Large Plastic Tub Or Other Container for Sand

Lesson Title: Sifting Sand /
Grade Level: 8 / Quarter: 1st
Standards: List relevant STEM – Science, Technology, & Math standards. Include ELA CCGPS if applicable.
Science Georgia Standards of Excellence
S8P1. Obtain, evaluate, and communicate information about the structure and properties of matter.

Develop and use a model to compare and contrast pure substances (elements and compounds) and mixtures.

Construct an argument based on observational evidence to support the claim that when a change in a substance occurs, it can be classified as either chemical or physical.

Math Georgia Standards of Excellence
MGSE6.RP.3c Find a percent of a quantity as a rate per 100 (e.g. 30% of a quantity means 30/100
times the quantity)
Science and Engineering Practices / Crosscutting Concepts
Asking Questions and Defining ProblemsA practice of science is to ask and refine questions that lead to descriptions and explanations of how the natural and designed world works and which can be empirically tested.
Developing and Using Models A practice of both science and engineering is to use and construct models as helpful tools for representing ideas and explanations.
Constructing Explanations and Designing Solutions The products of science are explanations and the products of engineering are solutions. / Structure and function. The way in which an object or living thing is shaped and its substructure determine many of its properties and functions.
Systems and system models. Defining the system under study—specifying its boundaries and making explicit a model of that system—provides tools for understanding and testing ideas that are applicable throughout science and engineering.
Lesson Essential Question:
How can physical and chemical properties of matter determine how substances mix, combine, and separate? / Vocabulary:
element: A substance consisting of only one type of atom
compound: A pure chemical substance consisting of two or more different elements that are chemically combined
mixture: A substance consisting mixing two or more materials that are not chemically combined
heterogeneous mixture: A mixture that consists of visibly different substances or phases.
homogeneous mixture: A mixture that has the same uniform appearance and composition throughout its mass.
solution:another name for a homogeneous mixture
Lesson Materials

Large plastic tub or other container for sand
20-pound bag of play sand (green sand can be used to represent toxic sand)
Electronic scale
Nuts, bolts, and washers:
8 washers
8 bolts
8 nuts
1 nut with 1 bolt (4 sets)
2 nuts with 1 bolt (4 sets)
1 nut and 1 washer with 1 bolt (4 sets)
2 washers, 2 nuts, 1 bolt
Anyof the materials listed below in Step #3. These items can be provided by the teacher or students can bring them from home. The teacher may also make changes to the list.

/ Lesson Assessment:

Sifting Sand Student Worksheet
Sifting Sand Rubric

STEM Challenge Overview: Students work in teams to design a device that will separate a mixture of sand, nuts, bolts, washers, and various combinations of nuts, bolts, and washers. Each group is given two minutes to retrieve as many of the objects as possible. A mathematical analysis discloses the effectiveness of the student models. Students relate the nuts, bolts, washers, and combinations to elements, compounds, and mixtures.
Teacher Background:
Students should know the characteristics of elements, compounds, and mixtures (both heterogeneous and homogeneous) before beginning this lesson. To illustrate the differences and to reinforce understanding, prepare a table with the following: a small piece of copper pipe or wire, a spoonful of table salt, a small amount of trail mix, and a glass of Kool-Aid or water with a drop or two of food coloring. Have students discuss characteristics of the substances and label each as element, compound, heterogeneous mixture, or homogeneous mixture (solution).
On a second table display an arrangement of nuts, bolts, washers, and various combinations of the three. Have students relate the single nuts, bolts, and washers to elements and the combinations to compounds. Each single piece is like one atom. Nuts are all one type of atom, representing an element. Bolts and washers represent different elements. When the atoms of various elements are chemically combined, they form compounds. Chemical combinations are modeled by joining the pieces together. Have volunteers physically group the various pieces to model heterogeneous and homogeneous mixtures.
Students are challenged to design a method of separating the nuts, bolts, washers, and combinations from a mixture of “toxic” sand while standing on a “bridge” over the sand. The teacher will need to prepare the following:

A plastic container with enough sand to dig.
Nuts, bolts, washers and combinations as described in the materials list, buried in the sand.
A simulated bridge. This could be the top of a science table or a ladder. Safety precautions must be observed.

Proper supervision is imperative, especially if students punch holes in materials to create a sieve. An electronic scale should be set up to measure the amount of any sand retrieved along with elements and compounds.
INSTRUCTION

Ask/Engage

You and your friends have been employed to extract valuable elements and compounds from an area of toxic sand below a small bridge. There is no land access to the sand below, so your team must design and build a method of separating the elements and compounds from the sand while standing on the bridge.

Imagine/Brainstorm

Think about how you might be able to remove the items from the sand. Some things you need to know and understand:

You must stand on the bridge as you retrieve the material.
You will have two minutes to retrieve the items.
No one can touch the sand.
No sand should be included in retrieved material.
Only approved materials may be used to build.

