States of Matter

Physical Science

Solids, liquids and gases are states of matter that have unique properties.

Benchmark: Comparing States of Matter

Distinguish between solids, liquids and gases in terms of shape and volume.

For example: Water changes shape depending on the shape of its container.

Benchmark: Changes of State

Describe how the states of matter change as a result of heating and cooling.


Standard in Lay Terms 

MN Standard in Lay Terms

All the material on earth is in three states: solid, liquid, and gas.

Big Ideas and Essential Understandings 

Big Idea

Students in grade three must understand that matter is a substance that occupies space and may assume the form of a solid, liquid, or gas.  Students should view pictures and read articles about lava and molten steel to make the point that most substances can turn to liquid when heated to a high enough temperature.  Likewise, a gas can turn to a solid if sufficiently cooled.  For example, carbon dioxide, a gas at room temperature, can be frozen into dry ice.  Source: Excerpt from California Science Framework.pdf, pg. 47 Note: At this level students are not expected to explain what is occurring at a particle level.

Benchmark Cluster 

MN Standard Benchmarks  Distinguish between solids, liquids and gases in terms of shape and volume.  For example: Water changes shape depending on the shape of its container.  Describe how the states of matter change as a result of heating and cooling. 

The Essentials



Ronnie never listens in science class because he says it's boring.

One day his teacher asked, "Ronnie, What are the 3 states of matter?"

Since he heard his name he did listen to the question. So he thinks for a second and replies, "Texas, Florida, and Arkansas!" 


  • NSES Standards:

Young children begin their study of matter by examining and qualitatively describing objects and their behavior. The important but abstract ideas of science, such as atomic structure of matter and the conservation of energy, all begin with observing and keeping track of the way the world behaves. When carefully observed, described, and measured, the properties of objects, changes in properties over time, and the changes that occur when materials interact provide the necessary precursors to the later introduction of more abstract ideas in the upper grade levels.

Students are familiar with the change of state between water and ice, but the idea of liquids having a set of properties is more nebulous and requires more instructional effort than working with solids. Most students will have difficulty with the generalization that many substances can exist as either a liquid or a solid. K-4 students do not understand that water exists as a gas when it boils or evaporates; they are more likely to think that water disappears or goes into the sky. Despite that limitation, students can conduct simple investigations with heating and evaporation that develop inquiry skills and familiarize them with the phenomena.

PROPERTIES OF OBJECTS AND MATERIALS                                                         

Objects have many observable properties, including size, weight, shape, color, temperature, and the ability to react with other substances. Those properties can be measured using tools, such as rulers, balances, and thermometers.

Objects are made of one or more materials, such as paper, wood, and metal. Objects can be described by the properties of the materials from which they are made, and those properties can be used to separate or sort a group of objects or materials.

Materials can exist in different states-solid, liquid, and gas. Some common materials, such as water, can be changed from one state to another by heating or cooling.


  • AAAS Atlas:

Water can be a liquid or a solid and can go back and forth from one form to the other.  If water is turned into ice and then the ice is allowed to melt, the amount of water is the same as it was before freezing (Structure of Matter: States of Matter, p. 59).

When liquid water disappears, it turns into a gas (vapor) in the air and can reappear as a liquid when cooled, or a solid if cooled below the freezing point of water (Structure of Matter: States of Matter, p. 59).

Air is a substance that surrounds us and takes up space (Structure of Matter: States of Matter, p. 59).

Heating and cooling cause changes in the properties of materials (Structure of Matter: States of Matter, p. 59).

Things can done to materials to change some of their properties, but not all materials respond the same way to what is done to them (Structure of Matter: States of Matter, p. 59).

Objects can be described in terms of the materials they are made of (clay, cloth, paper, etc.) and their physical properties (color, size, shape, weight, texture, flexibility, etc) (Structure of Matter: Chemical Reactions, p. 61).

Many kinds of changes occur faster under hotter conditions (Structure of Matter: Chemical Reactions, p. 61).


  • Benchmarks of Science Literacy

The study of materials should continue and become more systematic and quantitative. Students should design and build objects that require different properties of materials. They should write clear descriptions of their designs and experiments, present their findings whenever possible in tables and graphs (designed by the students, not the teacher), and enter their data and results in a computer database.

