4.2.1.2 States of Matter

• 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.

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• 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).

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• 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)

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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)

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