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Explore the slideshow below to learn how to identify the central idea in science text and the evidence that best supports the central idea. You will also learn how to write a summary or analysis of the most important information that you have learned.

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Central Idea and Evidence

central idea magnified

As you prepare to read, think about the central idea of the text. Read the title and notice any prominent text features such as photographs and captions. Ask yourself:

  • What is the most important idea in this text?
  • What is the biggest idea?
  • What does the author want me to learn?
  • Why does this information matter?
evidence magnified

As you read the first paragraph, look for specific evidence that supports your understanding of the central idea. Evidence could be facts, quotations from experts, explanations of experiments or research, and/or text features that may include photographs, graphs, charts and diagrams.

central idea and evidence magnified

As you continue reading, think about and analyze the evidence that the author is including to prove the central idea. Ask yourself questions about why the author might have included specific evidence.

  • How does the evidence relate to the most important point the author is trying to make?
  • Does the evidence help to reveal the central idea?
  • Is the evidence significant and relevant?

Questions to ask:

  • What is the central idea of this section?
  • How has the central idea changed from the last section I read?
  • What evidence supports my growing understanding of this topic or concept?

The central idea will develop over the course of the text. One way to keep track of this development is to pause after a section of reading and ask yourself these questions.

evidence pointing to central idea

Continue examining the evidence as the text unfolds. Synthesize the evidence to determine the overall central idea.

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The central idea and the most important supporting evidence is the foundation of a good summary.

'Focus on the WHAT' above central idea and evidence magnified image
When you summarize a text, you begin by clearly identifying the overall central idea and evidence that supports the overall central idea. Remember, when composing a written summary:
  • Write in your own words.
  • Focus on the WHAT (the central idea and evidence).
'HOW does the author present information?' above central idea and evidence magnified image

When you write a summary, you look critically at HOW the author presents the information. To do this, you must identify the central idea and then consider how the author used significant and relevant evidence to support the central idea.