Introduction To Nanotechnology

Module 1: What is Nanotechnology?1 The primary purpose of this teaching module is to explain key concepts of nanotechnology and its basic theoretical underpinnings. Many students will see the tremendous applications of such technologies within their lifetimes, and various nanotechnologies are already on the market today. Because of its impact, students should have a rudimentary understanding of nanotechnology and how it affects their lives. In order to provide a teaching module that will contain these qualities, multiple lesson plans have been created to divide the subject into understandable topics for the students. First, teachers will define nanotechnology as being comprised of “nanostructures” or “nanomaterials” that possess at least one dimension that measures approximately less than 100nm AND exhibit novel properties. Because one nanometer is one-billionth of a meter, students may initially have difficulty conceiving of such a small scale. Activities are included to help them visualize the smallness and uniqueness of nanostructures. Once the concept of nanoscale size is understood, the students will be made aware of some of the current and future applications of nanotechnology. Furthermore, students will develop a level of appreciation of how such technology might influence society in both positive and negative ways. Students will also be curious about the methods employed for manufacturing nanostructures. Therefore, two general approaches used to synthesize nanostructured materials will be discussed: “bottom-up” and “top-down” fabrication. “Bottom-up” refers to the assembly of a nanostructure by beginning with individual atoms/molecules and building up through the addition of more atoms/molecules until the structure is completely formed. This method can be related to the construction of a model airplane or using Legos to construct a tower. “Top-down” assembly is similar to carving wood into a desired shape. This method begins with a large sample of a material that is stripped away until the microstructures or nanostructures are formed. In order for students to obtain a full appreciation for both methods of production, they will complete an activity to better understand these concepts. A bonus activity is provided that explores futuristic concepts about nanomachines or nanobots that build bottom-up technologies. Assessment of students’ comprehension may be achieved through the various activities and assignments included in the teaching module to help the teacher evaluate the students’ ability to think critically and apply the concepts that they have learned in this introductory unit. Some suggested affordable texts that the teacher might consider referencing include: Booker and Boysen, Nanotechnology for Dummies, For Dummies, 2005 or Jones, Soft Machines: Nanotechnology and Life, Oxford University Press, 2008. There are also numerous web sites that discuss various aspects of nanotechnology. For the purpose of this teaching module, the teacher might consider referencing the following: http://en.wikipedia.org/wiki/Nanotechnology http://www.nanotechproject.org http://nanopedia.case.edu (use the search function to find descriptions about specific topics) 1

This module was prepared by faculty and students at Case Western Reserve University with help from middle and high school teachers at Hathaway Brown School and Shaker Heights High School, both located in Shaker Heights, Ohio. This material is provided for educational purposes and may be duplicated and distributed for non-commercial use only. The work done for this teaching module development was supported by a grant from the National Science Foundation under grant# 0407208. Please send feedback regarding this module to: [email protected].

Lesson Plan I: What is Nanotechnology? SUBJECT: Introduction to nanotechnology GRADE LEVEL: 7-12 LENGTH: 1-3 class periods depending number of activities attempted/accomplished in class OVERVIEW: A brief introduction of nanotechnology in which aspects of nanotechnology are described and discussed. In order for a structure or device to be classified as nanotechnology, the scale must be less than approximately 100nm in one dimension. Additionally, the structure must have novel properties due its small size. Students should be able to understand the size of a nanometer, which is one billionth of a meter. OBJECTIVES: By the end of this lesson, students will be able to: • Explain the requirements of nanotechnology (structures less than ~100nm with novel properties) • Provide analogies to illustrate the size of a nanometer. ANTICIPATORY SET: Focus Student Attention: Show one or both of the following video clips available at: http://mrsec.wisc.edu/Edetc/cineplex/live5.html http://www.youtube.com/watch?v=S4CjZ-OkGDs Motivate students: Nanotechnology can change the world. Nanotechnology can improve health care, provide better energy sources, advance water purification techniques and lead to the manufacture of new materials that will improve a wide variety of applications that influence our lives. Today we will discuss how nanotechnology is defined. ACTIVITIES (you may choose to do these activities spread over 1-3 periods): • Ask students to write a short in-class essay on what they know about nanotechnology. Encourage them to think about where they have heard the term “nano” before. They may share their essay with the class or hand it in as an assignment. • Using the slide presentation, “What is Nanotechnology,” included with this module, the teacher may give a short lecture about how nanotechnology is categorized by size and properties, and relay how properties and functions change at this scale. The presentation summarizes that nanotechnologies are typically comprised of structures with at least one dimension that falls between 1 and 100 nanometers. Materials assume unique characteristics at this size, including changes in mechanical (e.g. strength), electrical (e.g. conductivity), chemical (e.g. reactivity), magnetic, thermal and optical (e.g. transparency) properties. The presentation contains slides for the teacher to use/follow during the lecture. Due to copyright issues, we are only able to provide slides with images in pdf format. Nonetheless, we also provide the text only slides in PowerPoint format. The teacher may consider putting together his/her own slides using this presentation as a guide. • Divide the class into groups of 3 or 4 students. Give each group time to devise two different analogies or pictorial representations of size: one should describe how big one billion is, and the other should illustrate how small one nanometer is. For example: one

