Electric Vehicles

What are Electric Vehicles?

Build an electric car that can zip and zoom! Learners assemble a working circuit from a battery, a motor, and a pair of gears, then design a unique vehicle platform with axles, bearings, and wheels. This is the only Spark where learners close a real electric circuit and feel the rush of a motor spinning a gear they just installed — then they swap the wires and watch the vehicle roll backward, discovering polarity through play.

Time Needed:
15-40 minutes. If used during an event, Electric Vehicles can be set up in a 15-minute quick-build activity station.
Grade Level:
Grade 4 and up
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Overview

Electric Vehicles is a circuits-and-engineering Spark for Grade 4 and up. Each learner gets a cardboard platform, two wooden-dowel axles, a sheet of die-cut foam wheels, bushings, and bearings, a DC motor already attached to its clip, a AA battery, a yellow battery band, a plastic gear wheel, four plastic connectors, and two paper tubes — everything they need to build a running electric car in about 40 minutes.

The basic build walks learners through nine moves: break apart the cardboard base, snap the motor clip into place, assemble the first axle with a gear wheel that meshes with the motor gear, connect the battery through a yellow rubber band that holds the wires in place, test the vehicle and swap the wire polarity to reverse direction, troubleshoot friction and gear alignment, then build a second rear axle and attach it to the base using plastic pincher connectors. Once the vehicle rolls, learners deconstruct it and iterate — redesigning with paper tubes, straws, and scissors to make their car the smallest, the fastest, a three-wheeler, or a circle-driving creation.

Materials

Each learner recieves
  • One cardboard vehicle platform (breaks into a square base plus a second axle bar)
  • Two wooden dowel axles
  • A die-cut foam sheet with wheels, bushings, and bearings
  • One AA battery
  • One yellow rubber battery band
  • A DC motor with red and black wires (pre-attached to a motor clip)
  • One plastic gear wheel
  • One plastic wheel
  • Four plastic connectors (pinchers)
  • Two paper tubes
  • A printed visual guide sheet
  • A reclosable storage bag
What you need to provide

Scissors (not included) are highly recommended. Learners use them to cut the paper tubes into unique lengths during the Iterate step and to shape straws or other materials for creative redesigns.

Optional resources
  • Extra straws, paper scraps, or cardboard for learners who want to extend their vehicle during the Iterate step
  • Masking tape for reinforcing creative additions to the platform
  • A smooth floor or long table for race testing
  • A stopwatch or phone timer for timed races between classmates
  • Replacement AA batteries for learners whose batteries die mid-lesson

Key Challenges

  1. Close a working electric circuit. Learners connect the motor's red and black wires to the correct ends of a AA battery and hold them in place with a yellow rubber band, turning an open circuit into a closed one that spins the motor.
  2. Mesh a gear train so the wheels turn. Learners align the gear wheel on the axle with the motor gear, using bushings and a foam bearing to hold the axle in place at exactly the right angle. A misaligned gear spins freely but delivers no power.
  3. Swap polarity to reverse direction. Learners test the basic build, then switch the battery wires and observe how the vehicle now rolls the opposite direction — discovering how wire placement controls the flow of electricity.
  4. Iterate a unique design. Every Electric Vehicle should look different. Learners deconstruct the basic build and use paper tubes, straws, and creative additions to redesign — racing classmates, going in circles, or combining cars.

Learner Goals

MUST
  • Assemble the first axle correctly so the gear wheel on the axle meshes with the motor gear.
  • Connect the motor's red and black wires to the AA battery using the yellow rubber battery band.
  • Demonstrate that their completed circuit makes the motor spin the wheels.
SHOULD
  • Explain the difference between an open circuit and a closed circuit, and point to where the electricity is flowing in their vehicle.
  • Swap the battery wires and predict what will happen before they test — observing how polarity reverses the direction of the motor and the vehicle.
  • Troubleshoot common problems by wiggling the bearing to reduce friction or pushing the foam bearing to realign the axle when the gears don't mesh.
COULD
  • Redesign their vehicle during the Iterate step using paper tubes, straws, and scissors to create something totally different from the basic build.
  • Compare their design to a classmate's and discuss which design choices affect speed, stability, or straight-line travel.
  • Explain how the energy from the battery transfers through the wires to the motor and then through the gear train to the wheels — identifying each step of the energy transfer.

