Nano Waterproofing
This lesson explores how materials can be modified at the nano scale to provide features such as waterproofing and stain resistance. Student teams develop their own waterproofing technique for a cotton fabric and test their design against a fabric that has been altered through nanotechnology applications.
- Learn about nanotechnology.
- Learn about the hydrophobic effect.
- Learn about surface area.
- Learn about teamwork and working in groups.
Age Levels: 8-18
Build Materials (For each team)
Required Materials
- Four 4″ x 4″ pieces of plain white cotton fabric
- One 4″ x 4″ piece of waterproof fabric (that has been adjusted at the nano level – not treated with waterproof spray). Fabric can be found on amazon.com or a local craft goods store.
- Wax
- Crayons
- Flax seed
- Coconut oil/Crisco
- Lanolin
- Clay
- Glue
- Soons or craft sticks for smoothing
Testing Materials
- Water (or colored water/juice)
- Sink or bucket
Materials
- Water (or colored water/juice)
- Sink or bucket
- Microscope or camera scope (optional)
Process
Over a bucket or sink, pour water over each piece of fabric as teams observe whether the water beads up or is absorbed. If possible, you can use colored water or juice to better see if the liquid is absorbed.
Design Challenge
You are part of a team of engineers who have been given the challenge to develop a new process for waterproofing clothing. For the purposes of your challenge, “waterproof” means that water should not be absorbed by the fabric, but will bead up on the fabric instead.
Criteria
- Water must bead up on the fabric.
Constraints
- Use only the materials provided.
- Break class into teams of 2-3.
- Hand out the Nano Waterproofing worksheet, as well as some sheets of paper for sketching designs.
- Discuss the topics in the Background Concepts Section. Consider asking students what items of clothing that you have which are waterproof. What makes them waterproof?
- Review the Engineering Design Process, Design Challenge, Criteria, Constraints and Materials.
- Provide each team with their materials.
- Explain that students must devise a way to “waterproof” a piece of fabric that ultimately would be made into a shirt. In this case, “waterproof” means that water should not be absorbed by the fabric, but will bead up on the fabric instead.
- Announce the amount of time they have to develop and apply their waterproofing approaches (1 hour recommended).
- Use a timer or an on-line stopwatch (count down feature) to ensure you keep on time. (www.online-stopwatch.com/full-screen-stopwatch). Give students regular “time checks” so they stay on task. If they are struggling, ask questions that will lead them to a solution quicker.
- Students meet and develop a written plan for three different approaches: Fabric A, Fabric B, and Fabric C (a fourth fabric piece is provided in case of errors). They agree on the materials they will need.
- Students apply their approach to 3 pieces of fabric. They should mark each piece of fabric so that they know which process was applied.
- Instruct students to visually examine each piece of fabric (access to a microscope is helpful). They should document what they see, noting both what they see and how the fabric samples differ from each other. They should note whether the fabric surfaces appear smooth, bumpy, convex, concave, or have other characteristics. Students should then inspect the sample nano fabric and note their observations.
- Next, instruct students to test their waterproofing approaches. Over bucket or sink, pour water over each piece of fabric as teams observe whether the water beads up or is absorbed. If possible, you can use colored water or juice to better see if the liquid is absorbed.
- Teams should document how waterproof each piece of fabric was.
- As a class, discuss the student reflection questions.
- For more content on the topic, see the “Digging Deeper” section.
Extension Idea
Have older students attempt to remove the waterproofing feature of nano fabrics in any way they can think of. For example, they might scrub the surface, dye it, boil it, wash it, freeze it, or iron it.
Optional Modelmaking Extension
Have students build a model representing the Hydrophobic effect. This could be done with a foam ball with straws or toothpicks attached to simulate the tiny hairlike projections that keep water off the direct surface of some leaves. This will also help visually illustrate how waterproofing works at the nano scale.
Student Reflection (engineering notebook)
- Did any of your fabrics prove to be waterproof? If yes, which procedure do you think was the best, and why? If no, why do you think your procedures did not work?
- What solution of another team do you think worked best? Why?
- What do you think would happen if you washed and dried your fabric? Would it retain the waterproofing?
- What was the most surprising observation during the microscope comparison (if you completed that part of the activity)?
- How did the nano treated fabric compare to your most successful fabric in the water test?
- How did the nano treated fabric compare to your most successful fabric under the microscope?
- If you had to do it all over again, how would your team have approached this challenge differently? Why?
- Do you think that materials engineers have to adapt their original ideas during product testing? Why might they?
- Did you find that there were many different solutions in your classroom that met the project goal? What does this tell you about how engineering teams solve problems in the real world?
