The Chumash Science Through Time Project developed a 5th grade lesson plan that combines the objectives of understanding the Earth’s place in the universe and understanding Indigenous knowledge as scientific and relevant. This lesson uses Next Generation Science Standards combined with astronomical knowledge associated with a Chumash tree carving. It can be adapted into more advanced versions or more foundational versions, and we are happy to work with teachers to help them fit it to their needs.
- NGSS 5-ESS1-1 Earth’s Place in the Universe: Support an argument that the apparent brightness of the sun and stars is due to their relative distances from the Earth.
- NGSS 5-ESS1-2: Represent data in graphical displays to reveal patterns of daily changes in length and direction of shadows, day and night, and the seasonal appearance of some stars in the night sky,
To understand the concepts behind a Chumash calendar found in a tree carving, this lesson includes a lab activity where students explore how changing the angle at which light hits an object impacts the length of the object’s shadow, and a Crash Course Video that demonstrates how shadows change in direction and length as the sun’s position changes in the sky. This information sets the foundation for students to understand how Chumash astronomers created a calendar of “holidays” with a sundial-like instrument.
The “Shadows Exploration” Lab Activity was designed to be less than 30 minutes. In this activity, students will explore how changing the angle at which light hits an object impacts the length of the object’s shadow. Students will have the opportunity to reflect, explore, collect and analyze data, and then discuss what they have observed. In addition to activity printouts, each activity in the NGSS in 30 minutes or less series will provide you with one or more essential questions, the related NGSS Disciplinary Core Idea and Science & Engineering practice, lesson objectives, discussion questions, activity extension suggestions, and post activity assessment. (Developed for Jessica Horton on teacherspayteachers.com, free digital download)
The Crash Course Kids: Following the Sun & Seasons and the Sun explanatory videos demonstrates how shadows change in direction and length as the sun’s position changes in the sky and explains the sun’s impact on seasons.
The Sun Shadows and the Chumash Calendar Handout and the Chumash Science Through Time Arborglyph Video provides information on a Chumash tree carving that is a calendar that represents important parts of the year for Chumash people, at summer solstice, fall equinox, winter equinox, and spring equinox. The calendar is etched from the shadow of the sun throughout the year on a sundial that was aligned with the North Star. This helps students understand that knowledge of the Earth’s position in the Universe gave Indigenous people the ability to keep track of time.
The sun is stationary in relation to the Earth. It appears to move across the sky because the Earth is rotating on its own axis every 24 hours, producing night and day. The tilted axis of the Earth as it revolves around the sun causes variations in the directness of the sun’s rays and the length of the day, depending on latitude and the time of year. In the Northern Hemisphere, the sun reaches its highest angle above the horizon at solar noon on summer solstice (about June 21). Its lowest “high” occurs at solar noon on winter solstice (about December 21). In the Southern Hemisphere, the highest angle occurs on the winter solstice and the lowest “high” on the summer solstice. Within the tropics, the sun reaches its maximum angle, 90°, twice a year. At the Equator this happens on the two equinoxes.
The sun’s angle above the horizon determines the directness of the sun’s rays which, in turn, determines the amount of heat energy a given location on Earth receives. If the sun is 90° above the horizon, straight overhead, that location is receiving the most direct rays possible. These perpendicular rays are intensely concentrated, emitting the greatest amount of heat energy. The lower the sun’s position in the sky, the more indirect the rays. The same amount of sun’s rays are spread over a larger area so less heat energy is received in a given location. Differences in the heating of the Earth’s surface triggers our planet’s weather. And because the changing position of the Earth in relationship to the sun is repeated on a yearly basis, a predictable cycle of seasons is experienced in some form throughout the world.
The Chumash Arborglyph, or tree carving, was found in the Northern part of the Chumash territory, North of San Luis Obispo. This tree carving demonstrates the scientific nature of Indigenous knowledge, by using the sun, moon, and stars, to keep track of time. The bottom part of the image (shown on the Handout), which looks like a person or animal, is a calendar that represents important parts of the year for Chumash people, at summer solstice, fall equinox, winter equinox, and spring equinox. The calendar is etched from the shadow of the sun throughout the year on a sundial that was aligned with the North Star. The top part of the image is a calendar as told by the stars, tracing the movement of the Big Dipper around the North Star.
The “Shadows Exploration” Lab Activity
Materials List Per Group
- 1 light tool* (* See Assembly Instructions, pg 3)
- 1 shadow exploration tool*
- 1 Lego Minifigure
- 1 red colored pencil
- 1 ruler
For your students to be able to complete the activity in the timeline indicated, all materials should be gathered, assembled and/or divided ahead of time. Also, please have student groups pre-assigned (3-4 students per group). Please see Assembly Instructions for more information on the light tool and shadow exploration tool.
- (~ 20 min) Break students into small groups and distribute the materials indicated. Model the placement and movement of the meter stick on the shadow exploration tool. Give students an opportunity to collect data using the student record sheet.
- (~2 min) Collect materials. Have students begin the post activity discussion in groups.
- (~5 min) Have groups share their findings and draw connections towards the objective – accurately describe how changing the angle at which light hits an object impacts the length of the object’s shadow.
Gather These Materials Prior To Assembling the Light and Shadow Exploration Tools:
- Manila file folders
- Masking Tape
- Grid Paper
- Metersticks or rulers
Creating the shadow exploration tool (see visual for additional assistance)
1) Glue a piece of grid paper down onto one half of a file folder.
2) With a ruler, find and mark the midway point on the
crease of your folder (where the two halves join). We
will call this your center dot.
3) Place a protractor’s center hole over the mark you made with the rounded edge on the side without grid paper. Make marks on the 0, 30, 60, 90, 120, 150, and 180 angle lines. Using the ruler draw the lines out from the center mark to each edge of
the file folder.
4) Label each line with the degrees of the angles 0, 30, 60, 90, 60, 30, 0.
5) Directly underneath the center dot, draw a 4 cm long line perpendicular to the crease. Now draw a 4 cm square left of the line 1 cm away. Repeat for the right side of the line. Write “ruler here” below the line.
Creating the light tool
1) Using masking tape, secure a flashlight to a meter stick so that the light source is exactly at the 20 cm mark pointing towards 0. Make sure not to cover the on switch with the tape.
- Were you able to change the direction of your shadow? Or was the shadow cast the same direction through the entire activity? If you were able to change the direction of the object’s shadow, how were you able to do it?
- Were you able to change the length of your shadow? Or did the shadow stay the same length through the entire activity? If you were able to change the length of the object’s shadow, how were you able to do it?
The Crash Course Kids
- Following the Sun (5 min) https://www.youtube.com/watch?v=1SN1BOpLZAs
- Seasons and the Sun (5 min) https://www.youtube.com/watch?v=b25g4nZTHvM
Discuss how in summer the Northern Hemisphere is facing the sun, and in the winter the Northern Hemisphere is facing away from the sun. In front of the class, recreate the lab experiment with the flash light placed at greater distances on the meter stick. Try 40 cm and/or 60 cm and discuss the change in shadow length change and relate it to winter vs. summer.
See: Chumash Calendar Handout (Read as a group or individually.)
Watch: Chumash Science Through Time Arborglyph Video (3:24): https://youtu.be/vx2gpZpCTeY
- How does the lab activity relate to the Chumash Calendar?
- How does the length of a shadow in winter differ from the length of a shadow in summer? How is this shown on the Chumash Calendar?
See: Post Activity Quiz
This lesson plan was developed by Sabine Talaugon. If you have questions, or would like to figure out how to create an Indigenous science lesson plan for your classroom, please contact Sabine through our Contact Page.