ALEX Lesson Plan

In this lesson, students will investigate how light rays reflect from the surface of an object and allow us to see the object by viewing several small items inside a black bag with and without the use of a light source. Students will work collaboratively on an online simulation to control the path of light in order to illuminate objects. Students will construct a model to describe how an object can be seen when light reflected from its surface enters the eye.

This lesson results from the ALEX Resource Gap Project.

Video:

The Visual System - How Your Eyes Work https://youtu.be/i3_n3Ibfn1c

Website:

Science Kids - How We See http://www.sciencekids.co.nz/gamesactivities/howwesee.html

Materials for Model:

• flashlight (one per group)
• a hand held mirror (one per group)
  
• stuffed animal (one per group)
  
• 4 meters of ribbon (one per group)
  
• chart paper (one per group)
• markers (one per group)
• The Eyes Have It Modeling Rubric (one per student, see attachments)
  
• The Eyes Have It Example Diagram (example for the teacher only, under attachments)
  

Materials for Seeing in the Dark Activity:

• flashlight
• black bag (to place small items inside, works best if the bag is cloth like a pillowcase)
• several small objects (examples:  toy car, pencil, small ball, LEGO or wooden block, etc.)
  
  

Other Materials:

iPads, Chromebooks, or another device with the internet (one per group)

projector, teacher computer with WiFi to access and play the video

For Students:

Students should have some basic knowledge about light energy and light sources.

For the Teacher:

Teachers should know that light reflects off objects and travels into the eye. Light travels through the lens to the retina, and the image is upside down. The optic nerve sends signals to the brain. The brain makes sense of the signals and tells us what we can see. 

For the Seeing in the Dark Activity teachers will need a black bag for each group (this works best if it is cloth such as a pillowcase). Collect several small items to place inside each black bag (examples:  toy car, pencil, small ball, LEGO or wooden block, etc.). For this activity, students will be divided into groups, each group will sit in a circle on the floor, and pass the black bag around in the circle.  Students will hold the bag close to their face, open it and view the contents inside, but do not tell others in the group what items they see.  After all groups have viewed the contents, the teacher will make a list of items students may have been able to see on the board.  Then, the groups will pass the same black bags around their groups again this time holding the bag at arm's length and shining a flashlight into the bag when viewing its contents.  Collaborate another class list for comparison.  Make sure the lights are dim before beginning this activity and only allow each student to view the contents in the bag for a 4-second count each time as time may become a factor.

For the Eyes Have It Modeling Activity (after activity) the teacher will need to make a copy of the rubric (under attachments, one per student) prior to the beginning of the lesson. Also, keep in mind, this model could look different for each group depending on the placement of their stuffed animal, mirror, flashlight, and where each student is standing (there is an example diagram under attachments for teacher viewing only). When grading the model using the rubric, the teacher should look for light traveling in a straight line from each of the elements in the model as well as the proper order of the model:  flashlight, stuffed animal, mirror, eyes. There is a sample diagram under attachments.

Caution students when using flashlights not to shine the light into their eyes or other students' eyes. 

Before

Engage:  Ask students to close their eyes and imagine the world without sight. How different would your world be? What sights would you miss the most?  What daily activities would be more difficult?  Would any be impossible?  How does the eye help us to be able to see?  Explain that today we will be learning about how we see things and how our eyes work.

During

Explore: Show the video: The Visual System - How Your Eyes Work https://youtu.be/i3_n3Ibfn1c

After viewing the video, have students turn to a partner and ask the following question: "Why is light important when it comes to seeing objects?" (possible response: light is reflected off objects and into the eye.) Lead a discussion explaining that in order for us to see an object, light has to reflect off that object and enter our eyes. We can see in the dark, but there must be a light source such as the moon for us to be able to see objects. 

