Lesson

Engage

• Encourage students to share the rusted items they brought in for the activity (see Teacher Notes: students should be encouraged in advance to bring in small, rusted items that are not pointed or sharp. Horseshoes, bolts, gate handles, and old tools work well.)
• Ask students to identify rusty items in their environment.
• Ask students to explain why they think rusting occurs and steps that can be taken to prevent rusting.
• Encourage students to give several examples of items that can rust and the means used to prevent them from rusting. It is likely that a student will mention cars. This discussion should lead to descriptions of environmental conditions that encourage rusting. Car dealers in the northern part of the country often obtain used cars from the south for parts for auto repair. Ask students why this makes sense.
  • cars are painted
  • steel pails are galvanized
  • playground equipment is painted or coated with a polymer
  • plates of magnesium or zinc are placed on ships and bridges blending metals that rust with other metals to form corrosion resistant alloys (stainless steel)
• Ask students if other metals oxidize or rust. Show examples of aluminum with a powdery aluminum oxide coating alongside heavily rusted iron objects. Ask students to describe the differences between the two objects and how the coating either supports or discourages further oxidation. [aluminum forms a powdered, smooth coating that prevents further oxidation, where iron forms rust flakes that allow for contact with more iron and further rusting] The teacher can also mention the Statue of Liberty is green because it’s made of copper, which has rusted over time. Copper rust is green, as opposed to iron rust that is red.

Explore

Students will use rusted items and/or steel wool to transfer a rust print to fabric or paper. They will use 50/50 vinegar/water solution but will be encouraged to explore the impact of adding salt to the mixture to maintain damp fabric or paper that is in contact with rusted items.

Have students…

1. Place the fabric or paper to be used on a plastic tray.
2. Dampen the fabric or paper by spraying it with the 50% vinegar solution.
3. Place rusty objects on the fabric or paper and cover with additional dampened fabric or paper. Items can also be rolled into the fabric or paper and weighted down with rocks or other heavy objects. If rolling method is used, students might consider using rubber bands to hold the rusted objects in close contact with fabric or paper.
4. Verify that the fabric or paper is damp and lightly cover with plastic, allowing for air to circulate.
5. Observe daily over several days, spraying as needed to keep materials damp.
6. After 5-7 days, rinse the fabric with tap water then wring out fabric or blot paper with dry paper towels. Allow to dry.
7. Clean up all materials as directed by the teacher.
8. If fabric is to be worn, it should be washed with a gentle detergent prior to wearing.

Explain

Students will use a collection of new, nonrusted as well as older rusty items including wire, bolts, tools, sprockets, pans, cooking items, irons, tractor or car parts, chain, hinges, and clean steel wool pads. Newer, nonrusted items can be placed in a shallow pan with water and vinegar to make them rusty and ready for the rust dying process.

Items will be placed on paper or fabric dampened by spraying with a 50/50 vinegar/water mixture. Students may experiment with adding table salt (NaCl) to the vinegar/water mix to explore the impact of salt upon rusting.

Place rusted metal items on the paper or fabric and place a second sheet of fabric or paper on top. To enhance the clarity of the prints on the fabric or paper, weight down the fabric using heavier items such as rocks.

A plastic sheet can be laid over the fabric or paper, but air needs to be able to access the fabric or paper.

Over the next few days, check the fabric or paper and mist as necessary to keep the fabric or paper damp.

Elaborate

Encourage student to explore additional rust dying techniques. Students might explore twisting and rolling fabric around rusty objects, folding items into fabrics or paper, and stuffing fabrics into rusty pots and kettles. The process could be tested with additional metals such as copper. Students could further explore optimizing conditions to promote rusting and explore the impact of changing the temperature for the rusting process.

