Last updated: May 28, 2024
Lesson Plan
Measuring the height of Saguaros using a clinometer
- Grade Level:
- High School: Ninth Grade through Twelfth Grade
- Subject:
- Math
- Lesson Duration:
- 60 Minutes
Objective
The objective of this lesson is to help students apply their knowledge of trigonometry in real life by connecting it to measuring the height of saguaros.
Background
Every ten years, Saguaro National Park leads a citizen science Saguaro Census to study the long-term health and vitality of the park's namesake cactus. Although we have studied saguaros at the park for many decades, beginning in 1990 scientists developed a new study to assess the overall conditions of saguaros across the entire park, including both the east and west districts. The saguaro census is meant to be repeated every ten years and coincides with the US Census. Beginning in late 2019 and continuing through late 2020, park scientists, staff, and citizen scientists will take data on tens of thousands of saguaros throughout the park. These data include measuring the height of saguaros found on each plot we're studying. The height of the saguaros tells us how many are old as well as how many are young. In a sense, it helps us in predicting how the plot is going to look like years after.
Preparation
Learn more about the Saguaro Census and how clinometers are used during a Saguaro Census
Print the Clinometer worksheet
Materials
Lesson Hook/Preview
Watch the video, Section 17, to get an idea of how saguaros are doing at the park and get a glimpse of a clinometer being used in action!
Procedure
#1: Talk to students about researches that have been done at Saguaro National Park, particularly the Saguaro Census.
#2: Watch the video on Section 17.
#3: Familiarize students on how to use a clinometer, how it works, and its relevance to the Saguaro Census. As a class, read "How clinometers are used during a Saguaro Census."
#4: As a class, brainstorm how the math behind finding the height of a saguaro using a clinometer relates to trigonometry. How is it different from how a clinometer is usually used to find the height of an object? How is it similar?
#5: Let the students work on the Clinometer worksheet by themselves. After, answer the worksheet as a class.
Vocabulary
Saguaro- a giant columnar (cylindrical) cacti that is native to the Sonoran Desert
Clinometer- an instrument used to measure slope
Slope- how steep a line is; rise over run
Trigonometry- studies the relationship between the lengths and angles of triangles