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 3
Classify substances as elements, compounds, or mixtures and justify classifications in terms of atoms and molecules.

Benchmark Clarification

Matter consists of extremely small, invisible particles called atoms. Atoms cannot be broken down into their smaller parts during a physical change, or during a chemical reaction. They can be broken into smaller particles during nuclear reactions. All elements are made of one kind of atom. See Periodic Table of Elements.

Atoms may exist alone or be combined together. When two or more atoms join together, they form molecules. When different kinds of elements join together, they form compounds.

For example, oxygen exists as a molecule containing two oxygen atoms in the atmosphere. When three oxygen atoms join together, they form the molecule called ozone.

Water is a substance/ a compound made of hydrogen and oxygen atoms. Each water molecule is made of two atoms of hydrogen and one atom of oxygen.

These molecules/compounds do not break down into individual atoms/elements when they are heated or cooled during phase changes.

Molecules can be broken down into separate atoms or simpler molecules when exposed to electrical current or during a chemical reaction. Examples of chemical reactions include:

  • a reaction with acids
  • decomposition
  • burning (a chemical reaction with oxygen. .

When two or more elements and/or compounds are physically combined together, they are called a mixture. Mixtures can be physically separated into their original components.

Students will:

  • Classify substances as elements, compounds, or mixtures
  • Justify their classifications in terms of atoms and molecules.

See Molecular Structure of solids, liquids, and gases, (SCI.IV.1.MS.4).

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

 

Science/Strand IV/Content Standard 1/Middle School/Benchmark 3
Key Concept

  • element
  • compound
  • mixture
  • molecule
  • atom

 

Science/Strand IV/Content Standard 1/Middle School/Benchmark 3
Real World Context
Common substances such as those listed above, including:

Elements such as:

  • copper
  • coal
  • aluminum
  • graphite (carbon)
  • sulfur
  • helium
  • iron

Compounds such as:

  • water
  • chalk
  • salt
  • sugar
  • carbon dioxide

Mixtures such as:

  • soil and water
  • soil and Kool-Aid
  • Italian salad dressing
  • salt and pepper
  • milk
  • salt water
  • air

 

Science/Strand IV/Content Standard 1/Middle School/Benchmark 3
Instructional Example

Benchmark Question: How do we classify the things around us?

Focus Question: How are elements, compounds, and mixtures classified in terms of atoms and molecules?

Each student will construct at least one model of an element and one model of a compound by using broken toothpicks and raisins, colored mini-marshmallows, or gumdrops.

Students will work in small groups and create a concept map to classify elements, compounds, and mixtures in terms of atoms and molecules. They will glue and label the models they are creating onto the concept map.

Students will choose a single color item to represent one kind of atom. They will label this on the concept map as atom 1. They should repeat this step for atom 2 and atom 3. Then they should combine individual atoms (single color items) to form elements (all atoms the same color and property) and glue their element samples onto their concept maps and label them.

They should form compounds by attaching elements with toothpicks (toothpicks represent bonds) and glue these samples onto their concept maps and label them.

They should form mixtures by combining two or more elements and/or compounds (these are not bonded; do not use toothpicks) and glue these samples onto their concept maps and label them.

They should add definitions of terms and real-world examples for each element and compound.

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

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

 

Science/Strand IV/Content Standard 1/Middle School/Benchmark 3
Assessment Example

Students will create a chart, arranging at least nine items into the appropriate classification as an element, compound, or mixture. They should justify the classification in terms of atoms and molecules.

Possible items to choose from: Kool-Aid, water, salt, aluminum foil, salad dressing, copper wire, soil, chalk, air, salt water, milk, coal, graphite, helium, sulfur. The teacher will supply a list of ingredients for each of the items.

Note: Check Benchmark Clarification for proper classification.

(Give students rubric before activity.)

Scoring Rubric

Criteria

Apprentice

Basic

Meets

Exceeds

Completeness of chart

Creates a chart with few headings and some missing information.

Creates a complete chart with correct headings but some missing information.

Creates a complete and correct chart with proper headings.

Creates a complete and correct chart with proper headings and detailed explanations.

Correctness of identification

Identifies three or fewer items.

Identifies four to six items.

Identifies seven to eight items correctly and completely.

Identifies all nine items correctly and completely.

Correctness of justification

Justifies three or fewer items.

Justifies four to six items.

Justifies seven to eight items correctly and completely.

Justifies all nine items correctly and completely.

 

Science/Strand IV/Content Standard 1/Middle School/Benchmark 3
Resources

Webliography.
http://mtn.merit.edu/mcf/SCI.IV.1.MS.3.html

Edible Molecule. AIMS.
http://wwws.aimsedu.org/aimscatalog/default.tpl

Molecular Model Kits.

Water, Precious WaterŠThe Water Molecule. AIMS.
http://wwws.aimsedu.org/aimscatalog/default.tpl