“Light moves in the form of waves” and is “reflected, refracted, and absorbed” are all traditional statements of light energy that become staples of assessment for student understanding. But whether students can apply this understanding is a big question. The NGSS asks students to “use and develop models to describe phenomena and demonstrate understanding.” Knowing that the concept of light as a wave requires an abstract understanding of electromagnetic radiation, I challenged students to demonstrate their knowledge using a model of light moving as particles with the help of the “Color Vision” PhET simulation.
Before introducing this model, students had observed several other light phenomena including prisms and spectroscopes splitting white light into the visible spectrum, water filled cups “breaking” a pencil, and mirrors reflecting their own image. They had also read about light energy and how light “moves in straight lines” and can be “reflected, refracted, and absorbed.” With students broken down into four groups, I challenged each group to explain how the “particles of colored light known as photons” behaved when they approached different materials of familiarity: a transparent window, a stained-glass window, a magnifying glass, and black construction paper.
Students argued within their groups, challenging eachothers’ ideas before coming to a consensus which was explained before the class. While the model did not have windows or lenses to drop in the way of their light photon stream, we were able to draw these on the board, and students were able to explain their understanding with some confirmation at the end through the instructor. The black paper and stained-glass was easy enough to observe and check for understanding through the PhET model.
The videos speak for themselves! Students were more than up for the challenge and seeing students apply their knowledge to new models only confirmed that the practice of using models is more than manageable for upper-elementary students, its a boost to instructional opportunities and assessing student understanding!