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billion M&M’s lined up side-by-side would stretch from Boston, MA to San Francisco, CA and back again. A sheet of printer paper is 8.5” wide and 11” long, which is equivalent to 215,900,000 by 279,400,000 nm. You may choose to allow the use of computers so the students can research sizes and distances to which they can more easily relate. After this research period, have each group explain their analogies to the rest of the class. Have students build their own buckyball, a type of nanoparticle, the most common of which contains exactly sixty carbon atoms arranged in a structure that resembles a soccer ball. The diameter of this kind of buckyball is about 1 nm, so obviously the students will be building a very large scale model. Instructions are provide here: http://nanopedia.case.edu/NWPage.php?page=nw.nanotubes.mod.6. A template of the 20 hexagons and 12 pentagons that each student will need in order to cut out the shapes is included with this teaching module and is titled, “20 Hexagons and 12 Pentagons.” (Use this rather than making your own as suggested on the Nanopedia web site.) Each student will also need scissors and tape. Ask the students to determine how many times bigger the model is as compared to the actual size of a buckyball.

CLOSURE: With any remaining time, ask students to list as many fields/applications as they can think of in which they think nanotechnology may help improve an existing application or create a new one. (The teacher may want to consult the included presentations, “Current Applications of Nanotechnology” or “Future Applications of Nanotechnology” to make initial suggestions in case the students are having trouble coming up with their own ideas.) Make a list of these on the board (do not discuss or criticize suggestions – this is a brainstorming session), and tell them that in the next lesson, they will be learning more about how nanotechnology can be applied. Keep this list to use at the beginning of Lesson II.

Lesson Plan II: Applications of Nanotechnology SUBJECT: Introduction to nanotechnology GRADE LEVEL: 7-12 LENGTH: 1-3 class periods depending number of activities attempted/accomplished in class OVERVIEW: By familiarizing themselves with current and potential applications of nanotechnology, the students can gain more working knowledge and appreciation of the subject. The applications illustrate how nano-properties affect the products created. OBJECTIVES: By the end of this lesson, students will be able to: • Describe many current applications of nanotechnology •

Describe some potential applications of nanotechnology in the future

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Name and explain some pros and cons of applications of nanotechnology

ANTICIPATORY SET: Focus student attention: Hang an item of stain resistant clothing and a non-treated piece of fabric from the board. (While there are many suppliers of nano-enhanced stain resistant clothing, they do not necessarily market their products as such. Nonetheless, we suggest going to www.amazon.com and searching for “nano-tex” or “nanotex” – you should be able to find a clothing item for less than $30.) Provide the students with small water guns filled with redcolored juice, and allow students to take aim at the pieces of clothing. Have the students observe and qualitatively analyze the effects – discuss in class. You can explain that the fibers are encapsulated by whisker-like nanofibers that prevent liquid molecules from penetrating and staining the fabric. Liquid “rolls” off the fibers rather than soaking in. The company, Nano-Tex, manufactures stain-resistant clothing enabled by nanotechnology. Their “brand partners” are listed here: http://www.nano-tex.com/company/brand_partners.html. Motivate students: Today, we will find out about some of the current and future applications of nanotechnology. We will discuss how these applications are affecting commercial products around the world. ACTIVITIES: •