Say, "If you have ever tried to see in a completely dark room before it is very hard to see. If there is no light, we cannot see. Let's do a test to demonstrate this." Place students in groups of 4 students per group. Distribute materials for Seeing in the Dark Activity (one black bag containing small items, and a flashlight for each group).  Each group will sit in a circle on the floor. Give each group their black bag containing small objects (make sure none of the students saw you place the objects in the bag before the activity). Dim the lights. Tell the students to hold the opening of the bag close to their face, open it and view the contents, but don't tell any of the other group members what they see. Only allow students a 4-second count to view the objects in the bag as time may become a factor in this activity. The group will pass their bag around the circle for all members to view the contents. Then, as a class, ask, "What objects did you see?" Make a list of any objects the students were able to name on the board.  

Say, "Let's see what happens if we add a light source." This time the students will pass the black bag containing the items around the circle holding the bag at arms distance, open it and shine the flashlight inside the bag. Again, they should not yell out any items they are able to see. When all students in the groups have viewed the contents of the bag, ask, "Did you see any objects that you didn't see the first time? Why?" Explain that when there was no light source in the bag, the students could not see the objects inside it. When they shined the flashlight in the bag, they could see the objects because light bounced off the objects in the bag and traveled into their eyes.      

Explain:  Have students visit the following website:  Science Kids How We See (http://www.sciencekids.co.nz/gamesactivities/howwesee.html). Students will play an interactive game using lights and mirrors to control the path of light and illuminate objects. Students will work together collaboratively as a group to decide how to change the mirror to change the direction of the light. Only one computer or mobile device connected to the internet will be needed.

After

Elaborate:  Say, "We need a light source to be able to see, and we know that light reflects off an object and enters our eyes enabling us to see. Now we are going to construct a model to demonstrate how light travels from a light source, reflects off an object and then enters the eye. Remember light travels in a straight line. You will use a ribbon to represent the light, so you will need to make sure when you are holding the ribbon, you pull it tight." Place students in groups of 4 students per group. Distribute the materials:  The Eyes Have It Modeling Rubric (one per student, under attachments), a stuffed animal, a mirror, a flashlight, and 4 meters of ribbon. One student in the group should hold the mirror in front of them while another student in the group places the stuffed animal on a table or chair close to the student holding the mirror. A third student will shine the flashlight, while the fourth student represents the "eyes". The student holding the mirror should stand still, but the student representing the eyes may need to keep re-positioning themselves until the stuffed animal is visible in the mirror. All students should be holding on to the ribbon and connecting the ribbon to each object ending with the eye. Some students may need guidance from the teacher to complete this model correctly (There is a sample diagram under attachments for teacher viewing only. Keep in mind student models will vary due to the placement of each element in the model). Distribute chart paper and a marker and ask the groups to draw their model on a piece of chart paper and explain what is happening. Students should use vocabulary and have at least 3 facts on their drawing (example:  light travels in a straight line, light reflects off an object and enters the eye, need a light source to see objects).

Formative assessment for this lesson is based on teacher observation. (Did the student struggle with the interactive game Science Kids How We See  (http://www.sciencekids.co.nz/gamesactivities/howwesee.html)? Is the student able to provide input during the construction of the model, or does he/she require quite a bit of assistance from other group members?)  Formative assessment should demonstrate a progression of learning for this concept.  This should be evident during the interactive game as proper placement of the mirrors will allow advancement in the game Science Kids How We See  (http://www.sciencekids.co.nz/gamesactivities/howwesee.html).  

Summative assessment for this lesson is based on The Eyes Have It Modeling Rubric (under attachments).

Students can research a vision problem or disease, such as nearsightedness, farsightedness, astigmatism, color blindness, or cataracts.  Students can create a poster, pamphlet, or PowerPoint to present to the class that explains the causes, treatment, and any technology or surgical procedures used to enhance treatment. 

Students who need extra support should be placed in groups with teammates sensitive to the needs of that student. The teacher may need to more closely supervise teams that contain students who are struggling with the concepts of this lesson. Students may also be given additional time to complete the activities of this lesson.