Extension Activities

  • Smallest Vehicle Challenge: What is the smallest Electric Vehicle you can build that still rolls? Learners strip away everything non-essential and see how compact they can make their basic build while keeping the circuit and gears functional.
  • Three-Wheel Challenge: Can you design a vehicle with just three wheels? Learners think about balance, stability, and how a missing wheel changes the way the vehicle drives.
  • Circle-Driving Challenge: Can you make your vehicle go in circles instead of a straight line? Learners experiment with weight distribution, offset wheels, or dragging one side to create controlled turning.
  • Vehicle Combination Challenge: Work with a classmate (or two) to combine multiple Electric Vehicles into one. What does a two-battery, four-motor vehicle do that a one-motor vehicle cannot?
  • Race Challenge: Set up a simple track or straight line and race redesigned vehicles. Discuss afterward what design choices made the fastest cars fastest — weight, wheel friction, battery contact, or something else.
  • Paper-Tube Body Challenge: Use the two paper tubes (and scissors) to build a new body for the Electric Vehicle. Learners cut and attach the tubes to give their cars a totally different shape.

Before You Start

Watch Our Educator Guide!
Pre-Activity Questions
3rd - 5th Grade
  1. What do you think it means when we say electricity "flows" through a wire?
  2. Have you ever seen a real electric vehicle — a car, a scooter, or a toy? What do you notice about how it moves compared to a gas-powered one?
  3. If you had a battery, a motor, and two wires, what would you need to do to make the motor spin?
6th - 8th Grade
  1. What is a circuit, and what do you think needs to be true for a circuit to be "closed"?
  2. Why do batteries have a positive (+) and a negative (–) end? What do you think would happen if you swapped which side the wires touched?
  3. When you see a gear turning another gear, what is actually being transferred from one to the other?
Pro Tips
  • Pre-teach the circuit concept before building. In the educator video, Nataliia spends a full minute before any cardboard is broken explaining that the motor has a red positive wire and a black negative wire, the battery has a positive and negative side, and connecting wires to opposite ends creates a circuit. Walking learners through this up front makes Step 5 (Connect the Battery) several times faster because they already know what they are trying to do.
  • Save the tab. In Step 1, the tab in the middle of the square base looks like scrap — it is not. It is the piece that locks the motor in so it does not fall out mid-build. Tell learners this before they start breaking cardboard or half of them will throw it away.
  • Do not lose the foam pieces. Every piece on the die-cut sheet has a job. The leftovers come in handy during the Iterate step, so have learners pop them all out and keep them together from the start.
  • Push AND twist, at an angle. Getting the gear wheel onto the axle is the single trickiest move in the build. Hold the axle near the end, push the gear down slowly, and add a quarter-twist at the same time. Angle helps. Resist doing it for learners — the hands have to learn it.
  • Stretch the battery band first. Pinch the yellow rubber band with a thumb and middle finger and stretch it wide before sliding it onto the battery. Without the stretch, the wires slip out as you try to seat them. It may take a couple of tries either way — that is normal.
  • Wiggle to fix friction. If the axle will not spin, the bearing is too tight. Wiggle the axle around inside the bearing to stretch it a little. This is a troubleshooting move, not a build move, but it saves stuck vehicles in seconds.
  • Nudge the foam bearing to fix gear mesh. If the motor spins but the wheels do not, push the foam bearing on the base up or down just enough to shift the axle angle. That tiny nudge is usually all it takes to make the two gears catch.
  • Reserve spare parts for the Iterate step. The basic build only uses one of the two cardboard bars that the platform splits into, and only two of the four plastic connectors. Have learners set the extra bar and the extra two connectors aside at the start — they become the raw materials for redesigning a longer, wider, or multi-axle vehicle during Step 9.
  • Detach a wire for storage. When storing incomplete projects in the reclosable bag, detach at least one wire from the battery. Otherwise the circuit stays closed and the battery drains while no one is looking.
  • Use the slide deck as your how-to first. Build an Electric Vehicle of your own using the slide deck before the lesson. It is the fastest way to feel where the tricky moments are so you can coach through them with confidence.
  • Go slower for Grades 3 and 4. The playbook calls out that younger learners benefit from many check-in moments. Stop after each step and let everyone catch up before moving on — the gear-wheel and battery-band steps especially need patience.

Step-by-Step Guide

Step 1: Build the Base

Question: What do you notice when you look at the cardboard piece? Can you find the square part where the motor will attach?