Evaluate

Discussion Questions

Ask students…

1. Explain how they know that rusting is a chemical and not a physical change.
2. Why is it necessary to allow air to reach the fabric or paper as the paper or fabric is dyed?
3. What process always occurs alongside oxidation?
4. What happens to iron atoms when they rust? What do they become?
5. What sub-atomic particle is transferred in oxidation?
6. What might you change to enhance the rust design?
   1. Note that these questions can be further developed to create short answer and multiple choice items.
   2. always include one on experimental design
   3. if using model, ask about how model is similar and different to real life
   4. encourage students to back up claims with evidence and reasoning

Multiple Choice Items

1. What type of change is involved in rusting?
   a. Chemical change*
   b. Physical change
   c. Electrolysis
   d. Temperature change
2. Which always occurs with oxidation?
   a. Loss of mass
   b. Color change
   c. Reduction*
   d. Gain of electrons
3. Which of the following are used to prevent metals from rusting?
   a. Galvanizing
   b. Painting
   c. Coating with plastic
   d. All of the above*
4. Which subatomic particles are transferred in oxidation-reduction, or redox, reactions?
   a. Protons
   b. Neutrons
   c. Positrons
   d. Electrons*

Open-Ended Questions

1. Identify ways that items in your home are protected from oxidation or rusting?
   [Examples include: objects are painted, coated in plastic, stored in airtight containers, packaged with desiccants, galvanized]
2. What might you do to enhance the rust design obtained from this activity?
   [Use a different fabric or paper, use more/different rusted objects, try a different approach to create a design such as wrapping, rolling, or packing the dampened shirt or paper differently, add salt to the vinegar solution, alter the percentage of vinegar, try using different metals, try waiting longer, vary the temperature]

Cross-Disciplinary Extensions

Connect to Math

Students explore the quantity of electrons transferred in the formation of metal oxides.

Connect to Reading

Use web resources, such the following regarding the preservation of iron ships and rust prevention.

• Preservation of Iron Ships in the Marine Environment
• Rusting and Rust Prevention

Explain the impact of corrosion on the shipping industry and means used to protect ships.

Connect to Writing

Study the impact of rusting and corrosion on the environment. Write a news article explaining why the prevention of corrosion is essential to protecting the environment.

Connect to Social Studies

Oil and natural gas pipelines have been very controversial means of delivering fossil fuels from remote to more populated areas. Investigate the reasons behind the political controversy and write a brief opinion essay explaining the reasons behind the controversy, including your opinions on the issue.

Next Generation Science Standards

This lesson supports the following:

Practices of Science and Engineering

• Asking questions and defining problems
• Planning and carrying out investigations
• Constructing explanations and designing solutions

Cross-Cutting Concepts

• Patterns
• Cause and Effect: Mechanism and Explanation
• Energy and Matter: Flows, Cycles, and Conservation
• Structure and Function
• Stability and Change

Disciplinary Core Ideas, Grades 6-8

Physical science

• Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms. (MS-PS1-1)
• Solids may be formed from molecules, or they may be extended structures with repeating subunits (e.g., crystals). (MS-PS1-1)
• Each pure substance has characteristic physical and chemical properties (for any bulk quantity under given conditions) that can be used to identify it. (MS-PS1-2),(MS-PS1-3)
• Gases and liquids are made of molecules or inert atoms that are moving about relative to each other. (MS-PS1-4)
• In a liquid, the molecules are constantly in contact with others; in a gas, they are widely spaced except when they happen to collide. In a solid, atoms are closely spaced and may vibrate in position but do not change relative locations. (MS-PS1-4)
• Substances react chemically in characteristic ways. In a chemical process, the atoms that make up the original substances are regrouped into different molecules, and these new substances have different properties from those of the reactants. (MS-PS1-2),(MS-PS1-3),(MS-PS1-5)
• Substances react chemically in characteristic ways. In a chemical process, the atoms that make up the original substances are regrouped into different molecules, and these new substances have different properties from those of the reactants. The total number of each type of atom is conserved, and thus the mass does not change. Some chemical reactions release energy, others store energy. (MS-PS1-2)

Engineering Design

• A solution needs to be tested, and then modified on the basis of the test results, in order to improve it. (MS-ETS1-4)
• Although one design may not perform the best across all tests, identifying the characteristics of the design that performed the best in each test can provide useful information for the redesign process—that is, some of those characteristics may be incorporated into the new design. (MS-ETS1-3)
• The iterative process of testing the most promising solutions and modifying what is proposed on the basis of the test results leads to greater refinement and ultimately to an optimal solution. (MS-ETS1-4)