Foam fire extinguisher (task)
The task of finding out how a foam fire extinguisher works should follow experience gained in an experiment on how sodium bicarbonate and citric acid react with each other.
Incremental hints for answering this task are available under “Foam fire extinguisher (hints for printing)” or “Foam fire extinguisher (interactive hints)” on the media portal of the Siemens Stiftung. The worksheet includes QR codes for using the interactive hints online and viewing the solution.
Explanations of the experiment for the teacher are found in “Foam fire extinguisher (teacher information).”