  • Have learners carefully break the cardboard platform apart along the perforated lines. The piece splits into a square section (the base) and a long bar (you will save the bar for the second axle in Step 8).
  • Focus on the square part — this is where the motor will go. Point out the small slot in the middle of the square.
  • Save the tab in the middle of the square. It looks like a small piece of scrap, but it is critical — it slides in later to keep the motor from falling out.
  • Set the long bar aside for now. Learners will use it in Step 8 when they build the second axle.
  • Remind learners to take their time breaking the cardboard — torn edges make the motor clip harder to snap in later.

Step 2: Attach the Motor

Question: Your motor is already clipped to a plastic holder — how do you think it snaps into the base?

  • The motor comes already attached to its motor clip. Learners just need to firmly push the clip down into the square cut-out in the base. They should feel and hear it snap into place.
  • Now take the small tab that was saved from Step 1 and slide it into the slot next to the motor clip. This prevents the motor from falling out when the vehicle is in motion.
  • Check: gently tug on the motor clip — it should stay firmly in the base. If it pops out, the tab is not seated correctly.
  • The red and black wires should hang loose off the motor for now — they will connect to the battery in Step 5.

Step 3: Connect the Gear Wheel to the Axle

Question: The gear wheel has ridges on it — why do you think it needs to line up with the gear on the motor?

  • Have learners remove all of the foam pieces from the die-cut sheet. Remind them not to lose any — every piece has a job, and the leftovers come in handy during the Iterate step.
  • For Step 3 they need: the small foam wheel, three bushings, one bearing, one wooden axle, and the plastic gear wheel.
  • Push the gear wheel onto the end of the axle — push AND twist while holding the axle near the end. This is the trickiest move in the build. It helps to do it at an angle.
  • If a learner struggles, have them hold the axle firmly, push the gear down slowly, and add a quarter-twist at the same time. Avoid doing it for them — the twist is a skill that pays off.

Step 4: Assemble the First Axle

Question: What does the foam bearing do, and why does it need to line up with the hole on the motor clip?

  • Press one bearing into the base on the opposite side of the motor clip hole. Gently push it into place.
  • Slide the axle (gear end first) through the motor clip hole, then add two bushings, then push through the bearing. Keep pushing until the gear wheel on the axle lines up perfectly with the gear on the motor. The two gears should mesh so their teeth overlap.
  • Adjust the bushings on either side of the gear wheel — one pressed up against the motor clip, another pressed against the bearing. This locks the axle in place so it cannot slide side-to-side.
  • Finish the axle by adding a second foam wheel and one more bushing for support on the other end.
  • Check the mesh: spin the gear wheel on the axle by hand — you should hear and feel it clicking against the motor gear.

Step 5: Connect the Battery

Question: A circuit needs electricity to flow in a loop — how do you think the battery and the wires work together to make that loop?

  • Grab the yellow rubber battery band and the AA battery. The motor's red and black wires need to press firmly against the battery's positive and negative ends, and the band holds them there.
  • Stretch the band first. Pinch it with a thumb and middle finger to stretch it wide before sliding it over the battery — this makes a tricky process much easier. It may take a couple of tries.
  • Slide one wire end under the band so it presses against the positive (+) end of the battery, then slide the other wire end under the band against the negative (-) end.
  • The motor should start spinning immediately — that means the circuit is closed and electricity is flowing from the battery through the wires, through the motor, and back. Celebrate the first spin!
  • If nothing happens, check that both wire ends are making firm contact with the battery terminals under the band. Loose wires are the most common issue.

Step 6: Test and Swap Polarity

Question: The vehicle is rolling — but is it going the direction you expected? What would happen if you switched the wires?

  • Set the vehicle down on a flat surface and watch which way it rolls. Depending on which wire is on which battery terminal, it will roll either forward or backward.
  • When it rolls forward, the motor is applying a push force. When it rolls backward, the motor is applying a pull force.
  • Now for the big reveal: swap the two wires under the battery band so the red wire is where the black wire used to be, and vice versa. Ask learners to predict what will happen before they test.
  • Watch what happens: the motor spins in the opposite direction, and the vehicle now rolls the other way. This is polarity in action. Switching the wires reversed the flow of electricity around the circuit, which reversed the direction of the motor.
  • Invite learners to talk about it in the language of circuits — the electricity flowed one way before and now flows the other way.

Step 7: Troubleshoot

Question: What could be stopping your vehicle from rolling? Where in the circuit or the gears do you think the problem might be?

