Eyelusions

What are Eyelusions?

Build a motorized thaumatrope — a spinning disc that merges two drawings into one optical illusion. Learners design image pairs, assemble a battery-powered spinner, and discover firsthand how their brain can be tricked into seeing something that isn’t actually there.

Time Needed:
20–60 minutes. Can be set up as a 20-minute event station or extended to 60 minutes for a full lesson.
Grade Level:
K and up
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Eyelusions Practice Sheet

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Overview

Eyelusions delivers a complete motorized thaumatrope that learners assemble and design from scratch. Using foam components, a DC motor, and an AA battery, they build a working spinner, then draw split images across two stickers — choosing their own challenge level from the “spice scale”: top-and-bottom (mild), left-and-right (medium), or opposite-corners (spiciest). When the tube spins and the wires touch the battery, two pictures become one.

The build moves through nine steps: exploring kit components, assembling the foam base, installing the motor, testing the circuit, planning a design on the practice sheet, drawing on stickers, attaching stickers to the tube, connecting the tube to the motor, and spinning to see the illusion come to life — with an Iterate step inviting new designs. A printable practice/design sheet lets learners experiment freely with image-splitting ideas before committing to stickers, making mistakes a built-in part of the process.

Once their first illusion works, learners have two more sets of stickers ready to go — plus the option to use sticky notes or cut-out practice-sheet drawings for even bigger, more inventive illusions. A standout extension is the collaborative challenge: one learner draws the top half of an image while a partner draws the bottom half without seeing each other’s work, producing results that are often hilarious and always unique.

Materials

Each learner recieves
  • A set of three foam components (two rectangular bases and a motor holder strip)
  • One AA battery
  • A DC motor with connector and wires
  • A sturdy paper tube
  • Three sets of stickers with dotted guidelines (top/bottom, left/right, and diagonal markings) — six stickers total
  • Instruction sheet
  • Reclosable bag for re-using and storing
What you need to provide

Educators must provide: pencils (strongly encouraged for the planning and design steps), markers or crayons (water-based markers recommended — darker images are more visible when spinning), and scissors (needed for trimming a mushed tube end and for cutting practice-sheet drawings into extended-design pieces).

Optional resources
  • Printed practice/design sheet for each learner (available as a free printable) — lets learners sketch and experiment before drawing on stickers
  • Sticky notes — usable as replacement discs once circle stickers run out
  • Tape — for attaching cut-out practice-sheet drawings to the tube as larger design panels
  • Scrap paper — for extra design sketches and backup image pairs

Key Challenges

  1. Splitting an image across two stickers. Designing a pair of half-images that actually blend into something recognizable when spinning takes planning — learners must think in reverse and resist the urge to draw complete pictures on each sticker.
  2. Aligning stickers correctly on the tube. Orientation matters: top must stay at top and bottom at bottom on both sides of the tube, or the illusion breaks. A single misaligned sticker produces a scrambled result, teaching learners to slow down and check before pressing down.
  3. Making reliable wire-to-battery contact. The motor only runs when both wire ends touch the metal terminals. Bent wire tips or a shifted battery can break the circuit — learners must diagnose what’s wrong and adjust, often stretching the foam gently to restore contact.
  4. Choosing and executing a spice-level design. The three image-splitting techniques (top/bottom, left/right, opposite corners) increase in difficulty. Attempting a spicier split rewards learners who plan carefully on the practice sheet, while mild designs give everyone a working starting point.

Learner Goals

MUST
  • Assemble the foam base, install the motor, and complete a working motorized spinner
  • Test the motor circuit by touching both wire ends to the battery terminals
  • Design and draw at least one split-image pair across two stickers using a dotted guideline
  • Attach stickers to the tube with correct orientation and connect the tube to the motor to produce a visible optical illusion
SHOULD
  • Use the practice/design sheet to plan their image pair before drawing on stickers, applying at least one round of revision
  • Attempt a second sticker set with a different spice-level technique (for example, moving from top-and-bottom to left-and-right) and compare how the illusion changes
  • Explain in their own words why the two images appear to blend — referencing the idea that the brain fills in gaps when images change faster than it can process them
COULD
  • Complete the collaborative challenge: design one half of an image independently while a partner designs the other half without seeing each other’s work, then combine and spin to reveal the result
  • Create a successful illusion using the spiciest technique — opposite-corner splitting — demonstrating careful pre-planning on the practice sheet
  • Replace stickers with sticky notes or cut-out practice-sheet drawings to produce a larger, more complex illusion and iterate on the design across multiple attempts

