Lesson Plan

Separation of a Mixture

  • Grade Levels
    8th Grade
  • Related Academic Standards
  • Assessment Anchors
  • Eligible Content
  • Big Ideas
    • A technological world requires that humans develop capabilities to solve technological challenges and improve products for the way we live.
    • Each area of technology has a set of characteristics that separates it from others; however, many areas overlap in order to meet human needs and wants.
    • Technological design is a creative process that anyone can do which may result in new inventions and innovations.
    • Technological literacy is the ability to use, assess and manage technology around us.
    • Technology is created, used and modified by humans.
  • Concepts
    • A technological design & problem solving process changes ideas into a final product or system.
    • Bio-related technologies are the processes of using biological mater to make or modify products.
    • Bio-related technologies are the processes of using biological organisms to make or modify products.
    • Communication is the process of composing, sending, and receiving messages through technology.
    • Communication is the process of composing, sending, and receiving messages using technological devices.
    • Construction is the process of turning materials into useful structures.
    • Construction is the process of turning raw materials into useful structures.
    • Decisions about the use of products and systems can result in expected and unexpected consequences.
    • Energy and power technologies are the processes of converting energy sources into useful power.
    • Energy and power technologies use processes to convert energy into power.
    • In a technological world, inventions and innovations must be carefully assessed by individuals and society as a whole.
    • Innovation is the process of improving an existing product, process, or system.
    • Innovation is the process of modifying an existing product, process, or system to improve it.
    • Invention is a process of creating new products, processes, or systems.
    • Invention is a process of turning ideas and imagination into new products, processes, or systems.
    • Inventions and innovations must be carefully assessed by individuals and society.
    • Manufacturing is the process of turning materials into useful products.
    • Manufacturing is the process of turning raw materials into useful products.
    • People select, create, and use science and technology and are limited by constraints (e.g. social and physical).
    • People select, create, and use technology.
    • Safety is a preeminent concern for all technological development and use.
    • Safety is one of the most important concerns for all technological development and use.
    • Science and technology are interconnected.
    • Technological design & problem solving follows many steps.
    • Technological design & problem solving includes clearly communicated solutions.
    • Technological design & problem solving includes frequent checking.
    • Technological design & problem solving requires hands-on applications.
    • Technological literacy is a lifetime endeavor.
    • Technological literacy is necessary for a productive 21st century skilled workforce.
    • Technological literacy is necessary for a productive workforce.
    • Technological literacy is necessary for all citizens.
    • Technological literacy is required for all citizens in a democratic society for shared decision-making.
    • Technological literacy is the ability to understand, use, assess, design, and create technology.
    • Technological literacy is the ability to understand, use, assess, design, and produce technology (i.e. Invention & Innovation).
    • Technological literacy requires lifelong learning.
    • Technology and society impact each other.
    • Technology and society mutually impact each other.
    • The abilities required in a technological world include diagnosing, troubleshooting, analyzing and maintaining systems.
    • The abilities required in a technological world include understanding, fixing, and maintaining systems.
    • The goal of technology is to meet human needs and wants.
    • Transportation is the process of safely and efficiently moving people and products.
    • Understanding technological systems help us plan and control technological developments.
    • While science is the study of the natural world, technology is the study of the human designed world.
  • Competencies
    • Create a new product, process, or system.
    • Describe and demonstrate how to use technological design & problem solving.
    • Describe how science and technology work together.
    • Design and develop the ability to create and send messages using technological devices.
    • Design and develop the ability to safely and effectively use tools and materials to build structures.
    • Design and develop the ability to safely and effectively use tools and materials to convert energy into power.
    • Design and develop the ability to safely and effectively use tools and materials to create bio-related products and systems using technology.
    • Design and develop the ability to safely and effectively use tools and materials to create vehicles that transport people and products.
    • Design and develop the ability to safely and effectively use tools and materials to manufacture products.
    • Design and produce solutions to technological problems.

Objectives

In this lesson, students will have an opportunity to synthesize the previous lesson’s content in a practical lab setting. They will use their knowledge of physical properties and mixtures to separate a heterogeneous mixture. Students will:

  • differentiate between a pure substance and a mixture.

  • create a lab procedure that enables them to separate a suspension based on the physical properties of its components.

  • recognize that magnetism is a physical property of iron.

