Classification of Matter
Classifying Matter
Imagine walking outside on a cold winter day. If you live in a cold part of the country, you might imagine a snowy day, but in warmer parts of the country, the precipitation you see is more likely to be rain than snow. What is the difference between snow and rain? Both are forms of water, but what distinguishes one from the other? In some parts of the world, the snow forms into large rivers of ice called glaciers. What properties of snow allow glaciers to form?
Glaciers are produced as snow falls but doesn't fully melt throughout numerous years, resulting in a buildup. The compression of the snow produces a tremendous mass, eventually transforming it into ice. Scientists have discovered, however, that as global temperatures rise, glaciers are melting at unprecedented levels. How does the mass of ice in the glacier change as it melts? The melting of a glacier is similar to an ice cube melting if you place it on a bowl and let it sit in a warm room. How would its properties change if you placed the melted ice back in a freezer?
You encounter different forms of water in many aspects of your life. For example, what causes water droplets to form on the outside of a glass of a cold drink? Why do you feel so uncomfortable on a day with high humidity? If you have ever boiled water to make noodles, you have probably seen a mist of water droplets rising from the pot. What causes the mist to form? Why does it disappear to form steam after a few seconds? How are properties of the steam different from properties of water in the pot?
The picture of lava flowing into the ocean shows an example of steam forming in nature, but steam has many useful familiar applications as well. Consider, for example, the use of steam for cleaning and energy production. Steam cleaning a carpet, for example, is a method of cleaning without using harsh chemicals that may pose a health risk to individuals. The majority of the world’s electrical energy is produced with the use of steam to turn the blades of turbines.
Explain Question
Explain how different states of matter are distinguished from each other, and how pure substances are distinguished from mixtures.
Teacher Note
Use this student response to evaluate students’ prior knowledge of the concept. The Model Lesson provides information on common student misconceptions. This item should be used as a formative assessment.
Before You Begin
What do I already know about the classification of matter?
Teacher Note
This activity is intended to provide the teacher with feedback on existing student knowledge of this topic. In middle school, students should have learned that elements are the simplest form of matter and compounds consist of two or more elements that are chemically combined. This activity should be used as a formative assessment.
Teacher Note
This item is intended to assess prerequisite knowledge of solids, liquids, and gases. This item should be used as a formative assessment. Have students complete the activity independently and then discuss their answers as a class.
Teacher Note
This activity is intended to assess whether students have a misconception about how pure substances can be separated and how mixtures can be separated. This activity should be used as a formative assessment. Use students’ responses to this question as a guide for discussing methods of separating substances.
Teacher Note
This activity is intended to provide the teacher with feedback on prior knowledge of this topic. Its main focus is to determine whether students are familiar with classifications of matter and if they can correctly label an item. Have students complete the activity independently, but afterwards discuss the answers as a class. This activity should be used as a formative assessment.
Find Out More About...
- atoms and elements
Lesson Questions
- How are the four states of matter described?
- How are pure substances and mixtures distinguished?
- What is a mixtureglossary term (opens in a new window)?
- How are different types of mixtures distinguished?
