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Lemon Battery Power


  • Project TitleLemon Battery Power
  • Themeelectricity; sources of energy; clean energy
  • Submitted ByJennifer Leonard
  • OrganizationThe Skills Library / For Science Wednesdays
  • Brief DescriptionCreate batteries from lemons and other fruit; discuss the context of energy and electricity.
  • Materials / Resources(1.) 5-7 lemons
    (2.) Pennies
    (3.) Paper clips or safety pins
    (4.) Alligator clip wires
    (5.) Digital clock (ours is from a "Snap Circuits" (TM) kit)
    (6.) Optional: Other small electrical components such as lights and motors
    (7.) Optional: Multimeter (for measuring current)
    (8.) Optional Other types of fruit (oranges, apples, etc.)
    (9.) Worksheets or discussion materials as desired
  • Pre-requisite knowledgeOur group has experience with building circuits with various kits, using conventional batteries, generators and solar batteries. We have also been talking about sources of clean energy, including solar and wind energy.
  • SourcesSeveral websites have instructions for making a lemon battery. I referred primarily to PBS Kids/Zoom.

    I browsed a variety of sources while planning this project and the larger series on climate change and energy. Wikipedia has a useful article (search for lemon battery). The manual from one of our science kits provides an overview of types of energy - mechanical, chemical, heat, etc. (Physics Workshop by Thames and Kosmos).

Units / Activities

  • Opening Discussion (optional)In our Science Wednesday sessions, we open with a conversation about a science topic, talking for about 15-20 minutes while eating after-school snacks.

    Today‘s topic was a continuation of a discussion about climate change and about the expected impact on the city of Boston. We have a map of Boston that shows expected areas of coastal flooding, storm flooding, and high-heat neighborhoods. The map is a conversation starter for a larger conversation about the natural processes that create warming and cooling on the earth, the natural role of carbon dioxide and other gases in the atmosphere, and the rising levels of carbon dioxide and other greenhouse gases that have set off climate change.

    Our conversation focuses also on the science behind typical weather patterns. It also focuses on the idea of optimism .... the idea that we respond to the worry of climate change with not ‘Yikes we are all going to die‘ but with "Yikes what can we do about this.‘

    Throughout the Science Wednesday series, we have been learning about energy and electricity and clean energy sources. Greater use of clean energy sources is a key strategy to address climate change.
    Note that each of our sessions includes an opening discussion and a hands-on project. The discussion and the project may be just loosely connected; but over time, participants see the connections among a wide variety of science topics.
  •  /project643_5789/ClimateChangeBoston.png

    Web Link: Climate Ready Boston (ARC GIS Map)

  • Making the Lemon Battery(1.) Gently squeeze each lemon before starting.
    (2.) Cut two slots in each lemon using scissors or knife.
    (3.) In one slot, insert a copper penny
    (4.) In another slot, insert a paper clip or safety pin
    (5.) Use alligator clip wires to connect the lemons and a digital clock. Connect the lemons by clipping a penny in one lemon to the pin in another lemon; then from the penny in that lemon to the pin in the next lemon, etc. creating a circuit, as shown in the attached picture.
    (6.) See if the digital clock turns on. If not, do any and all of the following to troubleshoot. First, reverse the connection to the digital clock. Squeeze the lemons to make sure the juice can flow around inside the lemon. Check the connections to make sure you‘ve made a full circuit. If it still doesn‘t turn on, add another lemon to the circuit.

    Once you have gotten the digital clock to turn on, you can experiment by adding more lemons or adding or substituting other types of fruit, such as oranges or apples, to the circuit. You can also try attaching other electronic components, including LED lights or motors, or attaching a multi-meter that measures current. You will see that the current is very weak. The digital clock is an ideal component because it needs only a weak power source.

    The photo below shows three lemons plus one orange connected to the digital clock. We also successfully added an apple to the circuit.
  •  /project643_5789/lemon_battery.jpg/project643_5789/lemon_battery_diagram.png

    Web Link: ZOOM . activities . sci . Lemon Battery | PBS Kids

  • Overview of the Lemon Battery Project / Wrap-Up DiscussionBefore and/or after building the lemon battery, students talk about the project. Our group was already familiar with the idea of a lemon battery and had asked to make one, so we built the battery before discussing the theory behind it, and talked about the theory afterwards.

    (1.) What sources of energy are we familiar with? From earlier units, we are familiar with at least three... energy is generated from heat (solar, burning fuels); mechanical (windmill, hand-turned generator); or chemical (traditional battery, lemon battery). The lemon battery is a chemical reaction, like a regular battery. (Other forms of energy include kinetic energy, electromagnetic energy and nuclear energy.)

    (2.) What makes the lemon battery work? We have put two different types of metal into an acidic fruit. A very simple explanation is that there is a chemical reaction between the copper and acid in the lemon, and another chemical reaction between the metal pin and the acid. These reactions get the electrons excited and moving around. The electrons travel through the lemon and through the wires creating an electrical circuit.
    The Wikipedia article provides a brief overview of the chemical reaction. The article also highlights the ‘lessons learned‘ from this project from the point of view of elementary, middle and high school courses.

    Web Link: Lemon battery - Wikipedia

    Web Link: Physics Workshop Manual

Tags = science | Electricity-and-Circuits | Science-Wednesdays | Subject = Science | Grade Level = Elem, MS | Time Period = | Program/Funding = |
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