  • If the axle will not spin: wiggle the axle around to stretch the foam bearing. This eliminates some of the friction and gives the axle room to move freely.
  • If the gear wheel and the motor gear are not meshing: push the foam bearing on the base to fix the angle of the axle. Nudging the bearing up or down shifts the axle just enough for the two gears to catch.
  • If the motor is not spinning at all: check the battery connection. Both wires must be pressed firmly against the battery terminals under the rubber band. Loose wires are the number-one cause.
  • Ask questions before fixing anything: "What do you notice when the gear spins?" or "Where is the electricity stopping?" Let learners discover the problem themselves — the troubleshooting is the learning.

Step 8: Build the Second Axle and Attach It

Question: How will you keep the second axle level with the first one? What are the plastic connectors for?

  • Grab the long cardboard bar that was saved from Step 1. For the basic build, only one of the bars is needed — the other can be set aside or used during the Iterate step.
  • Insert bearings into each of the holes on the bar. Make sure both bearings are aligned with each other so the axle can slide straight through.
  • Slide the second wooden axle through both bearings. Add bushings on either side for support, but leave a small space so the axle still spins freely. Finish by adding wheels to both ends.
  • Now attach the second axle bar to the base using plastic connectors (pinchers). Each Spark includes four connectors, but the basic build only needs two. Slide the connector pinchers into the base wherever you want the second axle to sit.
  • Set the vehicle down and give it a test drive. Both axles should now roll smoothly across a flat surface.

Step 9: Iterate!

Question: Now that your vehicle works, what could you change to make it one of a kind? How can you use the paper tubes, straws, or leftover foam pieces?

  • This is where every Electric Vehicle should start to look different. Challenge learners to deconstruct the basic build and rebuild using paper tubes, straws, and any leftover foam from the die-cut sheet.
  • Remind learners that it is okay to fail and try again — that is the whole point of iteration.
  • See the Extension Activities field below for specific design challenges learners can take on during this step, including smallest-vehicle, three-wheel, circle-driving, and vehicle-combining challenges.
Post-Activity Questions
3rd - 5th Grade
  1. What happened when you connected the wires to the battery? Where did the electricity go?
  2. What did you have to do when the gear wheel on your axle was not lining up with the motor gear?
  3. When you swapped the two wires under the battery band, what changed about the way your vehicle moved, and why?
6th - 8th Grade
  1. Trace the path of the electricity in your finished vehicle. Where does it start, what does it flow through, and what makes it do work?
  2. How does swapping the wires at the battery change the polarity of the circuit, and how does that show up in the motion of the motor?
  3. If you redesigned your Electric Vehicle during the Iterate step, what design choice made the biggest difference in how it moved — and why do you think that is?

Standards & Goals

Common Core ELA Standards

K-2
3-5
6-8

RI.K-2.7 – Use illustrations and words in a text to describe key ideas: Example: Learners use the printed visual guide sheet and the slide deck to identify the foam components in their Electric Vehicles kit, matching each picture to the real piece — finding the small wheel, the bearings, the bushings, and the gear wheel before they start building.

SL.K-2.1 – Participate in collaborative conversations: Example: Learners tell a partner what happens when they connect the two wires to the battery, using words like "motor," "spin," and "wire" to describe the first time their circuit closes and the motor starts turning.

RI.3-5.7 – Interpret information presented visually: Example: Learners read the slide deck and the printed visual guide to identify which side of the platform the plastic wheel connects to, interpreting the diagrams and photos to place the bearings, gears, and axle in the correct positions before the motor is powered.

SL.3-5.1 – Engage effectively in collaborative discussions: Example: Learners answer prompts like "what do you think each component is called?" with their neighbors, discussing the difference between bearings and bushings and agreeing on a troubleshooting strategy when a classmate's gear wheel will not mesh with the motor gear.

RST.6-8.3 – Follow a multistep procedure when carrying out experiments: Example: Learners follow the nine-step Electric Vehicles build sequence precisely, recognizing that the order matters — the gear wheel must be pressed onto the axle before the axle is inserted into the motor clip, and the battery must be connected last so the motor only starts spinning at the intended moment.

SL.6-8.1 – Engage in collaborative discussions with diverse partners: Example: Learners debate what changed when the wires were swapped on the battery during the polarity test, comparing observations with classmates and building a shared explanation of how the direction of current flow controls the direction of the motor.

Common Core Math Standards

K-2
3-5
6-8

K.MD.A.1 – Describe measurable attributes of objects: Example: Learners compare the sizes of the foam wheels, describing which wheel is larger and which is smaller when deciding which wheel to press onto the axle first.

