Class 8 Science Chapter 12 Important Question Answers - Some Natural Phenomena

Q1: What causes lightning, and how did ancient civilizations interpret it?
Ans: Lightning is caused by the accumulation of charges in clouds. Ancient civilizations thought it was the wrath of gods visiting them due to their lack of understanding.

Q2: Explain the connection between rubbing a plastic scale on dry hair and charging by rubbing.
Ans: Rubbing a plastic scale on dry hair causes it to acquire an electric charge, demonstrating the concept of charging by rubbing.

Q3: Describe the different types of electric charges and their interactions.
Ans: There are two types of charges, positive and negative. Charges of the same kind repel each other, while charges of different kinds attract each other.

Q4: Why is it conventional to call the charge acquired by a glass rod when rubbed with silk as positive?
Ans: It is a convention to call the charge acquired by a glass rod when rubbed with silk as positive for ease of reference and consistency in scientific discussions.

Q5: Explain how an electroscope works and how it detects the presence of charge.
Ans: An electroscope detects the presence of charge by using metal strips that repel each other when charged, indicating the presence of charge on an object.

Q6: What is the process of earthing, and why is it essential in electrical safety?
Ans: Earthing is the process of transferring charge from a charged object to the Earth. It's essential to prevent the buildup of excess charge and ensure safety.

Q7: How is lightning generated during a thunderstorm, and what precautions should one take during lightning?
Ans: Lightning is generated by the accumulation of positive and negative charges in clouds. Precautions during lightning include seeking shelter in buildings or vehicles, avoiding open spaces, and not using umbrellas.

Q8: Explain the purpose and functioning of lightning conductors in protecting buildings from lightning strikes.
Ans: Lightning conductors provide a path for electric charge to safely flow from a building to the ground, preventing lightning damage.

Q9: What is an earthquake, and what causes it? Why is it difficult to predict earthquakes?
Ans: An earthquake is a sudden shaking of the Earth caused by disturbances in the Earth's crust. Predicting earthquakes is challenging because their occurrence and timing are unpredictable.

Q10: How are earthquakes related to the movement of Earth's tectonic plates?
Ans: Earthquakes are related to the movement of tectonic plates. When these plates brush past each other or collide, they can cause disturbances in the Earth's crust, leading to earthquakes.

Q11: What are seismic or fault zones, and why are they more likely to experience earthquakes?
Ans: Seismic or fault zones are weak zones along plate boundaries where earthquakes are more likely to occur due to the movement of tectonic plates.

Q12: How is the power of an earthquake measured, and what is the Richter scale?
Ans: The power of an earthquake is measured using the Richter scale, with destructive earthquakes having magnitudes higher than 7 on this scale.

Q13: What precautions can people take to protect themselves from earthquake damage in seismic zones?
Ans: Precautions in seismic zones include designing buildings to withstand tremors, securing heavy objects, and having fire-fighting equipment available.

Q14: Explain the safety measures individuals should take during an earthquake if they are at home or outdoors.
Ans: During an earthquake, individuals should take shelter under sturdy furniture, stay away from tall objects, and avoid coming out if they are indoors. Outdoors, they should find open spaces away from buildings and trees.

Q15: How can scientists improve our understanding of natural phenomena like lightning and earthquakes, and why is this understanding crucial?
Ans: Scientists continuously research and study these phenomena to improve our understanding and develop better safety measures. Understanding these phenomena is essential to protect lives and property.