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

 

Science/Strand IV
Content Standard 2
All students will investigate, describe, and analyze ways in which matter changes; describe how living things and human technology change matter and transform energy; explain how visible changes in matter are related to atoms and molecules; and how changes in matter are related to changes in energy. (Changes in Matter)

 

Science/Strand IV/Content Standard 2
Middle School

 

Science/Strand IV/Content Standard 2/Middle School
Benchmark 3
Explain physical changes in terms of the arrangement and motion of atoms and molecules.

Benchmark Clarification

It is important for students to understand that the substance does not change its chemical composition when it undergoes a physical change. It only changes the state of matter.

As a substance undergoes a physical change, for example, when water changes from a solid to a liquid or from a liquid to a gas, the motion of the particles (atoms and/or molecules) increases and the space between particles increases also. There is nothing occupying the spaces between the particles.

Students will:

  • Identify and explain physical changes that occur when a substance changes size, shape, or state of matter (e.g., solid, liquid, gas)

Solids

Liquids

Gases

See Changes in state of matter, (SCI.IV.1.MS.4).

See Examples of Physical Changes of Matter, (SCI.IV.2.E.1) and (SCI.IV.2.MS.1).

See Speed of molecular motion, (SCI.IV.2.MS.1)

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

 

Science/Strand IV/Content Standard 2/Middle School/Benchmark 3
Key Concept
Molecular descriptions of states of matter

  • melting
  • freezing
  • evaporation
  • condensation
  • thermal expansion and contraction
  • moving faster, slower
  • vibrating
  • rotating
  • unrestricted motion
  • change in speed of molecular motion with change in temperature

 

Science/Strand IV/Content Standard 2/Middle School/Benchmark 3
Real World Context
Examples of physical changes of matter

 

Science/Strand IV/Content Standard 2/Middle School/Benchmark 3
Instructional Example

Benchmark Question: How does heat energy change the physical arrangement and motion of atoms and molecules?

Focus Question: How can bbŐs in a petri dish be manipulated to model the arrangement and motion of atoms/molecules when heat energy is added and removed?

The teacher should place about one hundred bbŐs in a petri dish with a lid and place the dish on the overhead projector. The teacher should roll the bbŐs, so they clump in one spot. The teacher should discuss with students that this represents the arrangement and motion of atoms/molecules in a solid.

The teacher should tell students that heat energy is being added as he or she gently wiggles the petri dish (the teacher should use enough movement to make the bbŐs move freely but not wildly). The teacher should discuss that this change represents a solid to liquid phase change.

Finally, the teacher will shake the petri dish more rapidly while keeping the dish flat on the overhead projector. BbŐs should rapidly ricochet off the sides and off each other. The teacher should discuss with students that this represents more heat being added and a phase change from liquid to gas.

Reverse the process to show heat energy being removed.

Constructing: (SCI.I.1.MS.1).

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

 

Science/Strand IV/Content Standard 2/Middle School/Benchmark 3
Assessment Example

Using a Chinese checkerboard set in an open box, students should manipulate the set to demonstrate the phase changes from solid to liquid to gas. Students should explain how heat energy causes this process to occur. Ask them how they can tell heat energy is present.

Working in small groups, students will demonstrate the arrangement and motion of water molecules. During class discussion, students should describe each change of phase:

  • In a solid, marbles should be next to each other, remaining in their holes, in a regular pattern and slightly vibrating.
  • In a liquid, marbles should be rotating and vibrating throughout the checkerboard.
  • In a gas, marbles should be far apart with some marbles bouncing in the box, in constant movement.

(Give students rubric before activity.)

Scoring Rubric

Criteria

Apprentice

Basic

Meets

Exceeds

Accuracy of demonstration

Demonstrates movement without connection to phase changes.

Demonstrates one phase change for two states of matter with appropriate amounts of shaking.

Demonstrates two phase changes for three states of matter through appropriate amounts of shaking.

Demonstrates a complete understanding of the phase changes of the three states of matter through the heating and cooling process.

Accuracy of explanation

Explains the role of heat energy with significant errors.

Explains the role of heat energy in causing phase changes in two states of matter.

Explains the role of heat energy in causing phase changes in the three states of matter.

Explains the role of heat energy in causing phase changes in the three states of matter and through the heating and cooling process.

 

Science/Strand IV/Content Standard 2/Middle School/Benchmark 3
Resources

Webliography.
http://mtn.merit.edu/mcf/SCI.IV.2.MS.3.html

Hard as Ice. NEW DIMENSIONS UNIT.

http://www.BCMSC.k12.mi.us/

Heat/Energy. Bill Nye Video. Disney Educational. (800/295-5010).

Matter and Its Changes. OPERATION PHYSICS.