The ability to summarize what you have read is an essential research skill.  When you look for information, you can't just copy and paste what you find into your own work.  If you're going to write about a topic, you have to have a clear summary of it in your head first.  To build that summary, you start with information.  You need to read it, understand it, and be able to express it in your own words.  Summarizing is great practice for doing research.

How to summarize a passage

Skim the text to get a general idea of the topic

Ignore unnecessary or redundant material

Find the main ideas in the text: look for words like therefore, in conclusion, or in summary

Find or create a topic sentence

Substitute general or "umbrella" terms when you can (for example,trees instead of oak,maple, and pine)

Explain new vocabulary from the text or replace it with your own vocabulary 

Here is a sample for the class to do together: How did people solve a problem?

Practice

Below are three passages for you to read.  For each passage, write a note card that summarizes it.  You may only use one side of the card.