- Do you think you would have been able to complete this project easier if you were working alone? Explain…
- What other applications can you think of where a surface might be changed at the nano scale to improve function or performance? One idea is coating windshields so water flows off faster…..what can you think of?
Time Modification
The lesson can be done in as little as 1 class period for older students. However, to help students from feeling rushed and to ensure student success (especially for younger students), split the lesson into two periods giving students more time to brainstorm, test ideas and finalize their design. Conduct the testing and debrief in the next class period.
What is Nanotechnology?
Imagine being able to observe the motion of a red blood cell as it moves through your vein. What would it be like to observe the sodium and chlorine atoms as they get close enough to actually transfer electrons and form a salt crystal or observe the vibration of molecules as the temperature rises in a pan of water? Because of tools or ‘scopes’ that have been developed and improved over the last few decades we can observe situations like many of the examples at the start of this paragraph. This ability to observe, measure and even manipulate materials at the molecular or atomic scale is called nanotechnology or nanoscience. If we have a nano “something” we have one billionth of that something. Scientists and engineers apply the nano prefix to many “somethings,” including meters (length), seconds (time), liters (volume) and grams (mass) to represent what is understandably a very small quantity. Most often nano is applied to the length scale and we measure and talk about nanometers (nm). Individual atoms are smaller than 1 nm in diameter, with it taking about 10 hydrogen atoms in a row to create a line 1 nm in length. Other atoms are larger than hydrogen but still have diameters less than a nanometer. A typical virus is about 100 nm in diameter and a bacterium is about 1000 nm head to tail. The tools that have allowed us to observe the previously invisible world of the nanoscale are the Atomic Force Microscope and the Scanning Electron Microscope.
How Big is Small?
It can be hard to visualize how small things are at the nanoscale. The following exercise can help you visualize how “big” small can be! Consider a bowling ball, a billiard ball, a tennis ball, a golf ball, a marble, and a pea. Think about the relative size of these items.
Scanning Electron Microscope
The scanning electron microscope is a special type of electron microscope that creates images of a sample surface by scanning it with a high energy beam of electrons in a raster scan pattern. In a raster scan, an image is cut up into a sequence of (usually horizontal) strips known as “scan lines.” The electrons interact with the atoms that make up the sample and produce signals that provide data about the surface’s shape, composition, and even whether it can conduct electricity. Many images taken with scanning electron microscopes maybe viewed at www.dartmouth.edu/~emlab/gallery
- Constraints: Limitations with material, time, size of team, etc.
- Criteria: Conditions that the design must satisfy like its overall size, etc.
- Engineers: Inventors and problem-solvers of the world. Twenty-five major specialties are recognized in engineering (see infographic).
- Engineering Design Process: Process engineers use to solve problems.
- Engineering Habits of Mind (EHM): Six unique ways that engineers think.
- Hydrophobic: A property of molecules that do not mix with water.
- Iteration: Test & redesign is one iteration. Repeat (multiple iterations).
- Nanotechnology: Ability to observe, measure and even manipulate materials at the molecular or atomic scale.
- Prototype: A working model of the solution to be tested.
- Scanning Electron Microscope: Special type of electron microscope that creates images of a sample surface by scanning it with a high energy beam of electrons in a raster scan pattern.
- Waterproofing: Making something resistant to water.
Recommended Reading
- Nanotechnology For Dummies (ISBN: 978-0470891919)
- Nanotechnology: Understanding Small Systems (ISBN: 978-1138072688)
Writing Activity
Write an essay or a paragraph about potential benefits of applying nanotechnology to fabrics, surfaces, or materials used in hospitals or nursing homes?
Alignment to Curriculum Frameworks
Note: All lesson plans in this series are aligned to the National Science Education Standards which were produced by the National Research Council and endorsed by the National Science Teachers Association, and if applicable, also to the International Technology Education Association’s Standards for Technological Literacy or the National Council of Teachers of Mathematics’ Principles and Standards for School Mathematics.