Objects and materials can be described by more sophisticated properties-conduction of heat and electricity, buoyancy, response to magnets, solubility, and transparency. Students should measure, estimate, and calculate sizes, capacities, and weights. If young children can't feel the weight of something, they may believe it to have no weight at all. Many experiences of weighing (if possible on increasingly sensitive balances)-including weighing piles of small things and dividing to find the weight of each-will help. It is not obvious to elementary students that wholes weigh the same as the sum of their parts. That idea is preliminary to, but far short of, the conservation principle to be learned later that weight doesn't change in spite of striking changes in other properties as long as all the parts (including invisible gases) are accounted for.

With magnifiers, students should inspect substances composed of large collections of particles, such as salt and talcum powder, to discover the unexpected details at smaller scales. They should also observe and describe the behavior of large collections of pieces-powders, marbles, sugar cubes, or wooden blocks (which can, for example, be "poured" out of a container) and consider that the collections may have new properties that the pieces do not.

Heating and cooling can cause changes in the properties of materials, but not all materials respond the same way to being heated and cooled. 4D/E1*                                                                               

Many kinds of changes occur faster under hotter conditions. 4D/E1b                               - All materials have certain physical properties, such as strength, hardness, flexibility, durability, resistance to water and fire, and ease of conducting heat. 4D/E6** (SFAA)


NAEP (optional)

- Matter has physical and chemical properties. Physical properties common to all matter as well as those physical properties unique to solids, liquids, and gases are included in the framework, as are chemical properties. All objects and substances in the natural world are composed of matter. Matter has two fundamental properties: it takes up space and it has inertia; that is, it changes motion only when under the influence of a nonzero net force (grade 4).  (NAEP - pg. 26)

- Matter exists in several different physical states, each of which has unique properties (grade 4). Three of the most commonly encountered states are solids, liquids, and gases. Shape and compressibility are examples of properties that distinguish solids, liquids, and gases (grade 4). (NAEP - p. 27)                                                                                               

- The particulate model of matter can be used to explain and predict the properties of states of matter, such as why ice is harder than liquid water and why ice (once formed) has a shape independent of its container while liquid water takes the shape of whatever container it is in (grade 4). (NAEP - p. 27)                                                                                                         

- Matter can undergo a variety of changes. Changes are physical if the relationships between the molecules of the material are changed, such as from a solid to a liquid or from a liquid to a gas (grade 4). (NAEP - pg. 28)

Common Core Standards

Determine the meaning of general academic and domain-specific words or phrases in a text relevant to a grade 4 topic or subject area. (Grade 4: Reading for Informational Texts #4)

Interpret information presented visually, orally, or quantitatively (e.g., in charts, graphs, diagrams,time lines, animations, or interactive elements on Web pages) and explain how the information contributes to an understanding of the text in which it appears. (Grade 4: Reading for Informational Texts #7)

Produce clear and coherent writing in which the development and organization are appropriate to task, purpose, and audience. (Grade 4: Writing Standards #4)



Student Misconceptions 

Students of all ages show a wide range of beliefs about the nature and behavior or particles.  They lack an appreciation of the very small size of particles; believe there must be something in the space between particles; have difficulty in appreciating the intrinsic motion of particles in solids, liquids, and gases; and have problems in conceptualizing forces between particles.  Despite these difficulties, there is some evidence that carefully designed instruction carried out over a long period of time may help middle-school students develop correct ideas about particles. Source


Framework '97 Vignette, p. 3-29    SEE BELOW

This activity engages children in learning about changes of state as well as laying an appropriate foundation for understanding the particulate nature of matter. The National Science Education Standards include the study of water in the early grades because of the importance of the water cycle, and all children, regardless of their economic or cultural background, have had experiences with it. Later, they will apply what they have learned to other materials that are not so familiar.

Students in Ms. S's class investigate solid and liquid water. On a snowy day in January the students, bundled up and armed with plastic jars with their lids, traipse outside and fill their bottles with snow. They then file back into the classroom and place their jars on the counter. After removing mittens, boots, and snowsuits, they begin to record observations about their jars.

