Smartphones and slinkies provide new way to teach students about everyday forces

The physics of force and acceleration have a history of vexing new physics students. Even some physics teachers make mistakes when it comes to the forces at play in everyday situations.

Physicist and educator Ann-Marie Pendrill has developed a lesson example to help students develop an intuition for Newton’s second law. Using smartphone accelerometers and slinky toys can bring an affordable solution to teaching students the relationship between force and acceleration.

“I think it is a common teacher and textbook author misconception that the experience of the body leads to student misconceptions and is best left out of physics teaching,” Pendrill said. “I think it is a more productive approach to analyze the experience and show how it can be visualized or measured with simple toys or smartphone sensors that are now easily available.”

One of her early teaching experiences was of two students unable to resolve their disagrement about acceleration at the lowest point of a swing. One argued that it must be zero because the swing moves fastest at the bottom. The other claimed that there must be a force since you feel heavier there.

She hopes the paper inspires others to expose children to physics principles much earlier than the late teenage years. She is currently updating teaching materials for science days at the Gröna Lund amusement park in Stockholm, where hundreds of classes every year have a chance to use a slinky in a small drop tower.

Source: “Serious physics on a playground swing - with toys, your own body and a smartphone,” by Ann-Marie Pendrill, The Physics Teacher (2023). The article can be accessed at https://doi.org/10.1119/5.0074171 .