Grade Level: 6th – 8th grade
Subject Matter: Physical Science
National Standards: NS.5-8.1, NS.5-8.2
Toilet paper tubes – four for each student
Sheets of black construction paper – four pieces for each student
Rubber bands – eight for each student
Wax paper (cut into four by four-inch squares) – one square for each student
Tracing paper (cut into four by four-inch squares) – one square for each student
Tissue paper (cut into four by four-inch squares) – one square for each student
White plastic bag (cut into four by four-inch squares) – one square for each student
Aluminum foil (cut into four by four-inch squares) – one square for each student
Roll of Scotch or masking tape
Box of pushpins
Pinhole viewer: an optical device with a pin-sized hole that creates an image.
Reflection: the change in the direction of light as it bounces off an object.
Telescope: instrument used to look at distant objects.
Retina: inner part of the eye that receives and transmits images to the brain via the optic nerve.
Pupil: opening in the eye that regulates the amount of light that enters the eye.
1. Begin the lesson by having the students watch the Science Friday video, “Building an Observatory.” Ask students to describe what they saw in this video, and suggest how they think this video was created. Inform students that as the dome was constructed, a camera was programmed to take a picture every few minutes – a total of more than 200,000 images. Then selected images were compiled into a time-lapse video.
2. Ask students if they can compare how our eyes work to how a camera or telescope works. What is needed in order for any of these three to function properly? Allow students to share their ideas and suggestions with the class, before you mention that light is an important component in the proper functioning of all of these things. Inform students that by constructing pinhole viewers, they will observe the importance of light to making an image.
3. Hand out one toilet paper tube and one four by four-inch square of wax paper to each student. Have students completely cover one end of the toilet paper tube with wax paper, and secure it in place with a rubber band. There should be very few or no wrinkles in the wax paper.
4. Instruct students to roll the piece of black construction paper to form an outer tube around the toilet paper tube, so that the toilet paper tube end covered in wax paper is inside the black construction paper tube. The open end of the toilet paper tube should be aligned with the end of the black construction paper tube. Students should secure the black paper with tape and label the construction paper tube, “Wax Paper.”
5. Have students cover the open end of the toilet paper tube with a square of aluminum foil, and secure it in place with another rubber band. Then they should use a pushpin to carefully poke a small hole in the center of the aluminum foil.
6. Have students label a clean piece of paper or a page in their science notebooks, “Pinhole Observations.” Underneath, they will record their predictions and observations. Ask students to start by predicting what they think they might see when they look through the pinhole viewers, and then recording their predictions.
7. Take students outside with their pinhole viewers and observation sheets. Demonstrate how to use the pinhole viewer by looking into the open end of the black construction paper tube. Pinhole viewers work best in bright sunlight, by looking at the tree or roof line against the sky.
8. Have students look through the pinhole viewers and record their observations. They should include sketches whenever possible. Is the image clear? Is the image in color? Does the image appear right-side up?
9. Back in the classroom, ask students to share their observations. Were any predictions correct? Was anyone surprised by the results?
10. Tell the students that they are going to test various materials to determine which material produces the sharpest image in their pinhole viewer.
11. Hand out to each student three more toilet paper tubes, and one square each of tracing paper, white plastic, and tissue paper.
12. Have students repeat steps 3 to 5 to create three new pinhole viewers. Make sure students label each new pinhole viewer with the corresponding material being used: i.e., “Tracing Paper,” “Tissue Paper,” “White Plastic.”
13. Repeat steps 7 to 8, with students using the new pinhole viewers to make and record their predictions and observations.
14. Have a class discussion on which material produced the sharpest image. Did everyone agree on which material was the best? What could be some possible reasons for the differences in the clarity of the image?
The time-lapse video, “Building an Observatory,”” shows the construction of a dome that houses and protects a new planet-hunting telescope. This telescope, as well as the camera used to document the dome’s construction and the eyes that we used to view this time-lapse video, all work in similar ways, in that they all require light. We cannot see without light reflecting off an object and entering our eyes. That is why we are not able to see in the dark if there is absolutely no light present.
• What are some applications of pinhole viewers or cameras?
• What might happen if we try using our pinhole viewers on a cloudy day? At night?
• How do astronomical researchers use the telescopes at Lick Observatory to learn about the Universe?
Extend the activity by having students re-design their pinhole viewers so that they generate a larger image, or a more focused image or an image that is right-side up.