After a while, when the snow is melted, the students compare their bottles. They are surprised to discover that some jars contain less water than the others. Ms. S asks, "How could this be, if all of the jars were full of snow, and the lids were tightly screwed on?" A lively discussion ensues about what "full" means. They come to understand that they had used a variety of methods to collect their snow - that some students had packed their snow in the jar while others had gath- ered fluffy snow and that this could make a difference in their results. As a class, they decide on one method of determining "full" and repeat their excur- sion the next day.

This time, when the snow melts, the water remaining in the jars is more or less at the same level in all of the students' jars, but they notice that the water level seems to be lower than the level of snow they had origi- nally. They are puzzled by this and discuss ways to determine why there was a difference. They decide that by marking their jars with a permanent marker or rubber bands they can tell exactly where the snow and water levels are and measure the difference. In response to the questions about the lid being on, they also leave identical jars with the same amount of snow, overnight, but one with the lid off and the other on.

They find out that more water disappears with the lid off, but there is still less water in the jar than the amount of snow they began with. Leaving the "Where did the water in the open jars go?" question for another time, Ms. S. asks the students why there was less water than snow in the closed jars and how they might investigate that. They wonder if there is air in the snow and design further explorations to determine this.

The students collect snow under different environmental conditions. They investigate questions such as "Is the amount of water in light fluffy snow the same as in heavy snow?" and "Do equal weights of snow yield equal weights of water?"

Source: Physical Science On Location K-4 SciMathMN Minnesota K-12 Science  

Framework '97 Vignette, p. 3-29


Instructional Notes 

Suggested Labs and Activities

Design several stations, each of which demonstrates a state of matter (e.g., water table, balloon and fan table, sand and block table).  Source: Massachusetts Science and Technology/Engineering Curriculum Framework, October 2006, p. 64

Connected to Benchmark:  

Avogadro's Bubbly Adventure! Did you know that gases can be dissolved in liquids? Learn how it works in this activity. (Source: ACS - Chemistry for Life

Connected to Benchmark:

A State Debate Is shaving cream a solid, a liquid, a gas? (Source: ACS - Chemistry for Life

Connected to Benchmark:

Heat - Energy Extraordinaire! See how the power of heat energy makes molecules move faster. (Source: ACS - Chemistry for Life

Connected to Benchmark:

Full of Hot Air! What happens when air is heated? Find out in this activity. (Source: ACS - Chemistry for Life

Connected to Benchmark:

Changes in Matter How can you force a physical change in matter? Make some mystery matter and do experiments with it. Based on your observations, make conclusion about the state of your matter.

Connected to Benchmark:

What causes frost to form on the outside of a cold container? In this activity, students will see that the liquid water can change state again and freeze to become ice.

Connected to Benchmark:

Ice Race Break up your class into small groups or partners and give each group a plastic resealable bag and one ice cube. Then have groups race each other to see who can melt the ice cube first. Encourage groups to be creative in the way they add heat to their ice cubes. Students may use friction to help speed the melting, blow hot air on them, or put the bags in a sunny spot in the classroom. The first group whose ice cubes melt should raise their   hands. Use a stopwatch and take the opportunity to discuss elapsed time as a math extension. Source

Instructional suggestions/options

- Hands-on experiences are important for learning the different states of matter.

- Review safety precautions when using liquids and heating/cooling tools.  See the Safety in the Elementary Science Classroom guidelines.

Instructional Resources 

Additional resources

Kitchen Lab - Making Candy & Supercool Water Drop

Wonders of Our World - States of Matter: Experiments, Children's Literature References, Resource links

New Vocabulary 


Chemical Change = a change that produces a new substance

Gas = a state of matter in which the substance takes both the shape and the volume of its container

Liquid = a state of matter in which the substance has a definite volume but takes the shape of its container

Matter = the material, or "stuff", that everything is made of

Physical Change = a change from one form to another form without turning into a new substance

Solid = a sate of matter in which the substance has a definite shape and a definite volume

States of Matter = a form that matter can take-solid, liquid, or gas

Source: ScienceSaurus: A student handbook. (2005). Wilmington, MA: Great Source Education Group. Inc.

Technology Connections 

Gas, Liquid, Solid: Students click on gas, solid, or liquid to view the action of the particles up close.

Gases Around Us -  a stimulation to see the affect of heat and there is also a states of matter sorting activity.

Changing Matter - a stimulation

StudyJams! Solids, Liquids, & Gases: It includes a video, song, quiz, and vocabulary.

