Metallurgy

Along with the societal and metaphorical exploration of value during the Coin Arc, the upper elementary and middle school students explored the science of the physical stuff that coins are made of: metal.

Students focused on the types of metals, their uses, and the properties that metals have in common, such as high electrical and thermal conductivity, ductility and luster. The question, “What are metals?”’ led to the students wondering, “How do different metals change?” They explored the reactiveness of many commonly used metals to oxidation, and they set to oxidizing pennies with common household products, which led to explorations of kitchen chemistry.

The students practiced asking meaningful questions and conducted a careful investigation by testing to see what household chemical and application process would yield the greatest amount of bright blue copper oxidation.

As the students waited to observe their oxidation reactions, they learned about the chemistry of oxidation, and the difference between physical and chemical change. They explored the role of metal oxidation in biological systems, namely how animals utilize metals such as iron, copper, and vanadium to carry oxygen throughout their bodies. Their biological exploration of oxidation wrapped-up with a closer look at research surrounding the copper containing electric blue blood of horseshoe crabs.

The students continued their explorations of chemical and physical processes by turning pennies silver and gold color with plating and metallurgy. The students used a sodium hydroxide solution to plate elemental zinc onto copper pennies to give them a silvery color, and then melted zinc and copper together to create the alloy brass, making a golden color. In doing so the students gained experience using a scientific procedure to achieve desired results. After the introductory lab, the students explored common alloys such as bronze, steel, and brass, and they learned about their history, make-up, production and use.

During Coin, the students were also introduced to scientific notetaking. As the year progresses, their notebooks will encourage them to reflect on inquiry-based observations, activities, investigations, and experiments, and be used as a catalyst for communicating their understanding of science concepts.