Wooden sieves (photo on Pixabay)

Setting the Stage

Prior Skills and Knowledge:

To successfully participate in this Design & Build, students should be able to work with basic cutting and fastening tools and materials (e.g. masking tape, duct tape, packing tape, pipe cleaners). It is recommended that students participate in the What is soil made of? inquiry before doing this Design & Build challenge.

Context:

A sifter is a tool that separate particles of a substance by size. Since soil is a mixture of rock particles of different sizes, sometimes it is helpful to separate soils to use them for different purposes. It is easier to plant seeds and seedlings and to pull weeds in garden soil that has few stones. Building products, such as cement and grout, are created using combinations of soil ingredients. Cement, for example, is a combination of sand, gravel and Portland cement (a mixture of finely ground minerals and rocks).

Flour sifters
(Photo by Shliphmash via Wikimedia Commons)

Part of the design process is developing a design plan. A design plan integrates a variety of skills from different curriculum areas. For example, students need to communicate orally (with other members of the group) and in writing (writing down the steps of the plan). They need to use logical thinking skills to outline in order the steps they will take to create their prototype. They need to make thoughtful and purposeful decisions about the materials and fasteners they will need if they are building a product. They need to draw on their visual arts skills when sketching a prototype by hand or when using a digital program. A good design plan takes time to develop but helps all members of the group to know where they are going and how they will get there.

Students develop a design plan (e.g., steps in creating a prototype, decisions about tools and materials).

In this Design & Build challenge, students will design and build a soil sifter that can separate a soil mixture into at least three particle sizes.

Variety of tea bags
(Photo by Skitterphoto via Pexels)

This design and build could begin from:

  • Displaying examples of common strainers and sifters (e.g., flour sifter, strainer, colander, tea strainer, metal coffee filter, etc.). Discuss using questions such as:
    • “What do all of these items have in common? How are they different? Why are the differences important?”
    • “Who might use these tools and for what purpose?”
  • Exploring photos of tools that separate. Discuss using questions such as:
    • “What do these tools have in common? How are these tools different?”
    • “What types of materials do you think these tools separate? Are some better for separating one state of matter (e.g., solids) than others? Why do you think that?”

Design Criteria:

As a class, students brainstorm criteria that their prototype soil sifter must meet. Educators may choose to add other criteria that are curriculum-specific, such as using joiners/fasteners, measuring, using specific materials, measuring forces, etc.

Design criteria examples:

  • The sifter system must sort the soil into three portions based on relative particle sizes
  • The sifter must be constructed from the materials provided

Materials and Preparation (Click to Expand)

Materials:

  • Soil mixture – approximately 500 ml per group
  • Selection of colanders, small plastic baskets, screening, plastic mesh
  • Craft sticks
  • Straws
  • Fasteners (e.g. masking tape, duct tape, packing tape, pipe cleaners)
  • Scissors
  • Newspapers and/or plastic tablecloths

Preparation:

  • Collect the materials that students will use to construct the soil sifter system. The materials list above is only a suggested list.
  • Students could all be provided with the exact same materials and tools or students could choose their own materials.
  • Working with soils is messy. Consider collecting newspaper to cover tables or using plastic tablecloths to facilitate cleaning up after the Design and Build.

What To Do

Students develop Design & Build skills as they design, build and test a prototype soil sifter.

Students will follow the steps of the Design & Build process:

Making design on paper
(Photo via Pexels)

  • identify the problem to be solved/need to be met
  • brainstorm criteria that the prototype must meet
  • share their questions and ideas for a solution to the problem/need
  • discuss the advantages and disadvantages of each in order to select a potential solution to be tested
  • visualize what the solution might look like and make design sketches based on their visualizations
  • develop a design plan (e.g., identify the tasks or key steps involved in developing the solution, make decisions about tools and materials that will be needed, include labelled sketches)
  • build/develop the design idea based on their sketches and design plan
  • test their prototypes based on the design criteria
  • modify the prototype and retest it against the design criteria as necessary
  • reflect on their results and identify things that could be done to improve their prototypes

Assessment

Observe and document, using anecdotal comments, photos and/or video recordings, student’s ability to:

  • Work Collaboratively - students work collaboratively to complete a task and evaluate their group processes throughout the Design & Build process
  • Generate Ideas - students use idea generation strategies, such as brainstorming, to identify possible solutions as well as make decisions about the pros and cons of each solution
  • Communicate - communicate through writing and other means, design plans including 2D design sketches, key design steps/tasks, required materials and equipment/tools
  • Work Safely - use safe practices with a variety of tools and materials while building/creating prototypes
  • Reflect - students reflect on the results of their prototype testing and suggest areas of improvement

Co-constructing Learning

Students:
Saying, Doing, Representing

Educator:
Responding, Challenging

Identify and refine the problem to be solved/need to be met.

  • “What does the soil sifter have to do?”
  • “How do most sifters or separators work?”

Brainstorm and record criteria for the soil sifter.

  • “What words could we use to describe some of the features the soil sifter must have to be effective?”
  • “How many sizes of particles can we separate with the materials available?”

Make observations and decisions about the available tools and materials.

  • “What tools might you need for building the soil sifter?”
  • “What materials will work best for sifting?”
  • “How can the materials be combined into a system that sifts the soil into three sizes?”

Visualize and sketch a prototype.

  • “Why do engineers label all of the parts of their design sketches?”
  • “How are you going to represent each part of the soil sifter in the design sketch?”

Develop a design plan (e.g., identify the tasks or key steps involved in developing the solution, make decisions about tools and materials that will be needed, include labelled sketches)

  • “What are some of the materials that you think you will need?”
  • “How will you determine the sequence of steps you will need to follow to build a prototype soil sifter?”
  • “How will your labelled sketch help you to develop your plan?”

Construct and test a prototype of the soil sifter.

  • “Does the sifter work as planned? How do you know?”
  • “How can you be sure your soil sifter works consistently each time?”

Modify the prototype and retest it against the design criteria as necessary.

  • “What changes in your model might improve your results?”
  • “How would it change your design if you wanted the sifting process to go faster?”

Present and demonstrate their finished soil sifters to the class.

  • “What materials worked best? What materials did not work as well?”
  • “What challenges did your team encounter in working collaboratively to complete the challenge?”
  • “What would you do differently next time?”

Cross-Curricular Connections

Literacy

  • Communicating thoughts, feelings and ideas (e.g., contribute ideas to the design plan; brainstorm solutions for the soil sifter challenge)

Mathematical Thinking

  • measure mass and time using standard units (e.g., take measurements of the particle sizes in a soil mixture in preparation for designing the sifter; record time required to perform each sort of the soil mixture)
  • compare, describe and order objects using attributes measured in standard units (e.g., describe and order the screens and/or sieves for the soil sifter)
  • describe and interpret data (e.g., record time required to perform each sort of the soil mixture and evaluate and compare the efficiency of different designs or design modifications)

Piles of soil used for leveling terrain
(Photo by Alvesgaspar via Wikimedia Commons)

Extending the Learning

If your students are interested in learning more, the following may provoke their curiosity:

  • Challenge students to modify their soil sifter models to separate additional particle sizes.

  • Visit a local gravel pit, cement factory or landscaping supply business to see how stone is mined, processed and/or used as stone-based products.

  • If you have tomato seedlings available from your Tomatosphere™ Investigation, have students use the sifted soil components to do an inquiry comparing the growth of plants in the each of the components.



Stone products

Stone products featured in home design and landscaping
(Photo by Irina Stasiukova via Pexels)

Tomato plant

Tomato plant inquiry using different soils
(photo by Let’s Talk Science)