Class V: SCIENCE [Ch-9 Volcanoes, Earthquakes and Storms]

Define the terms

1. Natural disasters- Extreme sudden events caused by environmental factors that injure people or damage people.

2. Volcano- Crack in earth's crust through which hot liquid lava comes out along with ash and gases.

3. Active Volcanoes- Volcanoes that can erupt at any time or have erupted in the recent past.

4. Dormant Volcanoes- Volcanoes that have not erupted in recent years but may erupt in the future.

5. Extinct Volcanoes- Volcanoes that have stopped erupting and have no chance of their eruption.

Answer in one line 

1. What is an earthquake?

Ans. The sudden shaking of an earth's surface is known as an earthquake.

2. What is Seismograph?

Ans. An instrument to measure the intensity of the earthquake is called a seismograph.

3. Who build the first seismograph?

Ans. The first seismograph was built by the Chinese philosopher Chang Heng in 132 AD.

4. What is the cause of most natural disasters?

Ans. Most natural disasters are caused by weather.

5. Name the rocks formed by the cooling of lava?

Ans. Igneous rocks are formed by the cooling of lava.

Answer in short

1. Name a few areas affected by the tsunami in 2004.

Ans. Sri Lanka, India, Thailand, Maldives, and Somalia were the areas affected by the tsunami in 2004.

Answer in detail

1. How does a volcano erupt? How is lava different from magma?

i) A volcano is a crack in the earth's surface.

ii) It is usually in the form of a conical mountain.

iii) There is a vertical tunnel in the mountain through which the lava comes out. (Very hot liquid rock called lava)

iv) When the lava is underground, it is called magma.

2. What is an epicenter? How does an earthquake occur?

i) The place where the earthquake originates is called the epicenter.

ii) The earth's surface is made up of plates (Which may be big or small) called tectonic plates.

iii) There is smooth movement between the plates but at times the movement is sudden and severe.

iv) These shockwaves give rise to earthquakes.

3. How do you measure an earthquake? Also, mention the damage which is caused by an earthquake.

i) Scientists measure earthquakes with an instrument called a seismograph using Richter Scale.

ii) The weakest earthquakes are close to 1 and the severe ones are close to 9 on Richter Scale.

Damage caused due to earthquakes-

iii) Many people lose their lives as they get trapped under collapsed buildings.

iv) The roads and the bridges get damaged due to the earthquakes.

4. What are tidal waves? How does a tsunami occur?

i) Earthquake or Volcanic eruption can take place under sea also and is called a tsunami.

ii) During a tsunami the waves move at a great speed.

iii) It causes massive destruction on the sea shore.

iv) The rise and fall of sea waves are called tidal waves.

Give Reason

1. Why should fishermen not go near the seashore when there is high tide?

Ans. During high tide, the waves become very dangerous because of gravity. Due to these, there is a danger of being lost and sinking in the sea as tides pull inside the sea. Hence fishermen should not go near the seashore when there is high tide.

2. Name the calamity which struck Sumatra in Indonesia on August 4, 2015?

Ans. The calamity that struck Sumatra in Indonesia on August 4, 2015, was an earthquake.

Story Based Question

Sanskar is alone at home. He feels the ground shaking and sees the fans swinging.

1. What do you think has happened?

Ans. She is experiencing an earthquake.

2. What should Sanskar do?

Ans. Sanskar should take cover under a desk or table.

Chapter Completed