What our Human Eye lesson plan includes
Lesson Objectives and Overview: Human Eye explores the different parts and functions of eyes. Students will discover how this part of the body allows us to process light and visualize color. They will also learn about tears and how the lacrimal glands release moisture for a number of different reasons. This lesson is for students in 4th grade, 5th grade, and 6th grade.
Every lesson plan provides you with a classroom procedure page that outlines a step-by-step guide to follow. You do not have to follow the guide exactly. The guide helps you organize the lesson and details when to hand out worksheets. It also lists information in the yellow box that you might find useful. You will find the lesson objectives, state standards, and number of class sessions the lesson should take to complete in this area. In addition, it describes the supplies you will need as well as what and how you need to prepare beforehand. For this lesson, you will need colored pencils and small flashlights for the activity portion.
Options for Lesson
The “Options for Lesson” section contains several ideas for additional activities and exercises to add to the lesson if you want to extend it or have extra time. One idea is to go through the content pages before distributing the activity. You could choose to assign the practice page as the homework and vice versa, using the crossword as an in-class assignment. Another option is to assign students to research other aspects about eyes, such as eye problems, color variations, color-blindness, and so on. You could let students choose or decide for them which topic they should research. Students could even create presentations to show the class that showcase what they learned during their research.
The paragraph on this page gives you a little more information on the lesson overall and describes what you may want to focus your teaching on. It reminds you to stress the importance of eye safety and also suggests looking at the “Options for Lesson” section for more ideas. The blank lines are available for you to write out any thoughts or ideas you have as you prepare.
HUMAN EYE LESSON PLAN CONTENT PAGES
Introduction to Eyes
The Human Eye lesson plan contains three content pages. The reason we can read words on paper is that our eyes let us see. All the different parts of the eye work together so that we can watch a sunrise or admire the moon. Some of these parts are visible to us if we look in a mirror, but not all of them.
The lesson provides a diagram of the eight main parts of an eye for students to review. The eight parts are the iris, retina, optic nerve, pupil, lens, sclera, cornea, and anterior chamber. Eyes are situated inside a hollow area of the skull called the eye socket. Our eyelids protect the front part of our eyes, keeping them clean and moist by blinking.
What’s interesting about blinking is that it is both a voluntary and an involuntary movement. Sometimes we choose to blink (voluntary), but other times, our eyes blink automatically (involuntary). When the eye blinks automatically, this is a reflex. The reflex occurs when our eyes need to adjust to bright light or when we need to shut them quickly for protection from dirt or other substances.
Eight Major Parts of the Eye
There are eight main parts that make up the eye. The sclera is the white part, the outer covering of the eyeball that is made of a very tough material. It also contains blood vessels that deliver blood to the sclera. The cornea is a transparent dome in front of the colored part of the eye. It helps us focus when light enters. It’s hard to see because it’s a clear tissue.
The colorful part of the eye is the iris. Certain muscles attach to the iris that change its shape and control how much light can enter into the pupil. The pupil is the black circle in the middle of the iris that lets light enter. Pupils adjust to the light by opening wider when we need more and shrinking when there’s plenty available. Between the iris and cornea is the anterior chamber, which is filled with a transparent fluid that keeps the eye healthy.
When light enters the eye, it hits the lens behind the iris. The lens is also transparent, and like all lenses, their responsibility is mainly to focus light. Specifically, it focuses light rays on the back of the eyeball to the retina. The retina is home to millions of cells that are sensitive to light. The retina takes the light and changes it to signals that it can then send to the brain.
The brain in turn is able to tell a person what they are looking at. Students will discover that the image the eye receives is actually upside down when the optic nerve sends the signal to the brain. The optic nerve is like a high-speed telephone line. By the time the brain receives the message, however, the image we see is right-side up. This process happens so fast that we don’t even realize it.
Other Parts of the Eye
Apart from the eight main components, students will learn a little about other parts that make up the eye. A muscle inside our eyes called the ciliary muscle changes the shape of the lens when we need to see close up, far away, or out of the corners of our eyes. The lens becomes thicker for things we want to see up close and thinner when we want to see far away.
The largest part of the eye is the vitreous body, which takes up about two-thirds of the volume of the whole eye. The rods and cones are much smaller. The retina uses special cells called rods (around 120 million) and cones (about 7 million) to help process light. Rods see in black, white, and gray, and they pass along the shapes that we look at. They can also tell the difference between colors and help us see when there isn’t much light.
Cones are more helpful when there is a lot of bright light. There are three types of cones in the retina that help us see different colors and shades. The light waves come together and enable us to see millions of different colors. All these parts come together to help us process what we observe through our eyes every day.
However, sometimes focusing can be an issue, either because a certain part of the eye isn’t working properly or because of tears. Located in the corner of each eye are lacrimal glands. These are responsible for producing tears. Every time we blink, a little moisture releases to wash away particles that don’t belong in our eyes.
HUMAN EYE LESSON PLAN WORKSHEETS
The Human Eye lesson plan includes three worksheets: an activity worksheet, a practice worksheet, and a homework assignment. Each worksheet reinforces the lesson concepts and provides students the opportunity to showcase what they learned. Refer to the guide on the classroom procedure page, which describes when to distribute each worksheet to the class throughout the lesson.
EYE OBSERVATIONS ACTIVITY WORKSHEET
Students will work with a partner for much of the activity, which focuses on various aspects of sight and the eyes in general. First, students will learn a little about depth perception using pencils. They must try a few times to touch the eraser ends together with one eye closed and then again with both open. They will then write what they notice in the space provided. Next, each partner will take turns shining light in the other person’s eyes with a flashlight to see what happens to the pupil.
Students will then take turns drawing pictures of their partner’s eye, including as much detail as possible. The next section focuses on reflexes. Each person will move their hand quickly and closely (without touching) to their partner’s face and write down what happens. Finally, students will discuss times that their eyes teared up or became watery. They will compare their stories to see what they might have in common and write down why they think their eyes make tears.
LABEL THE DIAGRAM PRACTICE WORKSHEET
For the practice worksheet, students will review a diagram of the side view of an eyeball. Using the terms in the word bank at the top of the page, they will label the eight parts of the eye. You may choose not to allow students to use the content pages for reference as they work on this worksheet since the diagram comes directly from those pages.
HUMAN EYE CROSSWORD PUZZLE HOMEWORK ASSIGNMENT
The homework assignment requires students to complete a crossword puzzle based on what they learned. There are 19 total clues to solve. Again, you can decide whether or not you want to allow students to refer to the content pages for help to complete this assignment.
Worksheet Answer Keys
If you choose to administer the lesson pages to your students via PDF, you will need to save a new file that omits these pages. Otherwise, you can simply print out the applicable pages and keep these as reference for yourself when grading assignments.