Extension Activities

  • Collaborative Half-Image Challenge: Pair learners up and have one person draw the top half of an image on one sticker while their partner draws the bottom half on a separate sticker — without showing each other what they’ve made. When the images spin together, the unexpected combinations are often hilarious and spark great conversation about design choices. This is a natural way to get learners collaborating and laughing together.
  • Sticky Note Supersized Illusions: Once circle stickers are used up, challenge learners to create larger image pairs using sticky notes or cut-out drawings from the practice sheet. Bigger images with more detail reveal new challenges around alignment and proportion — and the results are more dramatic when they spin.
  • Spice Scale Showdown: Encourage learners who have completed the mild level to attempt the medium or spiciest technique. The diagonal/opposite-corners split is the hardest to plan and the most satisfying when it works. Invite successful “spiciest” builders to explain their planning process to the group.
  • New Sticker Design Exploration: With two additional sets of stickers remaining, challenge learners to use the slide deck’s prompt pairs — bird + nest, cat + hat, alien + truck — or invent their own image combination. Each new pair is a new experiment in how the brain blends two things into one.

Before You Start

Watch Our Educator Guide!
Pre-Activity Questions
K - 2nd Grade
  1. Have you ever seen a picture that tricked your eyes? What did it look like?
  2. If you spun two pictures around really, really fast, what do you think your eyes would see?
3rd - 5th Grade
  1. How do you think your brain figures out what you’re looking at when things are moving very quickly?
  2. If you drew two halves of a picture on separate circles and spun them together, what would need to be true about each half for the two images to blend into one?
6th - 8th Grade
  1. What do you already know about how the eye processes motion — why does a flipbook animation look like it’s moving even though each page is still?
  2. If you were designing an optical illusion that combined two images, what variables would you consider — composition, color, contrast — and why might each one matter?
Pro Tips
  • Use pencil first, always. Encourage learners to plan their image pairs on the practice sheet before committing anything to a sticker. The planning sheet is where mistakes are welcome — this is where the real design thinking happens. (Source: transcript, slide deck)
  • Start mild, work up the spice scale. Introduce the three difficulty levels — top/bottom (mild), left/right (medium), and diagonal/opposite corners (spiciest) — before learners begin. Let them attempt the level they want, and affirm that trying a spicier technique is always worth the challenge even if the first attempt doesn’t work perfectly. (Source: transcript)
  • The darker, the better. Once learners are happy with a pencil sketch, prompt them to trace over it boldly with markers or crayons. The darker and more defined the image, the more visible and striking it will be when the disc spins. (Source: transcript)
  • Alignment is everything. When attaching stickers to the tube, coach learners to make sure “top stays at top and bottom stays at bottom” on both sides. A misaligned sticker pair won’t blend the way the brain expects. (Source: transcript)
  • Celebrate the wigglers. If a tube is slightly off-center, the whole base will vibrate and slowly wiggle across the table. Frame this as a feature: “It’s alive!” Learners love the movement, and it usually doesn’t affect the optical illusion. Reserve troubleshooting for tubes that are truly unstable. (Source: transcript)
  • Encourage peer help before educator intervention. When a learner gets stuck, invite them to seek out a classmate who has a working example rather than stepping in immediately. This builds collaborative problem-solving and lets learners take ownership of their breakthroughs. (Source: transcript)
  • Stickers run out — and that’s a feature. When learners exhaust their circle stickers, sticky notes and cut-out drawings from the practice sheet become the next canvas. Bigger images, more unusual combinations — the constraint becomes creative fuel. Have sticky notes and tape ready before the session starts. (Source: transcript, playbook)
  • Use the slide deck to prime the big idea. Open with the slide deck question — “Is it possible to see something that isn’t there?” — before any building begins. This primes learners to approach the activity as a science investigation, not just a craft. The deck also walks through each build step visually, which helps with vocabulary and peer-to-peer instruction. (Source: slide deck, coach guide)

Step-by-Step Guide

Step 1: Explore Your Materials

Question: What’s in your kit, and what do you think each piece does?

