Nerf projectiles illustrate atomic scattering in the classroom

Ever since 1908 Nobel prize winner in chemistry Ernest Rutherford analyzed the scattering of alpha particles from a thin gold foil and discovered that atoms contain tiny, positively charged nuclei, physicists have tried to emulate him. By designing large particle accelerators for scattering experiments, they aim to discover new particles, study the forces between them, and otherwise examine the subatomic world.

It’s unlikely Rutherford could have imagined the subatomic scattering principles he uncovered would become illustrated with … Nerf projectiles.

In contrast to classic, often more abstruse, accelerator experiments, Fletcher et al. recently developed an updated – and irresistibly fun – educational activity to demonstrate the basics of particle scattering experiments. Building on a popular commercial experiment from the 1960s, which featured ball bearings fired at cylindrical targets, the new experiment replicates the macroscopic, two-dimensional analogy for scattering using Nerf projectiles and stationary one-gallon paint cans.

“By doing this experiment using macroscopic objects instead of subatomic particles, students can get a better feel for how scattering works,” said author Kurt Fletcher, who wrote the study with two undergraduate students. “In our version, Nerf projectiles are fired at a stationary 1-gallon paint can and bounce off at different angles to be caught in cloth bags that are arranged in a large circle around the target.”

By firing the Nerf projectiles evenly across the target and producing a graph of the number of projectiles scattered at each angle increment, students can determine the target’s radius without using a ruler.

Altogether, the experiment setup simplifies many of the complexities of atomic scattering for students, reduces the amount of time required to obtain data, and all but guarantees a popular class.

Source: “The projectile scattering apparatus - A modern update to a classic experiment,” by Kurtis A. Fletcher, Nicole M. Lallier, and Jack M. Masman, The Physics Teacher (2023). The article can be accessed at http://doi.org/10.1119/5.0064389 .