Science/Strand IV/Content Standard 2/Elementary
Benchmark 2
Prepare mixtures and separate them into their component parts.

Benchmark Clarification

Physical change occurs when materials are mixed together. Differences in physical properties enable students to separate the mixture or solution.

Separation techniques:

  • Using a filter
  • Using a sieve
  • Using magnets
  • Floating vs. sinking
  • Evaporating


Students will:

  • Prepare a mixture of two or more materials.
  • Identify the physical properties of materials that determine appropriate separation techniques
  • Separate a prepared mixture or solution by choosing the appropriate separation techniques and tools

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


Science/Strand IV/Content Standard 2/Elementary/Benchmark 2
Key Concept

  • mixture
  • solution

Separation techniques (K-2):

  • filtration
  • using sieves
  • using magnets
  • floating vs. sinking

Dissolving soluble substances, evaporating (3-5):

  • using two liquids
  • using a solid and a liquid


  • filter paper
  • funnels
  • magnets
  • sieves
  • beakers
  • solar stills


Science/Strand IV/Content Standard 2/Elementary/Benchmark 2
Real World Context
Mixtures of various kinds:

  • salt and pepper
  • iron filings and sand
  • sand and sugar
  • rocks and wood chips
  • sand and gravel
  • sugar or salt solutions


Science/Strand IV/Content Standard 2/Elementary/Benchmark 2
Instructional Example

Benchmark Question: How are mixtures separated into their component parts?

Focus Question: What are the different strategies for separating mixtures?

In small groups, students will brainstorm types of mixtures (e.g., salt and pepper, sand and sugar, iron filings and sand, rocks and wood chips, sugar or salt solutions) and report their findings to the whole group. Using the students═ lists of mixtures, evaluate the mixtures and predict the appropriate methods to separate them into the original materials.

The teacher will provide the materials, so students can make their own mixtures. Students will weigh each material and record their measurements before preparing each mixture. Students will weigh each mixture and record their measurements in a data table with the following headings:

  • Mixture form
  • Mixture/Solution
  • Method of separation
  • Tools
  • Weight of original materials
  • Weight of mixture

Students will choose appropriate methods and tools (e.g., filter paper, funnels, magnets, sieves, beakers, solar stills). Students will experiment with ways to separate the mixtures into their original materials. Students will weigh their mixtures before separating them and will record their measurements. Students will compare the measurements of the original mixture to the combined weight of the original materials.

Constructing: (SCI.I.1.E.1), (SCI.I.1.E.2), (SCI.I.1.E.3), (SCI.I.1.E.5), (SCI.I.1.E.6).

Reflecting: (SCI.II.1.E.1).


Science/Strand IV/Content Standard 2/Elementary/Benchmark 2
Assessment Example

The teacher will prepare a variety of solutions and mixtures using water, salt, sugar, dirt, sand, gravel, leaves, iron filings, etc. Students will be asked to answer the question, ˝What is the best way to separate each mixture/solution?ţ Small groups will choose the appropriate method and tools to separate each solution or mixture. Students will use their chosen tools to separate the mixtures and solutions. They will evaluate the effectiveness of their choices of methods and tools.

Each student will record each mixture/solution, the chosen tools, and the chosen method of separation in his or her science journal. Each student will write conclusions that evaluate the effectiveness of the chosen tools and the chosen methods. The groups will present their evaluations to an audience.

(Give students rubric before activity.)

Scoring Rubric






Completeness of data table

Creates incomplete data table.

Creates incomplete data table.

Creates complete data table.

Creates complete data table.

Accuracy of evaluations

Provides many inaccurate evaluations.

Provides some inaccurate evaluations.

Provides a few inaccurate evaluations.

Provides accurate evaluations.


Science/Strand IV/Content Standard 2/Elementary/Benchmark 2


Cobb, Vicki. More Science Experiments You Can Eat. Harper, 1994.

Cobb, Vicki. Science Experiments You Can Eat. Harper, 1994.

Glover, David. Solids & Liquids. Kingfisher, 1994.