Would the bat signal actually work?

A good teacher is always looking for an activity to introduce a topic and pique student interest. If the activity surprises or is counter-intuitive to the students’ expectations, that is even better, feeding curiosity and independent exploration.

Zengel and Klales developed a physics lab using basic household items to introduce and expand the topic of optics. The idea for the lab resulted from a late night with a fussy baby and the simultaneous viewing of The Batman.

“When Lieutenant Gordon was standing next to the flood light in one scene, I wondered if that would actually work,” said author Keith Zengel. “The next day we got out some construction paper and scissors, and we realized a lot of fun optics ideas could be introduced with the set-up.”

The students are told to make a bat signal using black construction paper and a desk lamp. They soon realize that holding a bat shape in front of a light aimed at a wall will not produce the iconic bat-shaped silhouette from the movies and comics. At this point, curiosity kicks in and the students start to explore ideas about how light and shadows work. Pinhole lights, inverted images, and focal point discussions naturally follow.

Students enjoy this lab for several reasons — they like the idea of a superhero signal, it’s fun, and there’s no intimidating math or geometry at the beginning. However, movies are far from the only place to find inspiration in physics.

“Sports and toys help demonstrate classical mechanics ideas. Music and instruments can help with electricity and magnetism,” said Zengel. “There are hidden treasures all around!”

Source: “The bat signal,” by Keith Zengel and Anna Klales, The Physics Teacher (2024). This article can be accessed at https://doi.org/10.1119/5.0213457 .