Discuss the list the students created at the end of Lesson I, describing applications in which nanotechnology can impact technological development. Discuss their answers – are the suggestions potentially real or more futuristic? Then introduce some of the current applications in nanotechnology using the presentation slideshow included with this teaching module, “Current Applications of Nanotechnology,” emphasizing how nanotechnology has improved the product (specific information is given on the slides). This presentation contains slides for the teacher to use/follow during the lecture. Due to copyright issues, we are only able to provide slides with images in pdf format. Nonetheless, we also provide the text only slides in PowerPoint format. The teacher may consider putting together his/her own slides using this presentation as a guide. For a more comprehensive listing of nanotechnology products, go to: http://www.nanotechproject.org/inventories/consumer/browse/categories/.

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There are many, many ongoing research projects that explore more futuristic applications of nanotechnology. Point out the more futuristic applications that appear on the list the students developed. Next, introduce some more futuristic applications of nanotechnology described in the presentation, “Future Applications of Nanotechnology” (again, specific information is provided on the slides).

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Bonus activity: have the students choose one current or future application that was presented and research it further on the internet. They should write a summary essay (approximately 300 words) describing this application further.

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Have students gather in groups to brainstorm some potential pros and cons of the nanotechnology applications. For example, some risks may be: unknown effects of nanostructures on the environment or human health; unfair advantage in sports for athletes using nano-enhanced equipment; or stronger composite frames in some cars may mean more damage to cars without nano-enhanced frames after an accident. For this teaching module, emphasis is on the benefits of nanotechnology applications. For more information on the potential risks of nanotechnology, teachers (and/or students) may choose to visit: http://www.nsec.wisc.edu/NanoRisks/NS--NanoRisks.php.

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Homework #1 may be given to students after this lesson.

CLOSURE: Summarize the current and future applications of nanotechnology and the positive and negative aspects of the field that were discussed in class. The teacher should emphasize that throughout time, humans have developed new technologies that have benefited society in many ways, and in some cases, technological development has led to some negative consequences. More so than ever before, scientists around the world are researching the potential negative effects of this new technology so that potential problems may be resolved proactively rather than reactively.

Lesson III: Bottom Up and Top Down Production SUBJECT: Introduction to nanotechnology GRADE LEVEL: 7-12 LENGTH: 1-2 class periods OVERVIEW: The concepts of “bottom-up” and “top-down” production are important when learning about nanotechnology. Bottom-up refers to the assembly of a structure atom by atom. This method is analogous to the assembly of a model airplane piece by piece. In Lesson I, the students used a bottom-up method to build a buckyball. Top-down production is similar to carving wood into a desired shape. Therefore, the top-down method begins with a large piece of material that is stripped away until a nanostructure is formed. OBJECTIVES: By the end of this lesson, students will be able to: • Define “bottom-up” versus “top-down” fabrication •

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Describe the pros and cons of each approach: o Bottom-up synthesis enables extreme control of size and chemical composition, but interactions limit the ability to manipulate the exact position of the atoms o Top-down fabrication is often more easily accomplished using proven techniques, but a lot of material is wasted Bonus material: Understand and explain the “fat, sticky fingers” phenomenon as it relates to nanobots or nanomachines. This phenomenon is an argument that debunks the notion of creating mechanical molecular assemblers in the future. In essence, the theory suggests that nanomachines or nanobots, made of atoms themselves, will never be able to manipulate other atoms with atomic precision because too many nanomachines would be required to do the job in a very small space. Additionally, atoms always interact in some way with nearby atoms, and consequently, the nanomachines will have difficulty picking up and releasing atoms in specific locations at will. More detail about the theory can be found here: http://www.hyle.org/journal/issues/10-2/bueno.htm.