K.G.A.2 – Correctly name shapes regardless of orientation or size: Example: Learners identify the circular wheel, the rectangular foam bearing, and the round bushings from the die-cut sheet, naming each shape aloud before placing it on the axle or base.

3.G.A.1 – Reason with shapes and their attributes: Example: Learners pick the correct foam part by shape and size from the die-cut sheet — small circular wheel, large circular wheel, rectangular bearing with circular hole — following the visual guide to put the correct piece in the correct spot on the platform.

4.G.A.1 – Draw and identify lines and angles, and classify shapes: Example: Learners identify the three-sided rectangular tab that must sit on the correct side of the platform and classify the foam wheels and bushings by their circular or rectangular cross-sections as they reason about which piece fits where on the first axle assembly.

6.RP.A.1 – Understand ratio concepts and use ratio reasoning: Example: Learners observe the gear-ratio relationship between the motor gear and the axle gear wheel — noting how many times the motor gear must spin before the larger axle gear completes one full rotation — and discuss how changing the gear ratio would change the vehicle's speed.

7.RP.A.2 – Recognize and represent proportional relationships: Example: Learners test the relationship between battery voltage and motor output by racing classmates with fresh versus partly-drained batteries, representing the proportional (and eventually non-proportional) relationship between power input and vehicle speed.

Next Generation Science Standards (NGSS)

K-2
3-5
6-8

K-PS2-1 – Motion and Stability: Forces and Interactions: Example: Learners observe the push force when the vehicle rolls forward and the pull force when the wires are swapped, discovering that pushes and pulls from the motor can change the motion of their Electric Vehicle across the table.

K-2-ETS1-1 – Engineering Design: Ask questions, make observations: Example: Learners observe a vehicle that is stuck and compare it to a classmate's that is rolling, asking questions about what is different — a loose wire, a misaligned gear, or a tight bearing — and defining the problem to solve before changing anything.

4-PS3-2 – Energy Transfer: Make observations about energy transfer: Example: Learners observe how energy from the AA battery transfers through the wires into the DC motor and then through the gear train into the wheels, tracing the path of electric current from source to work output and confirming the transfer by disconnecting the battery and watching the motor stop.

3-5-ETS1-3 – Plan and carry out fair tests to identify failure points: Example: Learners systematically troubleshoot a stuck Electric Vehicle by isolating one variable at a time — wiggle the axle to test friction, nudge the foam bearing to test gear alignment, check the battery band to test circuit closure — finding the exact failure point instead of guessing.

MS-PS3-5 – Construct an explanation of energy transfer: Example: Learners explain how the chemical energy in the AA battery is converted into electrical energy in the wires, then into mechanical energy in the motor, and finally into kinetic energy in the rolling vehicle — identifying each transformation along the way and predicting what happens to each form of energy when the circuit is broken.

MS-ETS1-3 – Analyze data to compare design solutions: Example: Learners compare their Iterate-step redesigns against classmates' in a timed race, analyzing which design choices (wheel size, weight distribution, number of wheels, body shape) produced the fastest or most reliable vehicle and using that data to refine a second-round design.

Troubleshooting & Pro Tips

Motor Will Not Spin at All

The circuit is open somewhere. Check that both wire ends are pressed firmly against the battery terminals under the yellow rubber band. Loose wires are the number-one cause. Also make sure the battery is in the right orientation and that the band is not pinching a wire away from the terminal.

Motor Spins but Wheels Do Not Turn

The gear wheel on the axle is not meshing with the motor gear. Push the foam bearing on the base up or down to shift the axle angle until the two gear teeth catch. You should hear and feel the click when they mesh.

Axle Will Not Spin Freely

The bearing is too tight and creating friction on the axle. Wiggle the axle around inside the bearing to stretch it a little. Also check that the bushings on either side of the gear are not pressed so hard they are squeezing the axle to a stop.

Battery Band Keeps Slipping Off

The band is not stretched enough before being seated. Pinch it with a thumb and middle finger to stretch it wide, slide it over the battery, and only then tuck the wires underneath. It may take two or three tries — that is normal.

Vehicle Rolls Backward Instead of Forward

That is polarity. The wires are on the opposite terminals from what you expected. Swap the two wires under the battery band and the vehicle will reverse direction. Use this as a teaching moment about how polarity controls motor direction.

Motor Falls Out of the Base

The small cardboard tab from Step 1 is missing or not seated. Insert the tab into the slot next to the motor clip — it is what holds the motor in place once it is pushed in.

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