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ERIC Number: EJ1177774
Record Type: Journal
Publication Date: 2018-May
Pages: 5
Abstractor: As Provided
ISSN: ISSN-0031-921X
"Ripples" in an Aluminum Pool?
Rohr, James; Wang, Si-Yin; Nesterenko, Vitali F.
Physics Teacher, v56 n5 p281-285 May 2018
Our motivation for this article is for students to realize that opportunities for discovery are all around them. Discoveries that can still puzzle present day researchers. Here we explore an observation by a middle school student concerning the production of what appears to be water-like "ripples" produced in aluminum foil when placed between two colliding spheres. We both applaud and explore the student's reasoning that the ripples were formed in a melted aluminum pool. Using relatively simple experiments, we argue that the impact energy is not enough to melt the aluminum. Furthermore, we demonstrate that the same pattern can be observed in quasi-static experiments, suggesting "wrinkles" is a better descriptor than "ripples." Curiously, we could not find a single reference in the research literature to this particular observation. A research effort to explore this more rigorously is well beyond the scope of this article. Nevertheless, we can say that although not commonly observed, the generation of instability patterns is typical for high strain flow of many ductile materials, reflecting a fundamental property of nature, that the path of energy flow from macroscale to microscale often involves unstable behavior and pattern formation.
American Association of Physics Teachers. One Physics Ellipse, College Park, MD 20740. Tel: 301-209-3300; Fax: 301-209-0845; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Evaluative
Education Level: Middle Schools
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Grant or Contract Numbers: N/A