Science.3.6.B

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The student is expected to

describe and classify samples of matter as solids, liquids, and gases and demonstrate that solids have a definite shape and that liquids and gases take the shape of their container;

1666 TEKS header image

Knowledge and Skills Statement

Matter and energy. The student knows that matter has measurable physical properties that determine how matter is identified, classified, changed, and used.

One common misconception is that any substance that can be poured is a liquid. If the particles of a solid are sufficiently small, they can be poured out of a container, like rice from a cup into a bowl. Each grain of rice is a solid, but collectively, they can be poured. 

In grade 3, the concept of categorizing solids, liquids and gasses is addressed only through the observable physical properties that students have studied so far. Students may explore whether the substance takes the shape of its container or has a definite volume, but they do not yet have the background to be able to describe what is happening to the atoms within the substance. In grade 5, students will describe particle behavior in solids, liquids, and gasses using images similar to the one below.

Three boxes labeled solid, liquid and gas. Solid box has tightly packed circles in an organized arrangement of rows and columns. Liquid box has circles without an organized arrangement and found in the lower part of the box. Gas box has circles without an arrangement spaced out in all areas of the box.
Image Source: https://commons.wikimedia.org/wiki/File:Solids_liquids_and_gases_-_particle_model.jpg

In middle school, students will be introduced to the concept of atoms as the building blocks of matter. They will build upon their learning about particles in grade 5 and describe states of matter based on the types, interactions, and motion of the particles within a substance. 

the state of matter where particles are far apart and moving quickly, bouncing off each other and their container; have a specific mass but because the particles have so much energy, they expand to fill all available space 

the state of matter that has a specific mass and volume; takes the shape of its container; particles are loosely arranged, flow around, and bounce off each other

substance that occupies space, has mass, and is composed of microscopic particles

observable characteristic of matter that can be used to identify particular materials

the state of matter that has a specific mass and volume; maintains its shape; particles are packed together tightly, vibrating in place 

Research

Keeley, Page. 2018. “Formative Assessment Probes: Uncovering Representations of the Water Cycle.” Science and Children 55, no. 5 (January 2018): 18-19.
http://www.jstor.org/stable/44709896. 

Summary: 3rd-grade students should know that solids and liquids exist and how to tell them apart. Many students are taught that solids keep their shape and liquids take the shape of their container, but these descriptions can cause misconceptions. Students often believe that solids are hard and cannot be soft. In this article, the teacher has students determine if an object is a solid or a liquid using its properties. Students make their claims about whether an object is solid and defend their claims using evidence. The other students do not give their opinion at first but just listen. Teachers listen for misunderstandings (such as flour being called a liquid because it is soft and pourable). These claims can be added to a chart for the class to discuss. It was obvious that most of the misconceptions were about solids that were soft, flexible, and stretchy. Students should then be allowed to observe things like flour to see that it is a material made up of many small solids. The teacher can then use the claims chart to assess student understanding.