W: Hello, students. Perhaps no material on earth has been more important in human history than metal. Today, we’re going to discuss the contribution of metals to the development of civilization. First, gold was considered the most valuable metal due to its beauty and scarcity. Because of its visual appeal and ability to be easily shaped, it’s been used to decorate religious places and objects. Second, silver was mainly prized for being the shiniest of all metals. It’s been one of the main forms of currency since it was the chief metal used for making coins. Next, iron became widely used once humans discovered techniques to strengthen it. This metal was fashioned into tools that revolutionized farming, and later, machines that industrialized the world. Finally, aluminum is the most abundant metal in the world and is also lightweight. That’s why it’s been essential to countless industries in modern society from automotive to aerospace to household products. Now, let’s watch a short related video.