  • recognize that solubility in water (at a given temperature) is a physical property of sodium chloride.

  • recognize that sand does not dissolve in water, differentiating it from sodium chloride.

  • perform a separation lab, following proper instructions and safety protocol.

  • recognize that salt water is a solution and can be separated physically.

Essential Questions

Vocabulary

  • Element: Pure substance consisting of one type of atom.

  • Compound: Pure substance consisting of two or more different atoms.

  • Mixture: Two or more different substances not chemically combined.

  • Colloid: A heterogeneous mixture that exhibits the Tyndall effect.

  • Magnetism: The force of attraction or repulsion between various substances, especially those made of iron and certain other metals; ultimately it is due to the motion of electric charges.

  • Suspension: A heterogeneous mixture that has particles large enough to settle out.

  • Solution: A homogenous mixture in which the particles are very small.

  • Homogeneous Mixture: A mixture with a uniform composition.

  • Heterogeneous Mixture: A mixture with a non-uniform composition.

  • Element Symbol: An abbreviation for an element’s name found on the periodic table.

  • Compound Formula: Represents the combination of two or more elements in fixed proportions. Subscripts designate the number of atoms of each element.

Duration

90 minutes/2 class periods

Prerequisite Skills

Prerequisite Skills haven't been entered into the lesson plan.

Materials

  • goggles

  • hot plate

  • tweezers

  • magnet

  • large tongs

  • oven mitt, hot pad, or protective glove

  • water

  • graduated cylinder (10-25 mL)

  • weigh boats (4)

  • 100 mL Erlenmeyer flask

  • funnel

  • filter paper

  • evaporating dish with mixture (75-150 grams)

  • glass stir rod

  • Separation of a Mixture–Student activity sheet (S-8-5-3_Separation of a Mixture Student.doc)

  • Separation of a Mixture–Teacher activity sheet (S-8-5-3_Separation of a Mixture Teacher.doc)

Related Unit and Lesson Plans

Related Materials & Resources

The possible inclusion of commercial websites below is not an implied endorsement of their products, which are not free, and are not required for this lesson plan.

  • goggles

  • hot plate

  • tweezers

  • magnet

  • large tongs

  • oven mitt, hot pad, or protective glove

  • water

  • graduated cylinder (10-25 mL)

  • weigh boats (4)

  • 100 mL Erlenmeyer flask

  • funnel

  • filter paper

  • evaporating dish with mixture (75-150 grams)

  • glass stir rod

  • Separation of a Mixture–Student activity sheet (S-8-5-3_Separation of a Mixture Student.doc)

  • Separation of a Mixture–Teacher activity sheet (S-8-5-3_Separation of a Mixture Teacher.doc)

Formative Assessment

  • View
    • The formative assessment for this lesson occurs when students are answering questions posed in the various lab sections. If students cannot identify the mixture as a suspension, remind them of the last lesson, citing examples of suspensions. Ask them, “Does the mixture in front of you settle out over time? Is it easy to see that it is a combination of more than one thing?”

    • While students are developing a proper lab procedure, move around the room, asking questions such as:

    • You have four components. Which one is soluble in water?”

    • Which component would be the easiest to remove based on size?”

    • What technique would you use to remove salt from salt water?”

    • Which metal is magnetic, iron or copper?”

    • Students also have follow-up questions at the conclusion of the lab. Monitor their responses and correct misunderstandings, if necessary.

Suggested Instructional Supports

  • View
    Scaffolding, Explicit Instruction
    W:

    Students use the physical properties of pure substances to separate a mixture. They complete a flowchart before the start of the lab so that they will feel confident in separating the mixture. Students will be made aware that they will be graded on their lab performance and summary lab questions.

    H:

    Students examine an unknown mixture in teams of two to four before the start of the lab. They are given an opportunity to investigate and hypothesize their own separation techniques.

    E:

    The lab itself provides a hands-on experience that supports the material covered earlier in the unit. The prelab investigation also provides a creative experience for high-level students.

    R:

    The lab revisits the material taught earlier in the unit. Students are able to use, rather than read about, boiling point and magnetism in the lab. In addition to the practical application of separation techniques, there are analytical questions at the end of the lab.

    E:

    Throughout the lab, move from lab station to lab station, asking in-depth questions regarding the lab. Students will complete the data table, prelab worksheet, and summary questions.