On the student worksheet, draw and label one or two designs for a device that would accomplish the task.

Plan/Design

Present your best ideas(s) for solving the problem to your group and listen to the ideas of other team members. Collaboratively with your team, design a final product and process to retrieve and sort the objects. Draw and label the final design plan then make a list of supplies you will need on the student worksheet. You may use any of the items on the approved supply list below. Some items on the list are not provided, but may be brought from home. If you want to use items not on the pre-approved list, you MUST get approval from your teacher before proceeding further.

Create / Test

With your team, build your device according to the design plan. Test the device by standing at the position designated by your teacher. Collect data on the percentage of materials recovered in the time allowed (two minutes). Determine the effectiveness of your machine. Record your data on the student worksheet.

Evaluate/Improve – and repeat Steps 1-5

Use the Sifting Sand rubric to evaluate the success of your design. With your group, answer the questions on the student worksheet. Brainstorm improvements that would make the product more effective. Draw and label the new/revised plan. If time permits, test your improvements and record your results on the student worksheet.

Sifting Sand Rubric

25 Points / 22 Points / 19 Points / 16 Points
Product retrieval effectiveness / Picked up 90 to 100 percent of the objects / Picked up 80 to 89 percent of the objects / Picked up 70 to 79 percent of the objects / Picked up less than 70 percent of the objects
Mixture separation effectiveness / Less than 5 grams ofsand retrieved with objects / 5 – 20 grams of accumulated sand or one or more objects have sand stuck to them / 21 to 50 grams of accumulated sand / More than 50 grams of accumulated sand
Widespread Effectiveness / Device collected samples of all possible types / Device collected samples of five or six of the seven possibe types / Device collected samples of three or four of the seven possible types / Device collected samples of less than three of the possibe types
Communication of results / All information complete, thorough and accurate / All questions answered accurately, but some missing detail / All questions answered, but there are some inaccuracies / ZERO points if questions are left unanswered on the final report

Sifting Sand Student Worksheet

Challenge Overview:You and your friends have been employed to extract valuable elements and compounds from an area of toxic sand below a small bridge. There is no land access to the sand below, so your team must design and build a method of separating the elements and compounds from the sand while standing on the bridge. Since the items have been buried in toxic sand, you may not touch them or the sand.

ASK / ENGAGE: What is the problem you are being asked to solve?

______

IMAGINE/BRAINSTORM: Think about how you might be able to remove the items from the sand and stay within the constraints described above.

On your own, draw and label one or two designs below:

Sifting Sand Lesson Plan

PLAN/DESIGN: Present your best ideas(s) to your group and listen to the ideas of other team members. Collaboratively with your team, design a final product and process to retrieve and sort the objects. Draw and label the final design plan then make a list of supplies you will need. You may use any of the items on the approved supply list below. Some items on the list are not provided, but may be brought from home. If you want to use items not on the pre-approved list, you MUST get approval from your teacher before proceeding further.

Team Design Plan / Materials List

CREATE/TEST:With your team, build your device according to the design plan. Test the device by standing at the position designated by your teacher. When the timer begins, retrieve and sort as many of the items as possible in two minutes. Record the number of each type of item you successfully recover in the chart below.

Item / Nut Only / Bolt Only / Washer Only / 1 Nut and 1 Bolt / 2 nuts and 1 bolt / 1 nut, 1 washer and 1 bolt / 2 washers, 2 nuts, 1 bolt / TOTAL
Number Retrieved
Number Possible / 8 / 8 / 8 / 4 / 4 / 4 / 4 / 40
Percentage Retrieved **

**To find percentage retrieved, divide number retrieved by the number possible, then multiply by 100.

What percentage of the total material did you retrieve? ______

EVAULATE/IMPROVE: Use the Sifting Sand rubric to evaluate the success of your design. How well did your design work (what is your total score for the first three lines of the rubric)?______

Did your solution solve the problem within the given constraints? ______

If your solution did not completely solve the problem within the given constraints, what did not go right?

Brainstorm improvements that would make the product more effective. Draw and label the new/revised plan.

Re-Test

**To find percentage retrieved, divide number retrieved by the number possible, then multiply by 100.

What percentage of the total material did you retrieve? ______

Use the Sifting Sand rubric to evaluate the success of your design. How well did your re-design work (what is your total score for the first three lines of the rubric)?______

Did your revised plan give you better results? ______

What ideas do you have for further improvements?

Understanding the Science

How are the nuts, bolts, and washers like elements?

How are the connected pieces like compounds?

Describe the properties of matter you used to separate the mixture.

How are the hardware connections like chemical bonds?

Why is it more difficult to separate compounds into separate elements than it is to separate the components of mixtures?

Using the nuts, bolts, and washers analogy, draw representations of the following:

If you were given an unlimited number of nuts, bolts, and washers, how many different combinations could you create? Explain.

What percentage of matter on Earth is composed of combinations of individual elements? ______

Sifting Sand Lesson Plan