Physical and Chemical Changes

Objectives:

• Students will be able to distinguish between physical changes and chemical changes.

• Students will be able to describe what happens when substances react and undergo chemical changes.

• Students will be able to identify a chemical equation and state what it represents.

• Students will be able to recognize some of the signs of chemical changes.

Suggested Grades:

5th Grade - 6th Grade - 7th Grade

Lesson Procedure:

Print the reading comprehension worksheet passage and questions (see below).

Students should read the passage silently, then answer the questions. Teachers may also use the text as part of a classroom lesson plan.

Lesson Excerpt:

Matter changes all the time. There are two types of changes that matter can undergo: physical changes and chemical changes. When matter changes from one state to another, but keeps its identity it undergoes a physical change. For example, when liquid water freezes and becomes ice, it changes physically, but it is still water.

When matter undergoes a chemical change, one or more completely new compounds are formed. The atoms between chemicals link together in new ways to create new substances. An example of a chemical change is the reaction between baking soda and vinegar. If you mix these two substances together, you will notice that gas bubbles form. A chemical reaction is occurring. The bonds in the baking soda and vinegar atoms are broken and new bonds form. The result is three entirely new substances: water, carbon dioxide and sodium acetate.

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