  • Give learners a moment to examine all kit components before building: two rectangular foam bases, a long foam motor holder strip, one AA battery, a DC motor with wires and a connector cap, a paper tube, three sets of stickers with dotted guidelines, and an instruction sheet.
  • Ask learners to predict which pieces hold other pieces, which pieces move, and which pieces create the illusion.
  • Confirm that scissors and drawing tools (pencils, markers, or crayons) are within reach — learners will need them for the design steps.
  • Pro tip: Set out sticky notes or scrap paper now as a backup for when stickers run out. Water-based markers work best on the sticker surface.

Step 2: Assemble the Foam Base

Question: How do the foam pieces fit together to hold the battery in place?

  • Have learners start with the two rectangular foam bases. Stack them so their slots line up — the alignment is important for the battery fit.
  • The battery fits into the larger opening in the stacked bases. Press it down through both layers — this is what holds the two bases together.
  • Encourage learners to check that the battery is seated firmly before moving on. It should feel snug, not wobbly.

Step 3: Install and Attach the Motor

Question: How does the foam hold the motor without any glue or screws?

  • Have learners insert the motor through the opening in the long foam motor holder strip. The foam grips the motor body to hold it in place — friction is the fastener.
  • Orient the motor with wires facing down and the motor shaft facing up, then press the ends of the motor holder strip all the way into the slots on either side of the battery.
  • Troubleshooting: If the metal wire ends have bent and are hard to seat alongside the battery, lift the battery, hold the wire in position, then press both the battery and the wire down into the foam together.

Step 4: Test Your Motor

Question: What makes the motor spin — and does it matter which wire touches which end?

  • Have learners touch the metal tip of each wire to one terminal of the battery — one wire per end. Once both wires make contact with metal, the motor will spin.
  • If the motor doesn’t spin immediately, gently stretch the foam so the wire tips press fully against the battery terminals.
  • Invite learners to swap the wires and observe what changes: reversing the wires reverses the direction the motor turns — the speed stays the same. Both directions work for the illusion.
  • Troubleshooting: If the motor still won’t spin after confirming wiring, check that the motor body hasn’t slipped out of position in the foam holder.

Step 5: Plan Your Design

Question: How do you split one image into two pieces that will blend back together when spinning?

  • Distribute the practice/design sheet and have learners sketch ideas in pencil before touching their stickers. Mistakes are welcome here — that’s exactly what the practice sheet is for.
  • Introduce the three ways to split an image using the dotted guidelines on the stickers:
    • Top and bottom (mild): Designs appear above the horizontal guideline on one sticker and below the line on the other.
    • Left and right (medium): Uses the vertical guideline — one image on the left, the matching half on the right.
    • Opposite corners (spiciest): Top left paired with bottom right, or top right paired with bottom left — a diagonal split.
  • Encourage learners to try a spicier technique even if they’re unsure. Attempting a harder split is always worth it — and other learners with working examples are a great resource if someone gets stuck.
  • Classic starting point: draw just the eyes of a face on one sticker, just the mouth on the other. Have learners practice this pair before inventing their own.

Step 6: Design Your Stickers

Question: How do you get your planned image from the practice sheet onto your stickers?

  • Once learners are happy with a design on the practice sheet, have them transfer it to their stickers — start in pencil, then trace over with markers or crayons.
  • Remind learners: the darker and bolder the image, the more visible it will be when the disc spins. Light, thin lines can disappear at speed.
  • Learners have three sets of stickers — encourage them to use the first set to experiment and the second or third for a refined design.
  • Pro tip: When stickers run out, sticky notes or drawings cut from the practice sheet can be taped to the tube to create bigger, more unique illusions.

Step 7: Attach Stickers to Tube

Question: Does it matter where on the tube each sticker goes?

  • Have learners attach the first sticker to one side of the paper tube, then flip the tube over and attach the second sticker to the back.
  • Alignment matters: the top of each sticker should stay at the top on both sides. If the stickers are rotated relative to each other, the illusion won’t work.
  • Troubleshooting: If one end of the tube is mushed or bent, trim it straight with scissors before attaching stickers — a clean, flat edge spins more smoothly.

Step 8: Attach Tube to Motor and Spin

Question: What happens when the two images start moving faster than your eyes can follow?

