Grade 2. In Matter, students are introduced to the 3 states of matter—solids, liquids, and gases. They explore the differing arrangement of molecules and observe and record different characteristics of each state. Students develop an understanding that not all solids or liquids are the same, and that solids can be malleable and liquids can vary in thickness and fluidity, or viscosity. Students then build on their conception of states of matter by creating mixtures. They observe the outcome of combining solids with solids and solids with liquids.
Students observe 2 types of matter spread out evenly within another type of matter and distinguish the difference between a mixture and a solution. They explore how temperature can affect how completely some types of matter dissolve in water. Students make mixtures and then use different methods to separate them. First, they physically separate 2 solids by picking rice grains out of sand grains. They use a filter to separate water from a humus and water mixture, and investigate how the particles of humus cannot fit through the same space as the water. Then, they separate a saltwater solution by using evaporation.
Students are assessed through a culminating activity during which they create a mixture and determine the best way to separate (filtration or evaporation) the matter within by applying the methods they learned in this unit.
The Matter unit addresses the following standards:
Next Generation Science Standards®
Disciplinary Core Ideas
- PS1.A: Structure and Properties of Matter
- PS1.B: Chemical Reactions
- Analyzing and Interpreting Data
- Constructing Explanations and Designing Solutions
- Engaging in Argument from Evidence
- Planning and Carrying Out Investigations
- Science Models, Laws, Mechanisms, and Theories/Explain Natural Phenomena
- Cause and Effect
- Energy and Matter
Common Core State Standards
This unit offers several ways to assess students, including a pre- and a post-unit assessment opportunity. Teachers can also use class discussions and charts to assess each lesson. Student activity sheets and science notebook entries—including drawings, writings, and dictated statements—can be used to gauge individual understanding of objectives and key vocabulary throughout the unit. The Assessment Observation Sheets supplied with each lesson help teachers document and measure students’ progress and knowledge using informal assessment. A general rubric is provided to help teachers evaluate individual students at any point in the unit. The rubric provides a progression of skills and understanding that covers exploration, vocabulary, concept building, and notebook entries. Finally, a summative assessment gives students the opportunity to demonstrate unit-specific content knowledge by responding to questions in a variety of formats.
Lesson 1: What’s the Matter?
Matter can be observed in 3 states: solid, liquid, and gas. This lesson begins with a pre-assessment to determine students’ prior knowledge of the states of matter in which water can be found. They observe and organize the different states of water. As they observe and record different characteristics of each state of matter, students make the connection between the states of matter and the differing arrangement of molecules in each state.
Lesson 2: Solids, Liquids, and Mixtures
By observing the varying behaviors of different solids and liquids, students conclude that their characteristics can also vary. They discover that solids can be malleable and that liquids can vary in thickness and fluidity, or viscosity. Students test viscosity of liquids by measuring the time it takes for a solid to move through them in a graduated cylinder. Students build on their understanding of states of matter by creating mixtures. They observe the outcome of combining solids with solids and solids with liquids.
Lesson 3: Mixers
Students examine combining substances more closely. By making firsthand observations, students distinguish the difference between a mixture and a solution. They also combine water and gelatin powder to form gelatin, a colloid. Students learn that some types of matter can dissolve in liquids, and they explore how temperature can affect how quickly some types of matter dissolve in water.
Lesson 4: Separation
Students make mixtures and use different methods to separate them. They use a filter to separate a humus and water mixture, and observe that the particles of humus cannot fit through the same space as the water. Students then discover that filters can’t separate all components of a mixture when they observe that the salt in a saltwater solution passes through the filter with the water. By pouring the saltwater solution onto a sponge, they are able to see the salt is separated from the water when it remains behind after the water in the solution evaporates.
Students discover that not all matter can be separated by physical means once it has been combined. This is reinforced with the gelatin colloid in the concluding activity, in which students try to separate the set gelatin into its original components. Through experimentation, students come to realize that the water and gelatin went through a chemical change and cannot be separated.
Lesson 5: Mix It Up and Break It Down
In this final lesson, students are challenged to separate mixtures that contain more than 1 type of matter by applying multiple separation methods. They are assessed in a culminating activity in which they create a mixture and determine the best way to separate the matter within using the methods they learned about in this unit.