Short & Long Questions: The Interior of the Earth | Window on the Word Class 7: Solutions, Notes & Worksheets PDF Download

Short Answer Questions

Q1: What are the three main layers of the Earth?
Ans: The three main layers of the Earth are the crust, mantle, and core.

Q2: What is the composition of the continental crust?
Ans: The continental crust is mainly composed of silica and aluminium, also known as sial.

Q3: What is the difference between oceanic crust and continental crust?
Ans: Oceanic crust is thinner, denser, and mainly composed of silica and magnesium (sima), whereas continental crust is thicker and composed of silica and aluminium (sial).

Q4: What is the main component of the Earth's mantle?
Ans: The mantle is mainly composed of minerals like silica, iron, magnesium, and aluminium.

Q5: What is the temperature range in the upper mantle?
Ans: The temperature in the upper mantle varies between 650 and 1200°C.

Q6: What are the two minerals that make up the Earth's core?
Ans: The Earth's core is mainly made up of nickel and iron (nife).

Q7: How are igneous rocks formed?
Ans: Igneous rocks are formed when magma rises to the surface, cools down, and solidifies.

Q8: What distinguishes extrusive igneous rocks from intrusive igneous rocks?
Ans: Extrusive igneous rocks form from quickly cooled lava on the Earth's surface, resulting in fine-grained textures, while intrusive igneous rocks form from slowly cooled magma beneath the surface, resulting in coarse textures.

Q9: What are sedimentary rocks primarily formed from?
Ans: Sedimentary rocks are primarily formed from compressed and hardened sediments, which are fragments of other rocks.

Q10: Give an example of a non-metallic mineral found in sedimentary rocks.
Ans: Limestone is an example of a non-metallic mineral found in sedimentary rocks.

Long Answer Questions

Q11: Explain the formation of igneous rocks in detail.
Ans: Igneous rocks are formed from cooled and solidified magma. When magma rises towards the Earth's surface, it cools down and solidifies. This process can occur either on the surface, resulting in extrusive igneous rocks, or beneath the crust, leading to intrusive igneous rocks. Extrusive rocks have fine-grained textures due to rapid cooling, while intrusive rocks have coarse textures due to slow cooling.

Q12: Describe the rock cycle and its significance.
Ans: The rock cycle is a continuous process through which rocks change from one form to another over time. It starts with magma deep inside the Earth, which solidifies to form igneous rocks. These rocks can then erode and weather, becoming sediments. Over time, sediments can compact and harden, forming sedimentary rocks. With increased pressure and temperature, both igneous and sedimentary rocks can transform into metamorphic rocks. This cycle is crucial as it recycles rocks, contributing to the Earth's geological processes.

Q13: Differentiate between metallic and non-metallic minerals, providing examples of each.
Ans: Metallic minerals are naturally occurring substances found in rocks that contain metals. Examples include iron ore, copper, and bauxite. Non-metallic minerals are also naturally occurring substances in rocks, but they do not contain metals. Examples are limestone, mica, and kaolinite.

Q14: Explain how fossil fuels are formed and their importance.
Ans: Fossil fuels are formed from the decomposition of ancient plants and animals that were buried deep within the Earth's crust millions of years ago. Over time, the remains transformed into coal, oil, and natural gas. These fuels are crucial sources of energy for activities like cooking, transportation, and industrial processes.

Q15: Discuss the various uses of rocks, minerals, and fossil fuels.
Ans: Rocks are used in construction, making building materials, cement, concrete, and sculptures. Minerals are sources of important metals like iron, gold, aluminium, copper, and silver. Fossil fuels are essential for energy, used in cooking, transportation, and various industries. Understanding these resources helps us appreciate their significance in our daily lives and the Earth's processes.