National Science Education Standards Grades K-4 (ages 4 – 9)
CONTENT STANDARD A: Science as Inquiry
As a result of activities, all students should develop
- Abilities necessary to do scientific inquiry
- Understanding about scientific inquiry
CONTENT STANDARD B: Physical Science
As a result of the activities, all students should develop an understanding of
- Properties of objects and materials
CONTENT STANDARD E: Science and Technology
As a result of activities, all students should develop
- Abilities of technological design
- Abilities to distinguish between natural objects and objects made by humans
CONTENT STANDARD F: Science in Personal and Social Perspectives
As a result of activities, all students should develop understanding of
- Science and technology in local challenges
National Science Education Standards Grades 5-8 (ages 10 – 14)
CONTENT STANDARD A: Science as Inquiry
As a result of activities, all students should develop
- Abilities necessary to do scientific inquiry
- Understandings about scientific inquiry
CONTENT STANDARD B: Physical Science
As a result of their activities, all students should develop an understanding of
- Properties and changes of properties in matter
CONTENT STANDARD E: Science and Technology
As a result of activities in grades 5-8, all students should develop
- Abilities of technological design
- Understandings about science and technology
CONTENT STANDARD F: Science in Personal and Social Perspectives
As a result of activities, all students should develop understanding of
- Science and technology in society
National Science Education Standards Grades 9-12 (ages 14 – 18)
CONTENT STANDARD A: Science as Inquiry
As a result of activities, all students should develop
- Abilities necessary to do scientific inquiry
- Understandings about scientific inquiry
CONTENT STANDARD B: Physical Science
As a result of their activities, all students should develop understanding of
- Structure of atoms
- Structure and properties of matter
CONTENT STANDARD E: Science and Technology
As a result of activities, all students should develop
- Abilities of technological design
- Understandings about science and technology
CONTENT STANDARD F: Science in Personal and Social Perspectives
As a result of activities, all students should develop understanding of
- Science and technology in local, national, and global challenges
Standards for Technological Literacy – All Ages
The Nature of Technology
- Standard 1: Students will develop an understanding of the characteristics and scope of technology.
- Standard 3: Students will develop an understanding of the relationships among technologies and the connections between technology and other fields of study.
Design
- Standard 9: Students will develop an understanding of engineering design.
- Standard 10: Students will develop an understanding of the role of troubleshooting, research and development, invention and innovation, and experimentation in problem solving.
Abilities for a Technological World
- Standard 11: Students will develop abilities to apply the design process.
- Standard 13: Students will develop abilities to assess the impact of products and systems.
The Designed World
- Standard 19: Students will develop an understanding of and be able to select and use manufacturing technologies.
Industrial Engineering
Computer Engineering
You are part of a team of engineers who have been given the challenge to develop a new process for waterproofing clothing. You have been provided with several pieces of cotton along with many possible materials you might decide to use for your waterproofing technique. For the purposes of your challenge, “waterproof” means that water should not be absorbed by the fabric, but will bead up on the fabric instead. You may try two or three different solutions and see which works best!
Planning Stage
Meet as a team and discuss the problem you need to solve. Use the box below to describe your solution and list the materials you think you’ll need to meet the challenge. Explain why you think your solution will solve the problem!
|
Fabric A Your plan and hypothesis:
Materials Needed:
|
|
Fabric B Your plan and hypothesis:
Materials Needed:
|
|
Fabric C Your plan and hypothesis:
Materials Needed:
|
Manufacturing Stage
Execute each of your plans (be sure to mark each piece of fabric, so you know what process you applied to it).
Investigation Stage
If you have access to a microscope, examine each of your pieces of fabric and in the box below describe what you see, noting both what you see and how they differ from the other fabric samples. You’ll have a chance to examine a sample of fabric that has been altered at the nano level too! Consider whether the fabric surfaces appear smooth, bumpy, convex, concave, or have other characteristics.
| Surface Observations | |||
| Fabric A | Fabric B | Fabric C | Nano Fabric |
|
|
|||
Testing Stage
Over a wash basin or sink pour water over your fabric and see if it beads up or is absorbed. If your teacher agrees, you may wish to use a colored water or juice to more easily see if the water is absorbed at all. Mark your observations below.
| Water Test Observations | |||
| Fabric A | Fabric B | Fabric C | Nano Fabric |
|
|
|||
Evaluation Phase
Complete the following questions as a group:
- Did any of your fabrics prove to be waterproof?
If yes, which procedure do you think was the best, and why?
If no, why do you think your procedures did not work?
- What solution of another team do you think worked best? Why?
- What do you think would happen if you washed and dried your fabric? Would it retain the waterproofing?
- What was the most surprising observation during the microscope comparison (if you completed that part of the activitiy)?
- How did the nano treated fabric compare to your most successful fabric in the water test?
- How did the nano treated fabric compare to your most successful fabric under the microscope?
- If you had to do it all over again, how would your team have approached this challenge differently? Why?
- Do you think that materials engineers have to adapt their original ideas during product testing? Why might they?
- Did you find that there were many different solutions in your classroom that met the project goal? What does this tell you about how engineering teams solve problems in the real world?
- Do you think you would have been able to complete this project easier if you were working alone? Explain…
11. What other applications can you think of where a surface might be changed at the nano scale to improve function or performance? One idea is coating windshields so water flows off faster…..what can you think of?
Downloadable Student Certificate of Completion
