Student’s activity.
Ex: Earthquakes:
The earth’s surface is formed of massive slabs of rock called plates. These are called tectonic plates, are always moving. Sometimes they just slide past one another. At another time they actually collide with one another. Plate movements cause the build up of tremendous quantities of energy in the rock. When the energy is released, it produces vibrations that travel through the rock, leading to earthquakes. During earthquakes, faults, or giant cracks, are produced by the pressure of moving rocks.
Volcanoes:
Deep within the earth it is so hot that some rocks slowly melt and become a thick flowing substance called magma. Because it is lighter than the solid rock around it, magma rises and collects in magma chambers. Eventually some of the magma pushes through vents and fissures in the earth’s surface. Then a volcanic eruption occurs.
Their effect on human life :
1. Major earthquakes and volcano eruption can affect human life.
2. Roads can be damaged and delivery of food can be disrupted.
3. Clean, drinking water may not be available.
4. Sewer system may leave, causing diseases.
5. Gas line could leak, causing health issue.
6. All the surroundings can get covered with ash.
7. Communication system fails.
8. They destroy property and threaten human lives.
