Cornstarch experiment provides guidance for industrial applications

Cornstarch suspensions, known colloquially as “oobleck,” are a common experiment for kids learning about non-Newtonian fluids. But beyond the classroom, cornstarch suspensions are also showing promise for a range of commercial applications from food engineering to bulletproof vests.

To date, many experiments have looked at cornstarch suspension’s shear thickening behavior, which is a key characteristic for its use in ballistic materials. However, these studies only focus on fixed particle concentrations. Expanding this work to a range of particle concentrations, Ning et al. conducted a hammer drop experiment that provides a theoretical framework for industrial applications.

“Cornstarch, a ubiquitous and inexpensive food material in daily life, holds immense potential if its remarkable applications were to be thoroughly and extensively studied,” said author Yanhao Ning. “Additionally, this experiment is remarkably simple with high reproducibility — any household can easily recreate it.”

The experiment used low mass ratio from 1:10 to 1:1 as well as high mass ratio from 1:1.02 to 1:1.2 of cornstarch mixed with pure water. The researchers dropped a hammer weight on the mixtures and measured the peak force of the impact when the hammer reached the bottom of the mixture.

The results in low mass ratio suspensions did not show much change in resistance, which was similar to the resistance of water. Yet, above a ratio of 1:1.1, the suspension exhibited solid-like properties that caused the peak force to drop dramatically.

The findings help researchers better understand concentration-dependent effects on the mechanical properties of non-Newtonian fluids. This work could help enable applications of cornstarch suspensions in safety engineering such as ballistic armor, sports safety gear, and structural dampers for infrastructure, among other things.

Source: “Influence of concentration on dynamic penetration and mechanical properties of cornstarch suspensions,” by Yanhao Ning, Quanle Zou, Xujing Tan, Qican Ran, Qingsong Li, Physics of Fluids (2025). The article can be accessed at https://doi.org/10.1063/5.0265631 .