When Silicon Talks: Refraction Equation Practice & Bio Lab Work
Porous silicon has many measurable optical properties that make it a useful material.Copyright 2013 Caleb Swartz, Vanderbilt University
In the first half of this two-part activity, students practice solving problems involving refraction using the index of refraction and Snell's law equations; they mathematically solve for precise angles and speeds caused by refraction. In the second half of the activity, a hands-on lab, they apply the analytical skills required by the problem set to reflectance measurements of porous silicon thin films, including how reflectance measurements would change if various aspects of the film were altered. Students predict the data output in the form of reflectance measurements when samples are altered, which connects to the idea of being able to make predictions about the data output of a biosensing thin film that couples with a target molecule.
In order to create workable products, engineers need more than basic information about physical concepts and how to manipulate them to perform tasks. More specifically, the information must be quantified or measurable in numerical form through precise analysis in order to ensure that exact inputs produce exactly the same outputs every time a task is performed. In this activity, students tackle this aspect of engineering as they solve problems for precise angles and speeds, and predict data output (reflectance measurement) when samples are altered.
After this activity, students should be able to:
- Accurately solve a refraction problem for a missing angle or index of refraction.
- Explain in at least two complete sentences how connection with a target molecule alters the data output of a porous silicon thin film.