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 2
Describe common chemical changes in terms of properties of reactants and products.

Benchmark Clarification

It is important for students to understand that a chemical change begins with original substances called reactants. During a chemical change, a new substance with new properties is produced. This new substance is called the product. The mass remains constant, because a chemical reaction is a closed system and no matter is lost.

Students will:

  • Observe and describe that all chemical changes begin with original substances that are called reactants.

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

 

Science/Strand IV/Content Standard 2/Middle School/Benchmark 2
Key Concept
Common chemical changes:

  • burning
  • rusting iron
  • formation of sugars during photosynthesis
  • acid reacting with metal and other substances

Mass/weight remains constant in closed systems

 

Science/Strand IV/Content Standard 2/Middle School/Benchmark 2
Real World Context
Chemical changes:

  • burning
  • photosynthesis
  • digestion
  • corrosion
  • acid reactions
  • common household chemical reactions such as with alkaline drain cleaners

 

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

Benchmark Question: What happens to matter when it undergoes a chemical change?

Focus Question: What are the reactants and products when paper burns?

Students will work in small groups and brainstorm lists of different changes they have observed in matter. One student will cut paper into pieces and place the paper into an aluminum pie pan. The teacher should remind students that this is a physical change (SCI.IV.2.MS.1).

The students should carefully burn the paper in the pie pan. Each student will draw and describe the reactants involved in burning the paper. Reactants should include the sulfur on the match head, oxygen, and carbon (paper pieces). Each student will describe the chemical change and draw what they observed. Specifically, students should do the following:

  • Describe the reactants: paper and oxygen in the air
  • Identify the heat and light energy that are produced when the friction of striking the match on an abrasive surface ignites the sulfur on the match head and produces a chemical change
  • Describe that the heat energy from the burning match causes the paper and oxygen to combine and form the products of smoke, ash, carbon dioxide, and water vapor

Each student will create a table , which includes the drawing and observations of the following:

Drawings

Reactants (before burning)

  • paper (cellulose)
  • oxygen (invisible in air)                  

Reactants and Products

(during burning)

  • smoke
  • gases (CO2 and H2O)
  • light
  • heat (flame)
  • ashes form

Products (after burning)

  • ashes
  • gases (CO2 and H2O invisible in air)

Constructing: (SCI.I.1.MS.1), (SCI.I.1.MS.6).

Reflecting: (SCI.II.1.MS.5).

 

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

After students have experienced and discussed burning in terms of products and reactants (see Instructional Strategy), they will be ready to assess the burning of a candle. Working within a small group, students will observe a burning candle. Students will list and categorize the reactants (wax, O2, wick) and products (smoke, CO2, and H2O vapor) of the burning process.

The process of photosynthesis is related to a burning candle because they both involve an energy transfer utilizing reactants and producing products. Students will list the reactants and products of photosynthesis and (SCI.III.2.MS.3).

(Give students rubric before activity.)

Scoring Rubric

Criteria

Apprentice

Basic

Meets

Exceeds

Accuracy of identification- reactants

Identifies none of the reactants.

Identifies one of the reactants.

Identifies two reactants.

Identifies three reactants.

Accuracy of identification- products

Identifies none of the products.

Identifies one of the products.

Identifies two of the products.

Identifies three products.

 

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

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

Chemical Reactions/Phases of Matter. Bill Nye Video. Disney Educational (800/295-5010).

Chemistry That Applies. NEW DIRECTIONS UNIT.
http://www.BCMSC.k12.mi.us/

Off The Wall Science. AIMS.
http://wwws.aimsedu.org/aimscatalog/default.tpl