ANTICIPATORY SET: Review previous lesson: Ask students to recall applications of nanotechnology. Focus student attention: Have a video clip running that shows self-assembly. Good examples are: http://www.sigmaaldrich.com/materials-science/micro-and-nanoelectronics/surfactants.html Others are available at: http://www.azonano.com/nanotechnology-videos.asp?cat=16 Ask the students to summarize and describe what they saw in the video(s). ACTIVITY: • Introduce the concepts of bottom-up and top-down fabrication using the presentation included with this teaching module, “Top-down and Bottom-Up Fabrication.” This presentation contains slides for the teacher to use/follow during the lecture. Due to copyright issues, we are only able to provide slides with images in pdf format. Nonetheless, we also provide the text only slides in PowerPoint format. The teacher may consider putting together his/her own slides using this presentation as a guide. Then divide the class into two groups: top-down and bottom-up. Each group should create a

simple shape, a 5-point star for instance, one group uses top-down methods and the other uses a bottom-up technique. The top-down group should be provided with a single sheet of paper from which they must cut the shape, while the bottom-up group should be provided with very small pieces of paper (i.e. atoms or molecules) from which they will piece together the shape. Students should re-explain their respective method to the class and discuss the advantages and difficulties of the technique. For example, top-down fabrication results in waste materials; bottom-up synthesis requires some form of adhesion mechanism. •

Watch the video at: http://ca.youtube.com/watch?v=zqyZ9bFl_qg, which gives a fantastical representation of “bottom-up” fabrication (file is large, so allow for download time). Ask the students to draw and/or describe something they would like to make using the nanofactory. What atoms/molecules would be required to fabricate their structure/device? Describe the order of processes for making the structure/device. For example, are there multiple components that will have to be fabricated first and then joined together? Ask the students to share their contributions to the class, and make a list on the board. Work with the students to rank the structures/devices in order of ease of fabrication via a bottom-up process. For example, a marble would be easy while an ipod would be difficult.

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Bonus activity appropriate for advanced/older students only: Ask the students to read the article at: http://pubs.acs.org/cen/coverstory/8148/8148counterpoint.html. This may be an appropriate homework assignment as the article is long. Alternatively, the article may be read and discussed in-class as a group. Questions about the article are provided in Homework #2 included in this teaching module.

CLOSURE: Ask the students to share the most interesting thing they have learned or seen from the lesson. They can turn in their one-sentence statements as they leave the classroom.

ASSESSMENT AND EVALUTION: The students will be using critical thinking skills to technically describe and form conclusions during the discussion periods. The in-class discussions can be used to assess/evaluate the students’ grasp of the concepts. Additionally, two homework assignments are provided for more concrete assessment. Rubric:

The students should be evaluated on following aspects.

Criteria 0 Clarity Did not participat e at all

Scores 1 Did not make logical sense

2 Clear statements very infrequently

3 Clear with fairly frequent unclear statements

Very few arguments presented Few examples

Arguments approximatel y half effective Several Examples

Arguments

Did not participat e at all

Examples

Did not participat e at all

No reasons for statements provided Very little or no examples

Rebuttals

Did not participat e at all

No arguments presented

Few counterarguments presented

Several counterarguments presented

Participatio n

Did not participat e at all

Very infrequentl y spoke

Infrequent participatio n

Occasional participation

Total= _____/25 = _____%

4 Mostly clear statements with infrequent confusion Arguments mostly effective

5 Clear statements and arguments

Good amount of examples

Large amount of examples

Good amount of counterarguments presented Frequent participatio n

Many effective counterarguments

Arguments very effective

Participation often

“What is Nanotechnology?” Homework Assignment #1 Define the following words or terms: 1. Nanoscale

2. Nanometer

3. Nanoparticles

4. Nanotubes

5. Thin films

6. Nanocomposites

7. Nanostructured bulk materials

Answer the Following Questions: 8. What two characteristics help define nanotechnology?

