Did you know that the Earth we live on has been constantly changing for millions of years? You see, the shapes of the land, mountains, and even the ocean floor haven't always been as they are now. So, the movement of Earth's plates has slowly but surely formed beautiful and amazing natural features. This is what is studied in branches of geology, the science that explains how the Earth changes over time. And the natural beauty we see, such as mountains, valleys, and islands, is the result of a long process called landscape morphology. You surely still remember when you studied the branches of science in the 7th grade. One of them is geology, which discusses the Earth and all its changes. Now, did you know that most of the beautiful scenery we see, like mountains, beaches, and valleys, is the result of natural processes that have taken place over millions of years? These shapes on the Earth's surface are called landscape morphology. Let's observe some examples of landscapes found in Indonesia. A landscape is a feature of the Earth's surface formed naturally, such as mountains, rivers, beaches, and valleys. The formation process can be caused by the movement of tectonic plates, erosion, or volcanic activity, such as weathering and others. As an archipelago, Indonesia has very diverse and beautiful landscapes. Starting from the Jayawijaya mountains in Papua and Lake Toba in Sumatra, to the rows of exotic beaches in Bali and Lombok. Because this diversity of landscapes is one of our natural treasures that we should protect and be proud of. Landscape changes occur due to geological forces, which are the powers that shape the Earth's surface, divided into two. First, there is exogenous from outside the Earth, and endogenous, from inside the Earth. In this chapter, we will explore how forces from within the Earth, such as tectonism and volcanism, shape the Earth's structure and create extraordinary natural wonders. There are three characteristic layers that make up the Earth. First, there is the Earth's crust, then the Earth's mantle, and finally the outer and inner core. Have you ever seen a boiled egg? It turns out that the Earth's structure is similar to a boiled egg. Wait, how can that be? Well, the eggshell represents the Earth's crust, which is the thin outer part. Then the egg white represents the Earth's mantle. The second part, which is somewhat thick, and the egg yolk represents the Earth's core. Each layer has unique characteristics that compose and shape the Earth, the place where we live. Do you know that the outermost part of the Earth where we stand is called the Earth's crust? Although it is the thinnest layer, the Earth's crust stores many important elements and valuable minerals. This crust is also where all life takes place, both on land and on the ocean floor. Let's get to know the characteristics of this layer of the Earth more deeply. Next, beneath the Earth's crust we walk on lies a thick layer called the mantle. This layer is the thickest and heaviest, extending thousands of kilometers deep. Although composed of solid rock, intense heat makes it plastic and capable of movement. This movement influences Earth's activity, such as earthquakes and volcanoes. There are two parts to Earth's core: the inner core and the outer core. Have you ever imagined the Earth's innermost, boiling-hot liquid center? That is where the outer core lies—a unique layer, distinct from the crust and mantle, as it consists of dense liquid. It is not water, but hot metals like iron and nickel that are constantly moving within it. The movement of this liquid even plays a key role in creating the Earth's magnetic field, which protects life on the surface. Imagine being at the Earth's center, where temperatures reach an incredible 7,000 degrees Celsius and pressure is so immense that even liquid metal turns solid. This is the Earth's inner core. The innermost layer, composed of solid iron, nickel, and other elements like sulfur and carbon. Although hotter than the Sun's surface, extreme pressure keeps it solid, making this layer the center of Earth's strength and stability. The large, moving sections are known as tectonic plates. These plates are like giant puzzle pieces that continuously drift very slowly over the Earth's mantle. This movement causes the formation of mountains, earthquakes, and even continents shifting position over millions of years. Understanding tectonic plates helps us realize how the Earth constantly changes over time. Let's take a look. The Earth's plates beneath us are always moving. This movement is called tectonism, which refers to the movement of Earth's plates. This is different from volcanism, which relates to volcanic activity. So, tectonism is part of endogenic force, which is power originating from inside the Earth. Now, let's look at the continents of the world. This is a result caused by tectonism, where the movement of Earth's plates has fractured the various continents. Furthermore, tectonism involves horizontal and vertical movements that cause changes to the Earth's surface. These movements are called tectonic movements, which shape the Earth's surface by creating cracks, folds, depressions, and faults. There are three types of plate movements. First, divergent movement, where they move away from each other. A divergent plate boundary occurs when two tectonic plates move apart. As a result, magma from inside the Earth rises to the surface and forms a new layer of crust. An example is the formation of the Mid-Atlantic Ridge, a mountain range on the floor of the Atlantic Ocean. The second is the convergent plate boundary, where they collide. So, this convergent plate boundary occurs when two plates collide, causing one plate to slide beneath another. This movement can cause very powerful earthquakes, such as the earthquake and tsunami in Aceh on December 26, 2004. The third one is the transform plate boundary. or passing each other by. Transform movement occurs when two plates grind against each other horizontally in opposite directions. This friction generates energy that can trigger shallow earthquakes. An example is the San Andreas Fault in California, United States, which is 1300 km long. Have you ever felt the ground shake suddenly? That is what is called an earthquake. An earthquake is a natural event that can happen anytime and anywhere. Especially in regions like Indonesia, which lies along the Ring of Fire. Now, in this 8 th-grade science lesson, we will learn how earthquakes occur, what causes them, and their impact on life. What is a seisme? Seisme is a vibration that occurs due to the release of energy from within the Earth. This vibration arises because of accumulated energy between continental and oceanic plates. If the energy is great, an earthquake will occur. So, seisme is the scientific term for vibration. While an earthquake is the event that we experience. Types of earthquakes based on how they occur. Well, they are divided into three. There are tectonic earthquakes, volcanic earthquakes, and collapse earthquakes. They can be seen as follows. Earthquake strength can be measured using an instrument called a seismograph, and the unit of strength is called the Richter scale. Now, you can check the earthquake strength or magnitude measured by the Richter scale. Let's take a look. Earthquake categories based on their magnitude. If it's 3 to 3.9, that means minor. Now, if it's even more than 8, it means great. This can be determined by the Richter scale found in the following table. Volcanoes often sound scary because of their massive eruptions. However, did you know that volcanoes also bring many benefits to life? In this 8 th-grade science lesson, you will learn about volcanoes. How they are formed and their impacts on daily life. The occurrence of volcanoes based on Earth's plates. Well, they are formed as a result of tectonic plate movements that shape the Earth's crust, through three processes. First is the subduction zone or plate collision; second is divergent, which is the spreading of plates. Then the third one is from a hotspot, where magma rises from a hot spot in the Earth's mantle and forms a volcano in the middle of a plate. Next are the benefits of volcanoes, which can be seen as follows. Thank you in advance. Don't forget to follow, subscribe, and bye-bye.