What’s Your Angle? Assessing Wave Refractions
Students shine the laser light as part of the experiment.Copyright Gunjan Gupta, 2023. Picture taken in the classroom during the lab activity.
Students observe wave refraction in different mediums. They trace the path of light waves of a laser entering a medium and exiting the medium. Then they measure the angle of the refracted ray using a protractor to get an understanding of the concepts of how refraction works in different mediums. By the end of the lesson, students will be able to identify which substance refracted light the most and hypothesize a pattern of refraction based on the densities of the substance.
In engineering, it is not enough to merely understand the concepts or ideas behind physical phenomena such as refraction. If engineers want to take a physical law of the universe and turn it into a product that performs a task, then the phenomenon must be quantifiable—they must be able to assign a mathematical function or equation to it that accurately predicts an outcome if the input parameters are manipulated purposefully. In a way, engineers are dictating the setup and letting nature take its course to a conclusion that the engineers can foresee from the start. Similarly, students play the role of engineers in this lesson when they use an equation for refraction (Snell's law) to predict what light will do given a specific scenario. They further act as engineers when they use this equation to define what a biosensor can be made to do under given conditions. 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 when samples are altered.
After this activity, students should be able to:
- Explain that light refracts differently in different mediums.
- Accurately measure the angle of refraction in different mediums.
- Find the index of refraction using Snell’s law.