  • Have learners hold the motor body firmly and press the tube down onto the connector cap until it sits straight and secure.
  • Troubleshooting: If the connector cap comes loose from the motor shaft, wrap a tiny piece of tape around the shaft and press the cap back on — the tape adds friction to keep it in place.
  • Now touch the wires to the battery terminals and watch two images become one. Invite learners to observe and describe what they see.
  • Pro tip: A little wobble and vibration is normal — and learners love it when their machines slowly wiggle across the table. If the tube is very off-center, remove it and reseat it straighter on the connector.

Step 9: Iterate!

Question: Now that you know how it works, what would you do differently — or what new illusion can you create?

  • Eyelusions is designed to be used over and over — learners can swap in new sticker combinations as many times as they like.
  • See the Extension Activities for the collaborative challenge (two learners design matching halves without seeing each other’s work) and other ways to push the illusion further.
  • Encourage learners to try a spicier split technique if they started with mild, or to invent a completely new image pair using what they’ve learned about how thaumatropes work.
Post-Activity Questions
K - 2nd Grade
  1. What did you see when your disc started spinning? Was it what you expected?
  2. If you could draw any two things to blend together, what would you pick and why?
3rd - 5th Grade
  1. What happened in your brain when the disc spun — why do you think you saw one image instead of two separate ones?
  2. Which spice level did you try, and how did the way you split your image affect what you saw when it spun?
6th - 8th Grade
  1. The phi phenomenon describes how the brain fills in gaps between fast-moving images to create the perception of a single continuous picture — how did you see evidence of that in your thaumatrope today?
  2. What would you change about your image pair — the composition, the contrast, or the spice-scale technique — if you were going to make another one, and what’s your reasoning?

Standards & Goals

Common Core ELA Standards

K-2
3-5
6-8

RI.K-2.7 – Use illustrations and details to describe key ideas: Learners use the practice sheet and spice scale illustrations to plan their image pairs, connecting visual diagrams of the three splitting strategies (top/bottom, left/right, opposite corners) to the concept of how two halves combine into a single blended picture.

SL.K-2.1 – Participate in collaborative conversations: Learners discuss their sticker design choices with peers during the planning and iteration stages, sharing which spice-scale technique they chose and why, and asking for help from classmates who have a working illusion when their own design doesn’t blend correctly.

RI.3-5.3 – Explain relationships between events or concepts: Learners explain the cause-and-effect relationship between spinning speed and image blending, articulating how the motor’s rotational rate determines whether the brain perceives two separate sticker drawings or one fused optical illusion.

W.3-5.3 – Write narratives to develop experiences: Learners connect the thaumatrope’s history to modern animation and film, writing or discussing the narrative arc from early optical toys (thaumatropes) through cartoons to movies, using the “wonder turner” etymology as a story anchor for how persistence of vision shaped visual storytelling.

RST.6-8.3 – Follow precisely a multistep procedure: Learners execute the nine-step build sequence — from stacking and slotting foam bases through motor installation, wire testing, sticker alignment, and tube attachment — applying precise procedural reading to ensure the connector sits straight and sticker orientation is maintained on both sides of the tube.

SL.6-8.1 – Engage in collaborative discussion: Learners evaluate competing design technique choices with peers, discussing the tradeoffs between mild (top/bottom), medium (left/right), and spiciest (opposite corners) splitting strategies, and citing evidence from their own spinning results to support which approach produced the clearest illusion.

Common Core Math Standards

K-2
3-5
6-8

K.G.A.1 – Describe positions and shapes in the environment: Learners identify and describe the circular sticker shape and the relative positions of image halves — above/below the horizontal guideline, left/right of the vertical guideline, or in opposite corners — as they plan their designs on the practice sheet using spatial vocabulary.

K.MD.A.1 – Describe measurable attributes of objects: Learners observe and compare measurable attributes of the spinning disc, noticing differences in how clearly images blend at different spin speeds and discussing which wire-to-battery contact pressure produces steady rotation versus intermittent spinning during the motor test step.

3.G.A.1 – Understand that shapes in different categories may share attributes: Learners analyze the circular sticker as a geometric shape divided by horizontal, vertical, and diagonal guidelines — partitioning the circle into two equal regions and comparing how each splitting strategy (top/bottom, left/right, opposite corners) creates symmetrical halves that serve as mirror-image designs when the thaumatrope spins.