9. Name and explain how four current applications are benefiting from nanotechnology.

10. Give a specific example of a nanostructure used in a real application.

11. Describe a potential risk or negative consequence of nanotechnology.

“What is Nanotechnology?” Homework Assignment #1 Answer Key Define the following words or terms: 1. Nanoscale: Describes the length scale at which unique phenomena/behavior arises due to reduced dimensionality measured in nanometers (approximately 1 – 100 nm). 2. Nanometer: One-billionth of a meter 3. Nanoparticles: A structure which measures between approximately 1 and 100 nm in all three dimensions. 4. Nanotubes: A structure which measures between approximately 1 and 100 nm in two dimensions. Also refers to the nanostructure as being a hollow cylinder. 5. Thin films: A structure which measures between approximately 1 and 100 nm in only one dimension. 6. Nanocomposites: A material in which nanoscale inclusions are dispersed. 7. Nanostructured bulk materials: A material which has structural characteristics that measure nanoscale dimensions. Answer the Following Questions: 8. What two characteristics help define nanotechnology? Length scale: 1-100 nm Property change such as mechanical, chemical, electrical, optical, thermal, etc. 9. Name and explain how four current applications are benefiting from nanotechnology. Students may give a wide variety of examples. 10. Give a specific example of a nanostructure used in a real application. Students may give a wide variety of examples such as silver nanoparticles for anti-bacterial applications, thin film coatings for stain-resistance of textiles, nanocomposites for gas barrier properties of balls, etc. 11. Describe a potential risk or negative consequence of nanotechnology. Students may give a wide variety of examples including but not limited to: unknown environmental hazards or health effects, unfair advantage in sports, etc.

The Drexler-Smalley Debate Homework #2 1. Briefly describe K. Eric Drexler’s vision for the future of nanotechnology.

2. What part of Drexler’s vision does Richard Smalley feel is not possible? List three arguments that Smalley makes to try to prove his point.

3. Drexler states that “U.S. progress in molecular manufacturing has been impeded by the dangerous illusion that it is infeasible.” With this statement in mind, do you think Smalley’s attempt to maintain a realistic attitude towards nanotechnology could hurt the potential to develop nanomachines as new technology becomes available?

4. The types of manufacturing that Drexler envisions are currently used in industry at the microscale level. One example is known as MEMS (micro-electro-mechanical systems) technology as described here: http://www.memx.com/technology.htm. Read this web page and describe how MEMS is similar to and different from Drexler’s nanomachines and why MEMS is currently more feasible than nanomachines or nanobots.

The Drexler-Smalley Debate Homework #2 Answer Guide Students may give a wide variety of answers to these questions. Below are some expected discussion points. 1. K. Eric Drexler envisions molecular manipulators that can precisely position atoms and molecules to achieve pre-defined chemical reactions. This allows for the rapid, customizable creation of complex structures with no waste products. 2. Richard Smalley believes that the nanomachines would be incapable of controlling individual atoms in the manner that Drexler states. Smalley states that (1) the number of “fingers” needed to precisely control atoms and molecules is too large, limiting the space in which the nanostructures can be placed. (2) If such “fingers” are not used, enzyme-like structures must be used to control the chemistry, much like in biological self-assembly. This requires that the reactions occur in water, which limits the variety of the output. (3) Precise chemistry cannot be created simply by placing two atoms or molecules next to each other without more complex guidance. 3. Some student might argue that you cannot totally discount the feasibility of a process when new technology is developed as rapidly as it is today, while others may state that Drexler is relying too heavily on current applications of nanotechnology to validate the possibility of future success when such a grand vision has not been physically realized with current nanotechnology strategies. 4. MEMS operates on the microscale (one millionth of a meter) versus nanomachines which are orders of magnitude smaller. Top-down fabrication is typically used for MEMS technologies whilst bottom-up fabrication may be more prevalent in the building of Drexler’s nanomachines. Both MEMS and nanomachine systems are concerned with creating structures/devices that serve particular functions and/or carry out intricate operations at miniaturized scales. However, MEMS is currently the more feasible approach because fabrication methods have been proven (largely because the microelectronics industry has perfected them), and therefore microscale machines may be more easily manufactured. Moreover, complexities concerned with manipulating individual atoms/molecules are avoided.