Cross Curricular Connections 

Students can write a short story from the perspective of a solid, liquid, or gas.

Students can create a collage of the different states of matter using pictures from magazines or online sources.

Students can create a skit or song to explain one or several of the states of matter to perform in front of younger students.


Assessment of Students

Ice Cubes in a Bag Assessment Probe. Source: Keely, P., Eberle, F., & Farrin, L. (2005). Uncovering student ideas in science: 25 formative assessment probes (vol. 1). Arlington, VA: National Science Teachers Association.

Is It Melting? Assessment Probe. Source: Keely, P., Eberle, F., & Farrin, L. (2005).       Uncovering student ideas in science: 25 formative assessment probes (vol. 1). Arlington, VA: National Science Teachers Association.

1.  Give an example of when these changes of matter happen:  (Level 2)

a. When matter changes from a solid to a liquid.

b. When matter changes from a liquid or gas to a solid.

c.  When matter changes from a liquid or solid to a gas.

2. Does liquid take up a different amount of space when it is put into a different container?  Explain your thinking.  (Level 2)

3.  What state of matter is rain? (Level 1)

            a. solid

            b. gas

            c. liquid

            d. plasma

4. What would happen if there was only one state of matter? (Level - 3)

5.  When water freezes or when water becomes a vapor is it still the substance: water?

Explain your thinking.  (Level 2/3)

Assessment of Teachers

1.  Getting matter to change its shaped has allowed us to create many large buildings, like the Sears Tower in Chicago.  How is this so? Source: Martin, R., Sexton, C. Franklin, T., & Gerlovich, J. (2005). Teaching science for all children: An inquiry approach. New York: Pearson Education, Inc.

2.  Why can't you put a round peg in a square hole? Source: Martin, R., Sexton, C. Franklin, T., & Gerlovich, J. (2005). Teaching science for all children: An inquiry approach. New York: Pearson Education, Inc.

3.  When water freezes or when water becomes a vapor is it still the substance: water?

Explain your thinking.  (Level 2/3)


Struggling Learners 

Struggling and At-Risk

Working in pairs to record observations helps students understand the concept of states of matter. Participating in a demonstration facilitates the understanding of an abstract concept. Have students stand up by their desks. Tell them they represent water molecules transitioning through different states of matter. Explain that when you call out a state of matter, you want them to move like the molecules at that state. Call out a state of matter, such as "SOLID." Students should walk very slowly around the room. Call out "FIRE UP........LIQUID." Students should begin to walk more quickly around the room. Call out "FIRE UP.......GAS." Students should walk even faster around the room. Call out "COOL DOWN......LIQUID." Students should walk a bit slower. Call out "COOL DOWN......SOLID." Students should walk very slowly.


English Language Learners 

General guidelines include...

Emphasize visual literacy - Regardless of linguistic background, people around the world can interpret mathematical equations and musical scores. In addition, they can also interpret pictures, and with minimal linguistic skills, can interpret charts and graphs. Visual literacy, or the ability to evaluate, apply, or create conceptual visual representation, is relatively independent of language, and is therefore invaluable to learning science and English simultaneously.

Hand-on activities - Kinesthetic learning events provide an excellent learning environment for English language learners.

Clear, procedural steps - The science laboratory can be a confusing and potentially dangerous setting for English language learners. Present procedures clearly using flow charts, pictures, and outlines.

Model laboratory activities - Demonstrate activities in front of class to ensure that English language learners can see the procedures before engaging in an activity.

Pictorial guide - Provide a visual reference to glassware and other materials used in experiments and activities. Review safety symbols and post them in the room and in the lab handout.


Extending the Learning 

Advanced learners can analyze the periodic table, and classify the elements as solids or gases.

Introduce the students to chemical nomenclature.  Provide practice time for balancing equations.


Incorporate different cultural celebration items such as food and liquids when sharing states of matter examples.

Special Education 

Working in pairs to record observations helps students understand the concept of states of matter. Participating in a demonstration facilitates the understanding of an abstract concept.


Classroom Observation 


Administrators should look for teachers to provide students with hands-on opportunities to explore the states of matter.  Administrators should make sure teachers are ensuring students are using the tools and materials accurately and safely.



What depth should students be able to describe this concept

At this level students are not expected to explain what is occurring at a particle level.