4.OA.C.5 – Generate and analyze a pattern: Learners identify the repeating spatial pattern in each sticker splitting strategy — recognizing that top/bottom, left/right, and diagonal splits are systematic geometric transformations of the same circle — and predict how changing the division axis changes which part of the image appears on each sticker.

6.RP.A.1 – Understand the concept of a ratio: Learners reason about the ratio of spin speed to the persistence-of-vision threshold, understanding that the phi phenomenon only produces a blended image when rotation exceeds approximately 10–12 frames per second, and connecting this ratio to why the DC motor’s fixed speed makes the illusion reliable while hand-spinning is inconsistent.

6.G.A.1 – Find area and solve problems involving geometric figures: Learners apply geometric reasoning to the circular sticker divided by the dotted guidelines, analyzing how each splitting strategy partitions the circle’s area into two complementary regions — halves for top/bottom and left/right splits, and diagonal quadrant pairs for the opposite-corners (spiciest) technique.

Next Generation Science Standards (NGSS)

K-2
3-5
6-8

K-PS2-1 – Plan and conduct an investigation to compare forces: Learners test the motor by pressing wire ends to battery terminals, directly investigating how electrical contact produces rotational force and observing that reversing the wire connections changes the direction the motor spins, connecting push/pull force concepts to the spinning motion that drives the illusion.

K-2-ETS1-2 – Develop a simple sketch or model to illustrate a solution: Learners use the practice sheet to sketch and refine image pair designs before committing to stickers, treating the planning sheet as an iterative model where mistakes are welcome and multiple approaches (mild, medium, spiciest) can be tested before selecting a final design to transfer.

3-PS2-1 – Investigate the effects of balanced and unbalanced forces on motion: Learners observe how the centered versus off-center placement of the paper tube on the motor connector affects rotational motion, discovering that a misaligned tube causes the entire base to vibrate and wobble across the table, directly demonstrating how unbalanced forces disrupt steady rotation.

3-5-ETS1-3 – Plan and carry out fair tests to identify failure points: Learners iterate through multiple sticker design attempts using the three spice-scale splitting techniques, testing each design by spinning and observing whether the illusion blends correctly, identifying which approach worked and why — and using sticky notes or cut practice sheet drawings when stickers run out to extend their testing.

MS-LS1-8 – Gather and synthesize information that sensory receptors respond to stimuli by sending messages to the brain: Learners investigate how the visual system’s sensory receptors transmit signals to the brain faster than the brain can resolve two distinct images when the thaumatrope spins, modeling the phi phenomenon as the brain’s integration of rapidly alternating visual stimuli into a single perceived image — directly connecting the retina’s response to spinning stimuli to the neural processing that produces the optical illusion.

MS-ETS1-2 – Evaluate competing design solutions using criteria and constraints: Learners compare the three sticker splitting strategies on the spice scale, evaluating each against the criteria of image clarity and the constraint of the circular sticker boundary, using evidence from spinning results to determine which technique (top/bottom, left/right, or opposite corners) best meets the goal of producing a convincing blended illusion.

Troubleshooting & Pro Tips

Bent wire ends

The metal ends of the motor wires can bend, making it hard to insert them alongside the battery. If this happens, lift the battery up slightly, hold the wire in position against the terminal, and press both the wire and battery down into the foam together.

Off-center tube causing vibration

A small amount of wobble is normal and learners often enjoy watching their machine slowly wiggle across the table. If the vibration is severe, check that the tube is seated straight on the motor connector. Press the connector fully down until it sits secure and centered.

Mushed or bent tube end

If the end of the paper tube is bent or crushed, it won’t sit squarely on the motor connector. Trim the end straight with scissors to restore a clean, flat edge before reattaching.

Loose connector cap

If the plastic connector cap comes loose from the motor shaft, place a tiny piece of tape on the motor shaft first, then press the cap back on firmly. The tape adds friction and holds the cap in place during spinning.

Motor won’t spin despite correct wiring

If the wires are touching the correct battery terminals but the motor isn’t running, check whether the motor has shifted out of its holder. The foam strip grips the motor body — if the motor has slid, reseat it so it fits snugly, then retest.

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