Where Do Metals Come From?
Computers. Smartphones. Jewelry. Skyscrapers. Automobiles. Look around you! Everywhere, you’ll see objects that couldn’t exist without metal. Can you imagine life without this strong, shiny substance?
Even the human body needs metal! It uses cobalt to make red blood cells. Zinc helps the immune system. High levels of mercury and copper can cause major problems. Even your bones need help from one type of metal—calcium!
Yes, metals are very important. They help keep people healthy. People also use metals to build objects that change the world. But where do all those metals come from?
Some metals are found in the Earth’s crust. Cobalt, iron, and nickel are common in nature. So are gold, zinc, tin, copper, and many others. However, it’s uncommon to find many metals in large quantities separate from other materials. More often, metals found in nature are mixed with rocks and minerals.
When metal is mixed into rocks and minerals, it’s called ore. Before using metals, people have to remove them from the ore. This process is called smelting. It involves heating the metal past its melting point. Once melted, the metal can be filtered to remove other materials.
Metals found in nature are brittle. They’re also prone to rust and corrosion. To make stronger, longer-lasting materials, people mix metals together and with other substances. The result is called a metal alloy.
Do you know of any metal alloys? One of the most common metal alloys is steel. It’s made by combining iron and carbon. Stainless steel is an alloy often used to make eating utensils. It’s a mixture of iron, carbon, chromium, and molybdenum.
Have you ever seen a piece of jewelry made of rose gold? That’s an alloy made of gold and copper. How about a cast-iron skillet? Cast iron is another alloy. It’s a mixture of iron and carbon. Another common alloy is bronze, made from copper and tin.
What items do you use every day that might contain metals? How about metal alloys? Do you ride to school in a bus or other vehicle? It’s likely made of steel. The chairs in your classroom may contain iron, aluminum, or stainless steel. If you use any digital technology, it likely contains gold, silver, copper, or platinum. Once you start noticing all the metal around you, it’s hard to stop!
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