Why Do Dead Batteries Bounce? Chemistry, of Course!

Bouncing batteries

Did you know there is a simple test you can do to see if an alkaline battery is fresh or dead?1,2 All you need to do is bounce the bottom of a battery onto a hard, flat surface. If the battery is fresh it won’t bounce very well. If the battery is dead, it will bounce very high. Check it out in the video.3

Guess what causes this difference in bouncing ability between fresh and dead batteries? Chemistry, of course!

The chemical reaction that powers batteries involves the conversion of zinc metal, manganese (IV) oxide and water into zinc oxide and manganese oxide hydroxide:1,2

Zn(s) + 2 MnO2(s) + H2O(l) à ZnO(s) + 2 MnOOH(s)        Equation 1

It turns out that ZnO is a very bouncy material. Indeed, adding ZnO to the interior of golf balls increases the distance they travel when they are hit.4 Thus, the formation of increasing amounts of ZnO as a battery is used increases the bounciness of the battery. Notice that water is also consumed as a battery is used. This also probably contributes to the increased bounciness of a dead battery in the following way: when a dropped battery strikes a surface, its kinetic energy of motion can be more easily dispersed throughout a liquid than a solid. Thus, the water present in a fresh battery leaves less kinetic energy for rebound. This water is consumed as the battery is used, causing the interior of a dead battery to be more-solid like. Less liquid water available in a dead battery does not allow for such kinetic energy to be dispersed, leaving more energy for rebound.

In addition to differences in bouncing ability, it is quite easy to compare differences in the contents of fresh and dead batteries. To do so, try cutting open a fresh and a dead battery with a pair of PVC pipe cutters to inspect the differences between the two (SEE CAUTION BELOW). You will likely note that a fresh battery oozes a bit upon cutting it open, while a dead battery does not. This observation is consistent with the fact that water is consumed as a battery operates (Equation 1). You might notice that the inner portion of a fresh batter appears to be more silvery in color, while the inner portion of a dead battery appears more whitish grey. These observations are consistent with the conversion of Zn to ZnO as a battery operates: zinc is a silvery metal, while zinc oxide is white.

It is also possible to use a simple chemical test to distinguish between the presence of Zn and ZnO in fresh and dead batteries. The inner portion of fresh batteries reacts with hydrochloric acid to produce a gas. Again, that’s because the inner portion of fresh batteries contains a lot of unreacted Zn metal:

Zn(s) + 2HCl(aq) à ZnCl2(aq) + H2(g)                     Equation 2

However, the inner portion of a dead battery contains mostly ZnO, which produces no gas upon reaction with hydrochloric acid:

ZnO(s) + 2 HCl(aq) à ZnCl2(aq) + H2O(l)               Equation 3

Because of this difference, one would expect larger gas H2 production when mixing the inner portion of fresh batteries vs. dead batteries with HCl(aq).

The video below illustrates how to carry out these particular experiments.

I hope you consider trying out these experiments in your classroom. Drop a note in the comments if you try them out for your students. Happy experimenting!

CAUTION: Wear safety goggles and gloves. The experiments described herein are only intended for Zn-MnO2 alkaline batteries. Do not attempt to cut open any other type of batteries as the contents very likely contain hazards not described here. The contents of Zn-MnO2 alkaline batteries contents are caustic. Use caution when cutting open as the contents may spray. If the battery appears to be getting very warm when being cut open, stop cutting immediately and promptly remove the PVC cutter from the battery.

References

1. Bhadra, S.; Hertzberg, B. J.; Hsieh, A. G.; Croft, M.; Gallaway, J. W.; Van Tassell, B. J.; Chamoun, M.; Erdonmez, C.; Zhong, Z.; Sholkapper, T.; Steingart, D. A. The relationship between coefficient of restitution and state of charge of zinc alkaline primary LR6 batteries. J. Mater. Chem. A. 2015, 3, 9395–9400.

2. Hall, J. M.; Amend, J. R.; Kuntzleman, T. S. Experiments To Illustrate the Chemistry and Bouncing Ability of Fresh and Spent Zinc–Manganese Oxide Alkaline Batteries. J. Chem. Educ. 201693, 676-680.

3. Kuntzleman, T. S. , Tommy Technetium YouTube Channel, published 2/1/2019. (accessed 3/27/19).

4. Sullivan, M. J.; Nesbitt, R. D. Golf Ball Comprising a Metal, Ceramic, or Composite Mantle or Inner Layer. 2003, U.S. Patent 6,612,939 B1.

 

Safety

General Safety

For Laboratory Work: Please refer to the ACS .  

For Demonstrations: Please refer to the ACS Division of Chemical Education .

Other Safety resources

: Recognize hazards; Assess the risks of hazards; Minimize the risks of hazards; Prepare for emergencies

 

NGSS

Constructing explanations and designing solutions in 9–12 builds on K–8 experiences and progresses to explanations and designs that are supported by multiple and independent student-generated sources of evidence consistent with scientific ideas, principles, and theories.

