Boosting battery performance (without subtitles) © Siemens Stiftung 2017 CC BY-SA 4.0 international

Boosting battery performance (without subtitles)


Video (04:33 minutes, without sound):
The experiment with the Cu/Zn element shows that a battery reaches its full capacity only when Cu2+ ions are present.

English, German
Video (69.4 MByte)
The combination of two metals is often misconstrued as an essential feature of electrochemical elements (batteries, accumulators). In reality, however, an element consists of the combination of two metal redox pairs. The zinc/copper battery often used in the classroom – made with fruit, vegetables, or even with acid or saltwater – is in reality a zinc/hydrogen element (Zn/Zn2+ and H/H+). The voltage and power are therefore less than the values for Zn/Cu. The battery does not become a Zn/Cu element (Zn/Zn2+ and Cu/Cu2+) until the copper half-cell also contains copper ions from the dissolved copper sulfate. Then the element reaches full voltage and power.

The film is also available on the media portal as a version in which explanations are displayed as subtitles for some scenes: “Boosting battery performance (with subtitles)."

Information and ideas:
The experimentation instructions for “A3 Lemon batteries and other batteries" contain two subexperiments (4 and 5) that involve copper sulfate. For safety reasons, however, some teachers may not want to allow any experiments involving copper sulfate in their classrooms. In this case, the teachers can show this video with subexperiment 4 as an alternative. This allows the overall experiment consisting of subexperiments set up as many didactic steps to be completed systematically anyway.
The teacher should point out to the students that the simplified experiment shown in the film works without a separator. Detailed experimentation instructions are found in the medium “A3 Lemon batteries and other batteries (student instructions)" for subexperiment 4, which is available on the media portal. The technical explanation is found in the medium “A3 Lemon batteries and other batteries (teacher instructions)."
Chemistry; Physics; Technology
Grade 5 to 6; Grade 7 to 9; Grade 10 to 13
Middle/high school
Acids; Base (chemistry); Battery; Chemical reaction; Direct current; Hydrogen; Salt
Siemens Stiftung Media Portal
MediaHouse GmbH
© Siemens Stiftung 2017
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