In this activity about light and perception, learners discover how a flash of light can create a lingering image called an "afterimage" on the retina of the eye. Learners will be surprised when they continue to see an image of a bright object after staring at it and looking away. Use this activity to introduce learners to principles of optics and perception as well as to explain why the full moon often appears larger when it is on the horizon than when it is overhead. This lesson guide also includes a few extensions like how to take "afterimage photographs."

In this optics activity, learners discover that when they rotate a special black and white pattern called a Benham's Disk, it produces the illusion of colored rings. Learners experiment with the speed of rotation and direction of rotation to observe varying patterns. Use this activity to explain to learners how our eyes detect color and how different color receptors in the eye respond at different rates.

Stare at one color—but see another. You see color when receptor cells (called cones) in your eye’s retina are stimulated by light. There are three types of cones, and each is sensitive to a particular color range. If one or more of the three types of cones adapts to a stimulus because of long exposure, it responds less strongly than it normally would.

Students apply what they know about light polarization and attenuation (learned in the associated lesson) to design, build, test, refine and then advertise their prototypes for more effective sunglasses. Presented as a hypothetical design scenario, students act as engineers who are challenged to create improved sunglasses that reduce glare and lower light intensity while increasing eye protection from UVA and UVB radiation compared to an existing model of sunglasses—and make them as inexpensive as possible. They use a light meter to measure and compare light intensities through the commercial sunglasses and their prototype lenses. They consider the project requirements and constraints in their designs. They brainstorm and evaluate possible design ideas. They keep track of materials costs. They create and present advertisements to the class that promote the sunglasses benefits, using collected data to justify their claims. A grading rubric and reflection handout are provided.

This online exhibit is a visual illusion in which a fuzzy blue dot disappears into a green background. The illusion is created by the tiny jittering movements that your eyes are continually making. Take your investigation further by making your own hands-on fading dot illusion - instructions are at the Exploratorium Snack website (see related link).

Poster showing a pair of staring eyes on a black background. Title transcribed from item.

Acting as if they are biomedical engineers, students design and print 3D prototypes of pressure sensors that measure the pressure of the eyes of people diagnosed with glaucoma. After completing the tasks within the associated lesson, students conduct research on pressure gauges, apply their understanding of radio-frequency identification (RFID) technology and its components, iterate their designs to make improvements, and use 3D software to design and print 3D prototypes. After successful 3D printing, teams present their models to their peers. If a 3D printer is not available, use alternate fabrication materials such as modeling clay, or end the activity once the designs are complete.

In this activity, students will play 'Guess Who?' in teams or individuals. They will practice asking about the appearances of people politely and try to figure out who the unknown person is.

Students design and build prototypes for protective eyewear. They choose different activities or sports that require protective eyewear and design a device for that particular use. Students learn about the many ways in which the eyes can be damaged and how engineers incorporate different features and materials into eyewear designs to best protect the eyes.

In this activity, learners explore their eye pupils and how they change. Learners use a magnifying glass, mirror, and flashlight to observe how their pupil changes size in response to changes in lighting. Learners also experiment to determine how light shining in one eye affects the size of the pupil in their other eye. This resource guide includes background information about pupils and why they change as well as information related to emotional stimuli, involuntary reflexes, and photography.

Students practice human-centered design by imagining, designing and prototyping a product to improve classroom accessibility for the visually impaired. To begin, they wear low-vision simulation goggles (or blindfolds) and walk with canes to navigate through a classroom in order to experience what it feels like to be visually impaired. Student teams follow the steps of the engineering design process to formulate their ideas, draw them by hand and using free, online Tinkercad software, and then 3D-print (or construct with foam core board and hot glue) a 1:20-scale model of the classroom that includes the product idea and selected furniture items. Teams use a morphological chart and an evaluation matrix to quantitatively compare and evaluate possible design solutions, narrowing their ideas into one final solution to pursue. To conclude, teams make posters that summarize their projects.

By examining the progress of a genetic eye disease, students learn about eyes, genetic disorders, and neurons in this case designed for clickers and large lecture sections.

In this quick optics activity, learners use a dim point of light (a disassembled Mini MagLite and dowel set-up) to cast a shadow of the blood supply in their retina onto the retina itself. This allows learners to see the blood supply of their retina and even their blind spot. Learners are encouraged to wear eye protection.

Closing one eye eliminates one of the clues that your brain uses to judge depth. Trying to perform a simple task with one eye closed demonstrates how much you rely on your depth perception. In this activity, learners compare their ability to perform simple tasks with one eye versus with two eyes.

In this activity, learners overlap the three primary colors to see how all other colors are made. This activity also explains how color can be explained by the subtraction of colors of light, related to the principles of absorption and reflection of light.

Poster showing a rebus on a signpost pointing to the right; the letter "i" in "right" is represented by an eye. Stamped: U.S. Navy Recruiting Station, 225 W. 42nd St., N.Y.C. Forms part of: Willard and Dorothy Straight Collection.

This lesson explores the senses of smell, touch, taste, sight, and hearing. It provides an opportunity for students to meet a doctor who will show them how the senses are used when examining patients. The lesson introduces Dr. Virginia Apgar and the use of the Apgar Score in examining newborn babies.

Poster for Federal Art Project exhibition of posters at the Cleveland Art Center, 4300 Euclid Ave., showing an eye with an arrow through it. Date stamped on verso: Apr 9 1938. Posters of the WPA / Christopher DeNoon. Los Angeles : Wheatly Press, c1987, no. 38

Poster for WPA Illinois Safety Division promoting safety and use of proper eye protection. Date stamped on verso: Apr 28 1937. Posters of the WPA / Christopher DeNoon. Los Angeles : Wheatly Press, c1987, no. 214