Science
Strand IV
Use Scientific Knowledge from the Physical Sciences in Real-World Contexts

 

Science/Strand IV
Content Standard 1
All students will measure and describe the things around us; explain what the world around us is made of; identify and describe forms of energy; and explain how electricity and magnetism interact with matter (Matter and Energy)

 

Science/Strand IV/Content Standard 1
Middle School

 

Science/Strand IV/Content Standard 1/Middle School
Benchmark 4
Describe the arrangement and motion of molecules in solids, liquids, and gases. (SCI.IV.1.MS.4).

Benchmark Clarification

Students tend to assume that the molecules of a substance have the same properties as the substance itself. Students may incorrectly say, “The ice molecules are cold and hard. As the molecules heat up, they melt and turn to liquid.”

Students should correctly describe the state of matter based on the motion and arrangement of molecules as they interact with energy. There is nothing occupying the spaces between the molecules. The state of matter can be altered by a loss or gain of heat energy. Students should know that “phases of matter” is a synonym for “states of matter.”

Students will:

  • Describe correctly the arrangement and motion of molecules in states of matter:

See Molecular explanations of changes of state, (SCI.IV.2.MS.4).

Key Concept / Real World Context / Instructional Example / Assessment Example / Resources

 

Science/Strand IV/Content Standard 1/Middle School/Benchmark 4
Key Concept
Arrangement:

  • regular pattern
  • random

Distance between molecules:

  • closely packed
  • separated

Molecular motion:

  • vibrating
  • bumping together
  • moving freely

 

Science/Strand IV/Content Standard 1/Middle School/Benchmark 4
Real World Context
Common solids, liquids, and gases such as those listed above

 

Science/Strand IV/Content Standard 1/Middle School/Benchmark 4
Instructional Example

Benchmark Question: How are molecules arranged in matter?

Focus Question: What is the molecular motion and arrangement of the molecules in the states of matter: solid, liquid, and gas?

Students will observe models of molecular motion in solids, liquids, and gases. The teacher will demonstrate each state of matter and discuss the motion and arrangement of molecules with the class.

For a gas, the teacher will pour peppermint extract into a petri dish placed on the overhead projector. Note the time it takes for everyone in class to notice the smell.

For a solid, the teacher will pre-make a petri dish with clear, thick gelatin*. During the demonstration, the teacher will drop dark food coloring around the inside wall of the dish. Note the time it takes to evenly color the gelatin.

For a liquid, the teacher will place a water-filled petri dish on the overhead projector and drop food coloring into the water. Note the time it takes to color the water throughout.

Students will record their observations on data tables during the demonstration. As a class, students will compare the rate of movement to the molecular motion in different states of matter and discuss real-world observations (e.g., room fresheners, scratch and sniff magazine advertisements).

Alternative activity: Students may demonstrate solids, liquids, and gases by using their bodies as molecules. In a solid, students should be shoulder-to-shoulder and slightly vibrating. In a liquid, students must be arm-to-arm, vibrating, and moving randomly but close together. In a gas, students should take on the shape of the room by moving in straight lines until they bounce off someone or something.

Extension: Students may design an experiment to test the effects of temperature by using cold and warm water.

*Note: Gelatin is a suspension/mixture called a colloid, but it can be used in this demonstration to exhibit properties that are similar to a solid.

Constructing: (SCI.I.1.MS.1), (SCI.I.1.MS.2), (SCI.I.1.MS.3), (SCI.I.1.MS.4), (SCI.I.1.MS.6).

Reflecting: (SCI.II.1.MS.3).

 

Science/Strand IV/Content Standard 1/Middle School/Benchmark 4
Assessment Example

Students will respond to the following prompt by writing a short story

It is a hot summer day; you are an ice cube left in a glass. Identify the phases that you experience. Include your molecular motion and arrangement of molecules during each phase.

(Give students rubric before activity.)

Scoring Rubric

Criteria

Apprentice

Basic

Meets

Exceeds

Correctness of identification

Identifies few or none of the states of matter correctly.

Identifies some of the states of matter correctly.

Identifies most of the states of matter correctly.

Identifies all of the states of matter correctly.

Accuracy of description

Provides few or no correct descriptions of molecular motion and many misunderstandings of molecular motion.

Provides some correct descriptions of molecular motion and shows a few misunderstandings of molecular motion.

Provides many correct descriptions of molecular motion and shows no misunderstandings of molecular motion.

Provides all correct descriptions of molecular motion, shows no misunderstandings, and includes additional real-world examples.

Correctness of arrangement

Describes few or none of the molecular arrangements correctly.

Describes some of the molecular arrangements correctly.

Describes all of the molecular arrangements correctly.

Describes all of the molecular arrangements correctly and includes the terms melting, evaporating, and condensing.

 

Science/Strand IV/Content Standard 1/Middle School/Benchmark 4
Resources

Cooper, Christopher. Matter. Dorling Kindersley, 1992.

Hann, Judith. How Science Works. Reader’s Digest Association, 1991.

Matter & Molecules for Middle School. NEW DIMENSIONS UNIT.
http://www.BCMSC.k12.mi.us/