Sight Sleuths Worksheet
Grade 2–3 Informational Reading
Sight Sleuths: Central Idea Quest
Chapter 7: Eyes and Vision • Finding What the Text is Mostly About
Name:
Date:
Detective Strategy: The Central Idea tells what a page or paragraph is mostly about. Ask yourself: Who or what is this text discussing, and what is the biggest point the author makes?
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Part 1: Page-by-Page Central Ideas
1. [Page 52] Dr. Welbody welcomes a guest speaker to the class. What is the central idea of Page 52?
Page 52
Write 1 complete sentence explaining why Dr. Welbody brought Dr. Kwan Si-Yu to class.
2. [Page 54] Dr. Kwan Si-Yu begins by teaching the two parts of the eye you can see on a person's face. What is the central idea of Page 54?
Page 54
A. Some people have green eyes while other people have brown eyes.
B. The two visible parts of the eye are the colorful iris and the light-controlling pupil.
C. Optometrists use bright lights when examining a patient's pupil.
3. [Page 56] Page 56 describes the parts of the eye inside the head (cornea, lens, retina, optic nerve). What is the central idea of Page 56?
Page 56
State the central idea and list two inside parts mentioned on the page.
Central Idea:
Two Key Parts:
Sight Sleuths • Student Worksheet Page 1 of 2
Sight Sleuths: Paragraph & Chapter Spotlight
Chapter 7: Eyes and Vision • Close Reading Practice
Pages 58 & 59
4. [Page 58 as a Whole] Read Page 58 carefully. How do all the eye parts work together? What is the central idea of Page 58?
Page 58
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Part 2: Paragraph-Level Close-Ups
5. Paragraph Spotlight: The Changing Pupil Page 54, Paragraph 6
“The pupil is not as colorful as the iris. It is always black, but it changes size. When it is dark, the pupil gets bigger to let more light in. When it is very bright and sunny, the pupil shrinks to let less light in. How much light will be let into the inside of your eye depends on the size of the pupil.”
What is the central idea of this single paragraph? What supporting detail shows when the pupil shrinks?
Paragraph Main Idea:
Supporting Detail:
6. Paragraph Spotlight: Rods and Cones Page 58, Paragraph 4
“The retina is lined with special cells called rods and cones. These are special kinds of nerve cells that sense light. The rods and cones send information to the brain, using the optic nerve.”
In your own words, what is the central idea of this paragraph?
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Part 3: Whole-Chapter Big Idea
7. The Big Picture: What is the central idea of Chapter 7 (“Eyes and Vision”) as a whole?
Combine what you learned about the parts of the eye and the job they do with light. Write 1–2 complete sentences.
Sight Sleuths • Student Worksheet Page 2 of 2
Sight Sleuths Answer Key
Teacher Resource • Answer Key Standards: CCSS RI.2.2 / RI.3.2
Sight Sleuths: Answer Key & Guide
Chapter 7: Eyes and Vision • Central Idea & Supporting Details
Grades 2–3
Teaching Note: A central idea must express the author's primary takeaway, not just a standalone interesting fact. Guide students to ensure their response connects the topic with the author's main point.
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Part 1: Page-by-Page Central Ideas
1. [Page 52] Dr. Welbody Introduces Dr. Kwan Si-Yu Page 52
Exemplar Central Idea:
Dr. Welbody brings in Dr. Kwan Si-Yu, an optometrist (eye doctor), to teach the class how the eyes work and explain vision.
Acceptable Variations: Students should mention both that Dr. Kwan Si-Yu is visiting and that his role is to teach about how eyes and vision function.
2. [Page 54] Visible Parts of the Eye (Iris & Pupil) Page 54
Correct Answer: B
“The two visible parts of the eye are the colorful iris and the light-controlling pupil.”
Distractor Analysis: Option A (eye colors) is only a single detail in paragraph 5. Option C mentions eye doctors shining lights, which is a supportive example, not the page's central focus.
3. [Page 56] Inside Parts of the Eye Page 56
Exemplar Central Idea:
Inside the head, the eye has hidden parts (cornea, lens, retina, and optic nerve) that protect the eye and capture light signals to send to the brain.
Acceptable Key Parts (Any 2): Cornea (protects/covers), Lens (focuses light), Retina (light-sensitive tissue), Optic nerve (sends messages to brain).
Sight Sleuths • Teacher Answer Key Page 1 of 2
Sight Sleuths: Paragraph & Chapter Key
Exemplar Responses & Misconception Guidance
Pages 58–59 & Summary
4. [Page 58 as a Whole] How Eye Parts Work Together Page 58
Exemplar Central Idea:
Vision happens when reflected light passes through the cornea, pupil, and lens onto the retina, which sends signals through the optic nerve to the brain.
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Part 2: Paragraph Close-Up Solutions
5. Paragraph Spotlight: The Changing Pupil (Page 54, Para 6) Page 54
Paragraph Main Idea: The pupil changes size to regulate how much light enters the inside of the eye.
Supporting Detail: In bright sunlight, the pupil shrinks to let less light in (or in dark places, it gets bigger to let more light in).
6. Paragraph Spotlight: Rods and Cones (Page 58, Para 4) Page 58
