Grade Level: 4th Grade | Duration: 50 minutes
This hands-on STEAM laboratory guides students through building a functional coin battery from everyday materials—pennies, nickels, and saltwater. Students investigate how chemical energy converts to electrical potential energy by constructing battery cells, measuring voltage with a voltmeter, and ultimately attempting to power an LED light. The lesson aligns with Alabama College and Career Ready Science Standards for Energy, requiring students to plan and carry out investigations demonstrating energy transfer and to design, construct, and test energy conversion devices.
Learning Objectives
Students will conduct an investigation providing evidence that chemical energy can be converted to potential energy in the form of a battery. They will build a battery and test its efficiency by measuring voltage and determining whether the device produces enough power to illuminate a small LED light bulb.
Background & Scientific Concepts
The lesson opens with context about energy storage’s critical role in modern life, from cell phones and laptops to electric vehicles. Solar panels use lithium-ion batteries to store solar energy for later use when the sun isn’t shining. Lithium is a lightweight metal that allows electric current to pass through easily, and lithium ions make batteries rechargeable because their chemical reactions are reversible.
The core scientific principle: A battery stores electrical energy in chemical form and converts it back to electricity. Every battery contains two terminals (typically different metals) plus an electrolyte solution. The electrolyte allows electrical charge to flow, creating potential energy (voltage) for powering devices.
In this specific experiment, the saltwater solution serves as the electrolyte, activating a chemical reaction between the two different metal coins. Because pennies and nickels contain different metals, one reacts more strongly than the other, creating a voltage difference and an imbalance of electrons. This imbalance produces a force—a power source—that drives electrical current through the closed circuit when the voltmeter connects to each end of the stack. Chemical energy converts to potential energy, which can illuminate an LED if sufficient voltage is produced.
Activities & Structure
Engage Phase (10 minutes) – “Match it up!”
Students work in groups using the Building a Battery Matching Cards to learn experimental terminology and understand how the battery-building process works. They first match 8 vocabulary term cards to their corresponding 8 definition cards. After the teacher checks or discusses correct answers, students organize the 6 experiment process cards in correct sequential order showing how the battery works. The teacher again verifies answers to ensure conceptual understanding before hands-on work begins.
Explore Phase (35 minutes) – “Build it!”
Students complete the Essential Question and Hypothesis sections of their Lab Report. The teacher can guide the class in formulating these collectively or allow groups to develop their own; it’s suggested that the teacher at least guides the Essential Question development. Students then follow the Lab Guide’s step-by-step instructions:
- Step 1: Clean 8 pennies and 8 nickels with soap, then dry them thoroughly with paper towel.
- Step 2: Using a pencil and penny as template, trace and cut 10 paper towel circles slightly larger than penny size.
- Step 3: Soak paper towel circles one at a time in the saltwater solution. Critical note: Circles should be wet but not dripping—excess electrolyte can create short circuits. Students should press out excess liquid between thumb and finger.
- Step 4: Assemble 8 battery cells by laying out nickels, placing soaked paper circles on each, then placing pennies on top. Critical warning: The penny must touch only the paper, not the nickel directly, or a short circuit will prevent the battery from working. Each penny-paper-nickel stack becomes an individual battery cell.
- Step 5: Test a single cell using the voltmeter (teacher assists with proper DC voltage setting showing at least one decimal point). One lead touches the nickel, the other touches the penny. A working cell should show 0.25–0.50 volts DC.
- Step 6: Stack all battery cells together maintaining the penny-paper-nickel pattern to create one larger battery. Test total voltage with the voltmeter—it should be higher than a single cell.
- Step 7: Connect wires to the top and bottom coins of the assembled battery (tape can secure connections). Connect the battery wires to the LED light wires. Students observe whether their battery produces enough voltage to illuminate the LED. If initial attempts fail, groups can combine their batteries by carefully stacking them together, measuring voltage as they add each group’s contribution until achieving sufficient power.
Throughout construction, students record procedures and observations on their Lab Report handout.
Evaluate Phase (5 minutes) – “Make Conclusions!”
