By Shuana Jordan
Product Developer

Introduction

Students are taught that matter exists in different states, has various characteristics, and can be classed into basic categories. Students who can easily memorize the defining features and names of these categories often struggle when asked to identify and classify actual examples of matter around them.

Four basic questions must be answered about a material in order to classify it:

1. Can physical separation techniques be used to separate the matter? If yes, then it is a mixture. If no, then it is a substance.
2. If it is a substance, can it be broken down by chemical processes? If yes, it is a compound. If no, it is an element.
3. If it is a mixture, does it have uniform composition? If yes, it is a homogeneous mixture, such as a solution. If no, it is a heterogeneous mixture.
4. If a material is a heterogeneous mixture, do the particles settle to the bottom? A suspension’s particles do, while a colloid’s do not.

In this lab activity, students rotate from station to station in small groups and answer each of these basic questions as they test and classify different examples of matter. This activity is appropriate for a class of 30 middle or high school students working in groups of 3.

National Science Education Standards

Physical Science

Grades 5–8

• Properties and changes of properties in matter

Grades 9–12

• Structure and properties of matter
• Chemical reactions

Safety

Model and require proper laboratory safety practices during this activity. Follow your school guidelines for disposal of laboratory waste.

Materials

• 4 250-mL Beakers
• Saltwater
• Milk of Magnesia
• Muddy Water
• Oil and Vinegar Salad Dressing
• Can of Shaving Cream
• Aluminum Foil
• Iron Filings
• Sugar
• Bare Copper Wire
• Baking Soda
• 10 Index Cards
• Marker
• Copies of the Classifying Matter Data Sheet (1 per student)

Preparation and procedure

1. Gather or prepare the materials.
2. Set up 10 stations so that the groups can rotate around the classroom or lab and classify each of the 10 examples of matter.
3. Make an index card label for each material, and place the labels at the stations.
4. Divide your class into groups of 3 students.
5. Have the groups rotate through the stations and complete the Classifying Matter Data Sheet.
6. After students have classified the 10 examples, go over their findings together. There may be some discrepancies that lead to a lively discussion and further exploration.
7. Have students create a flowchart incorporating the 4 questions from the data table and then try it with their own examples of different types of matter.

Conclusion and extension

This introductory activity helps students connect their chemistry study with their everyday world, and it reinforces the methodology behind classifying matter.

To extend the activity, have students brainstorm methods for physically separating the various materials that they identified as mixtures. Arrange for them to try some of the methods.

Additional resources

• Inquiries in Science®: Understanding Properties of Matter Kit
• Carolina ChemKits™: Elements, Compounds, and Mixtures
• Pyrex® Vista™ Beakers