Creating Silver Nanoparticles
A cluster of silver nanoparticles. Measurements below the image signify the measurement of the particles (μm) is in micrometers.Copyright 2019 Theivasanthi, CC-BY-SA-4.0 Wikimedia Commons, https://commons.wikimedia.org/wiki/File:Impressive_Silver_Nanoparticles.jpg
Students create silver nanoparticles using a chemical process; however, since these particles are not observable to the naked eye, they use empirical evidence and reasoning to discover them. Students first look for evidence of a chemical reaction by mixing various solutions and observing any reactions that may occur. Students discover that copper and tannic acids from tea reduce silver nitrate, which in turn form silver. They complete the reaction, allow the water to evaporate, and observe the silver nanoparticles they created in plastic dishes using a stereo microscope. Students iterate on their initial process and test to see if they can improve the manufacturing process of silver nanoparticles.
Chemical engineers develop processes to manufacture valuable chemicals through the application of chemistry, math, and engineering principles. Through these processes, they may improve upon existing processes or even create new, more efficient ones. In this activity, students take on the role of chemical engineers by building a valuable compound: silver nanoparticles. These nanoparticles have unique properties that are used in variety of modern applications such as in water treatment, medicine, and electronics. Students also apply the principles of chemistry and engineering to improve the existing manufacturing process.
After this activity, students should be able to:
- Describe the visible signs of a chemical reaction.
- Explain the principle of limiting reactants in chemical reactions.
- Explain why light scattering by nanoparticles produces unexpected colors.
- Refine a chemical process through experimentation.