Students complete the Discussion/Conclusions section of their Lab Report, referring back to their original hypothesis and documenting final thoughts about the experiment. Groups can share their conclusions with each other or participate in whole-class discussion.
Materials Included (Printable Files)
Lab Guide: Building a Battery (3-page PDF)
Pages 1-2 feature the step-by-step Lab Guide with battery icon header, grade level indicator, and seven numbered steps with materials lists for each. Instructions include helpful icons (bottle for saltwater, coin stacks, lightbulb for LED testing) and warning callouts for critical steps. “Ask your teacher to:” sections indicate where students need voltmeter assistance. The guide builds excitement with the transitional prompt “Are you ready to GLOW to the next step?” before the final LED testing phase.
Page 3 contains the Lab Report template with stylized header, fields for Scientist Name and Date, sections for: Essential Question (“What do you want to learn from your experiment?”), Hypothesis with sentence starter “I think ___ will ___ because ___”, Procedures/Observations with large open space and prompt “Draw a picture or write notes on the steps of your experiment!”, and Discussion/Conclusions (“What did you learn from your experiment? Think back to your hypothesis!”).
Building a Battery Matching Cards (5-page PDF)
Pages 1-3 contain 8 vocabulary matching card sets with illustrated terms and definitions:
- Electric charge (battery icon with +/- symbols): The basic physical property of matter that causes it to experience a force in an electromagnetic field; can be positive, negative, or zero
- Electrolyte (bottle with charged droplet icon): A liquid that contains particles carrying charge
- Electrochemical reaction (test tube pouring into flask icon): A type of chemical reaction that creates electrons
- Electrons (atom diagram with – particles orbiting + center): A particle with a charge of negative electricity
- Electric current (electrical plug with + particles icon): A stream of charged particles all moving in the same direction
- Electrode (stacked coins/discs icon): A solid metal conductor that carries electric current into non-metallic substances such as a liquid
- Voltage (warning triangle with lightning bolt): The amount of electrical force (or potential energy) between two units in a circuit
- Voltmeter (meter device with leads icon): An instrument that measures electric potential in volts
Pages 4-5 contain 6 sequential process cards showing the battery operation flow with directional arrows between each step:
- Saltwater solution + different metals (bottle and coin stack icons) →
- Causes chemical reaction (test tube and flask icons) →
- Produces voltage difference (warning triangle with lightning) →
- Electrons move through closed circuit (atom diagram) →
- Electrical current is produced (plug with + symbols) →
- Electrical potential can be measured (voltmeter and lightning bolt icons)
Cards should be cut apart along dotted lines and shuffled before distributing to groups.
PowerPoint Presentations (2 files)
Two PowerPoint presentations are included for teacher instructional support: “Building_a_Battery_NCTHS_4th.pptx” and “STEAM_Lab_Building_a_Battery.pptx” (specific slide contents provide visual aids for lesson delivery).
Materials to Gather (Per Class)
- 1 voltmeter (can be shared between groups)
- 1 small LED light (approximately 1.4V–1.8V, current-compatible with coin battery, with wire insulation stripped from ends)
- Additional wiring to facilitate connections
Materials to Gather (Per Group of 3-4 Students)
- 8 pennies
- 8 nickels
- Pencil for tracing
- Mild soap for coin cleaning
- Saltwater solution (approximately ¼ cup water with enough salt mixed in that a few grains no longer dissolve after stirring)
- 1 small bowl for saltwater solution
- 1 large paper towel
- Scissors
- 1 set of Building a Battery Matching Cards (cut and shuffled)
Materials to Gather (Per Student)
- 1 copy of Lab Guide: Building a Battery handout
This engaging laboratory demonstrates electrochemistry principles through tangible experimentation, connecting abstract concepts about energy storage to students’ everyday experience with batteries while building toward the exciting payoff of lighting an LED with student-constructed power sources.
Files Included:
- Main lesson plan (.docx)
- Lab Guide handout (3-page PDF with step-by-step instructions and lab report template)
- Building a Battery Matching Cards (5-page PDF with vocabulary and process flow cards)
- Two PowerPoint presentations for teacher use
Resources & Downloads
STEAM Lab: Building a Battery Archive
This .zip files contains all the files listed above.
External Link