. Earth science, 4–6 years.
What a volcano is
A volcano is an opening in Earth’s crust where hot melted rock, gas or ash can come out. Melted rock below the ground is called magma; when it reaches the surface, it is called lava. Some volcanoes are tall mountains, but others are low cracks or openings.
Why volcanoes erupt
People needed to explain why some mountains suddenly sent out smoke, ash and fire. Deep inside Earth, heat can melt rock, and gases can make pressure in the melted material. If pressure finds a path through the crust, magma rises and may erupt. Not every volcano erupts often, and many are quiet for a long time.
A safe model eruption
Use an adult-approved model with a cup, bicarbonate of soda, vinegar and food colouring, never a real volcano. Step 1: put two spoonfuls of bicarbonate in the cup. Step 2: add coloured vinegar. Step 3: bubbles form and foam rises because the reaction makes gas. This models rising foam, not hot lava or every part of a real eruption.
A mountain is not always a volcano
It is reasonable to call every cone-shaped mountain a volcano, because many famous volcanoes have that shape. But a mountain can form when Earth’s crust is pushed up, while a volcano needs an opening and volcanic material. A volcano can also be hidden, low or under the sea, so its shape alone is not enough.
Volcanoes in real life
Volcanic ash can make air unsafe, and lava can damage homes, roads and fields, so people near volcanoes use warnings and evacuation plans. Volcanic rock can later form new land, and ash can add minerals to soil. Never approach smoke, ash or lava; follow local safety instructions and stay with a trusted adult.
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