Summary:

Constructing explanations and designing solutions in 9–12 builds on K–8 experiences and progresses to explanations and designs that are supported by multiple and independent student-generated sources of evidence consistent with scientific ideas, principles, and theories. Construct and revise an explanation based on valid and reliable evidence obtained from a variety of sources (including students’ own investigations, models, theories, simulations, peer review) and the assumption that theories and laws that describe the natural world operate today as they did in the past and will continue to do so in the future.

Assessment Boundary:
Clarification:

Modeling in 9–12 builds on K–8 and progresses to using, synthesizing, and developing models to predict and show relationships among variables between systems and their components in the natural and designed worlds.

Summary:

Modeling in 9–12 builds on K–8 and progresses to using, synthesizing, and developing models to predict and show relationships among variables between systems and their components in the natural and designed worlds. Use a model to predict the relationships between systems or between components of a system.

Assessment Boundary:
Clarification:

Constructing explanations and designing solutions in 9–12 builds on K–8 experiences and progresses to explanations and designs that are supported by multiple and independent student-generated sources of evidence consistent with scientific ideas, principles, and theories.

Summary:

Constructing explanations and designing solutions in 9–12 builds on K–8 experiences and progresses to explanations and designs that are supported by multiple and independent student-generated sources of evidence consistent with scientific ideas, principles, and theories. Construct and revise an explanation based on valid and reliable evidence obtained from a variety of sources (including students’ own investigations, models, theories, simulations, peer review) and the assumption that theories and laws that describe the natural world operate today as they did in the past and will continue to do so in the future.

Assessment Boundary:
Clarification:

Planning and carrying out investigations in 9-12 builds on K-8 experiences and progresses to include investigations that provide evidence for and test conceptual, mathematical, physical, and empirical models.

Summary:

Planning and carrying out investigations in 9-12 builds on K-8 experiences and progresses to include investigations that provide evidence for and test conceptual, mathematical, physical, and empirical models. Plan and conduct an investigation individually and collaboratively to produce data to serve as the basis for evidence, and in the design: decide on types, how much, and accuracy of data needed to produce reliable measurements and consider limitations on the precision of the data (e.g., number of trials, cost, risk, time), and refine the design accordingly.

Assessment Boundary:
Clarification:

Matter and its Interactions help students formulate an answer to the question, “How can one explain the structure, properties, and interactions of matter?” The PS1 Disciplinary Core Idea from the NRC Framework is broken down into three subideas: the structure and properties of matter, chemical reactions, and nuclear processes. Students are expected to develop understanding of the substructure of atoms and to provide more mechanistic explanations of the properties of substances. Chemical reactions, including rates of reactions and energy changes, can be understood by students at this level in terms of the collisions of molecules and the rearrangements of atoms. Students are able to use the periodic table as a tool to explain and predict the properties of elements. Using this expanded knowledge of chemical reactions, students are able to explain important biological and geophysical phenomena. Phenomena involving nuclei are also important to understand, as they explain the formation and abundance of the elements, radioactivity, the release of energy from the sun and other stars, and the generation of nuclear power. Students are also able to apply an understanding of the process of optimization in engineering design to chemical reaction systems. The crosscutting concepts of patterns, energy and matter, and stability and change are called out as organizing concepts for these disciplinary core ideas. In the PS1 performance expectations, students are expected to demonstrate proficiency in developing and using models, planning and conducting investigations, using mathematical thinking, and constructing explanations and designing solutions; and to use these practices to demonstrate understanding of the core ideas.

*More information about this category of NGSS can be found at 

Summary:

"Matter and its Interactions help students formulate an answer to the question, “How can one explain the structure, properties, and interactions of matter?” The PS1 Disciplinary Core Idea from the NRC Framework is broken down into three subideas: the structure and properties of matter, chemical reactions, and nuclear processes. Students are expected to develop understanding of the substructure of atoms and to provide more mechanistic explanations of the properties of substances. Chemical reactions, including rates of reactions and energy changes, can be understood by students at this level in terms of the collisions of molecules and the rearrangements of atoms. Students are able to use the periodic table as a tool to explain and predict the properties of elements. Using this expanded knowledge of chemical reactions, students are able to explain important biological and geophysical phenomena. Phenomena involving nuclei are also important to understand, as they explain the formation and abundance of the elements, radioactivity, the release of energy from the sun and other stars, and the generation of nuclear power. Students are also able to apply an understanding of the process of optimization in engineering design to chemical reaction systems. The crosscutting concepts of patterns, energy and matter, and stability and change are called out as organizing concepts for these disciplinary core ideas. In the PS1 performance expectations, students are expected to demonstrate proficiency in developing and using models, planning and conducting investigations, using mathematical thinking, and constructing explanations and designing solutions; and to use these practices to demonstrate understanding of the core ideas."

Assessment Boundary:
Clarification:

Students who demonstrate understanding can construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.

*More information about all DCI for HS-PS1 can be found at  and further resources at .

Summary:

Students who demonstrate understanding can construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.

Assessment Boundary:

Assessment is limited to chemical reactions involving main group elements and combustion reactions.

Clarification:

Examples of chemical reactions could include the reaction of sodium and chlorine, of carbon and oxygen, or of carbon and hydrogen.