University Chemistry ›› 2025, Vol. 40 ›› Issue (1): 256-266.doi: 10.12461/PKU.DXHX202404097

Special Issue:

• Science Education • Previous Articles     Next Articles

The Conqueror of Oil Fires: The Remarkable Foam Guardian

Shaochen Sun, Ruichen Yang, Haoxuan Jiao, Mei Ni, Yancen Liu, Xiangjing Gao   

  1. Department of Basic Courses, China Fire and Rescue Institute, Beijing 102201, China
  • Received:2024-04-15 Accepted:2024-08-12 Published:2025-01-06
  • Contact: Mei Ni, Yancen Liu, Xiangjing Gao E-mail:nimei@cfri.edu.cn;liuyc_cfri@163.com;gaoxiangjing11@126.com

Abstract: Fire poses a severe threat to public safety and property. Enhancing fire safety awareness is crucial for preventing fires and minimizing damage. This paper presents a comprehensive popular science experiment to introduce aqueous film-forming foam (AFFF), which is widely used today. Unlike ordinary foam extinguishers, AFFF contains fluorocarbon surfactants, key components that significantly reduce the surface tension of water and the interfacial tension between water and oil. This allows the AFFF solution to spread over the oil surface, forming a water film and facilitating foam formation. During firefighting, the water film and foam work together to isolate air. In this experiment, several concepts, such as surface tension, the properties of fluorocarbon chains, intermolecular interactions, and combustion conditions through demonstrations, interactions and questioning, have been first introduced. In a live demonstration, the fire-extinguishing effects of AFFF are vividly presented. The experiment is visually impactful, utilizing affordable and readily available instruments and reagents. The educational and interactive aspects of the demonstration effectively combine learning with entertainment, significantly enhancing audience’s scientific literacy and safety awareness.

Key words: Aqueous film-forming foam, Surface tension, Surfactant, Comprehensive popular science experiment