    T:

    Students who are ready will have an opportunity to develop the separation techniques before the lab begins. For students who need more support, the class will determine the final lab procedure before it begins.

    O:

    The prelab activity functions as a bridge between teacher-guided instruction and student independence. The dialogue between the teacher and students during the lab serves to develop conceptual understanding.

Instructional Procedures

  • View
    l3-01safetynote.PNG

    Conduct a brief review of the past material by asking the class the following questions:

    • How would you be able to differentiate between a suspension and a colloid?”

    (Colloids exhibit the Tyndall effect, whereas suspensions do not. Suspensions often settle out, whereas colloids do not.)

    • How would you be able to differentiate between a solution and a colloid?”

    (Colloids have medium-sized particles and their particles scatter light. Solutions have very small particles, cannot be separated through basic filtration, and their particles do not scatter light.)

    • List five physical properties…”

      (Answers may vary. Examples include viscosity, density, conductivity, magnetism, boiling/melting/freezing point, thermal expansion/contraction, malleability, ductility, surface tension, volatility, etc.)

    Lab Activity

    Tell students, “Today, you are going to demonstrate your knowledge of physical properties and mixtures by completing a lab activity. Each team (lab groups of two to four students) will be given the same substance. Your task is to separate the substance into its original components and in their original state. The substance is made from sand, copper shot (or copper pieces), iron filings, and salt.”

    Have students proceed to the lab stations in teams of two to four. At each lab station, provide the equipment listed in the Materials section. Give each student the Separation of a Mixture activity sheet (S-8-5-3_Separation of a Mixture Student.doc).

    Tell students, “You will be given 15 minutes to examine the mystery substance, look over the equipment provided to you, and fill out Part I of your Separation of a Mixture lab worksheet. As a class, discuss the answers to Part I. Use the Separation of a Mixture–Teacher activity sheet for answers (S-8-5-3_Separation of a Mixture Teacher.doc). You can have students return to their seats or stay at their lab stations. They should all be aware that the mystery substance is a heterogeneous mixture that is classified as a suspension. When addressing the last question in Part I, say, “Which physical properties would help you separate this mixture? In what order should the separation techniques be done?”

    Then direct students’ attention to Part II of the lab handout. In this section, the teams design their own procedure for separating the mixture. The flowchart will give them an idea of the order. After 10 minutes, write and discuss the correct answers on the board.

     l3-02flowchart.PNG

    Once students understand the procedure, demonstrate proper lab protocol.

    1. Obtain a small evaporating dish of the mixture.

    2. Using tweezers, pick the copper shot from the mixture. Transfer it to an empty weigh boat.

    3. Use a magnet to attract the iron filings. Sort through the mixture’s layers, as there are filings at the bottom as well. This may irritate your hands, so gloves will be available. Scrape the filings off the magnet and into a separate weight boat.

    4. To separate the sand from the salt, you will need to add 10–25 mL of water to the evaporating dish. Use glass stir rods to dissolve all of the salt. Set to the side.

    5. Using filter paper, make a funnel shape like the one shown below:


    l3-03filters.PNG
    1. Put the funnel-shaped filter paper inside a funnel and place the funnel on an Erlenmeyer flask.

    2. Pour the sand, water, and salt mixture through the funnel. Wait until all the water has gone through the filter and into the flask.

    3. Remove the sand and filter paper from the flask and lay them on a paper towel to dry.

    4. Pour the salt water into an evaporating dish and place it on a hot plate (on medium). Watch closely. The water will boil off, leaving the salt behind. Turn off the hot plate.

    5. Remove the evaporating dish with tongs or a hot pad. Be careful as the dish is hot.

    6. All glassware can be rinsed with water. Iron, copper, and sand can be recycled for the next class to use.

    Extension:

    • If you have covered phase changes, sublimation in particular, you can add ammonium chloride (NH4Cl) to the mixture. After students have removed the copper shot and the iron filings, they can set up a ring stand with a Bunsen burner underneath. They should place the evaporating dish on a clay triangle and heat the mixture until it smokes. The white smoke is the ammonium chloride leaving the mixture. Students should use a glass rod to stir the mixture every once in a while. Once the smoking stops, the sublimation of NH4Cl is complete. Let the dish cool until it is safe to be handled. The remaining separation techniques are the same.


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DRAFT 11/18/2010
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