## The Power of Graphene

This lesson focuses on graphene and its electrical properties and applications. Students work in teams to hypothesize and then test whether graphene is an electrical conductor or insulator. They build a simple circuit using everyday items, and create a graphene sample using soft pencils on paper.

• Learn about circuits, insulators, and conductors.
• Learn how engineering can help solve society’s challenges.
• Learn about teamwork and problem solving.

Age Levels: 8 – 18

### Build Materials (For each team)

Required Materials

• Pencils
• Paper
• LED light
• 330 Ohm resistor (to prevent the LED light from burning out)
• Insulated connectors
• 9 Volt battery
• Insulating gloves

### Testing Materials

• Use build materials

#### Testing Materials & Process

Materials

• Use build materials.

Process

Instruct students to consider their challenge, and as a team theorize whether they think graphene would conduct or insulate electric current. They should document their hypotheses.

Teams test their hypotheses by setting up a simple circuit using connectors, an LED bulb, a battery, and other materials. They will create a working circuit first and see if they can light the bulb. Then, they should adjust their circuit so that the current must flow through a piece of paper with pencil markings rubbed onto it. (Instruct students to NOT attach the connectors to the pencil lead that is still in a pencil.) Students then compare their hypotheses to their actual results.

Safety Notice

Students should NEVER attempt to run electric current through a pencil as this can cause the wood to catch on fire; this activity should be supervised by teachers at all times. Students should wear insulating gloves when handling the connector clips, and attach the battery last.

#### Engineering Design Challenge

Design Challenge

You are a team of engineers given the challenge of learning about the power of graphene by building a working simple circuit using an LED light, battery and resistor.

Criteria

• Circuit must use an LED light, battery and resistor
• Test graphene on a piece of paper

Constraints

• Use only the materials provided.

#### Activity Instructions & Procedures

1. Break class into teams of 3-4.
2. Hand out the The Power of Graphene worksheet, as well as some sheets of paper for sketching designs.
3. Discuss the topics in the Background Concepts Section. Consider asking the students what they know about insulators and conductors and whether they think graphene would behave in either way.
4. Review the Engineering Design Process, Design Challenge, Criteria, Constraints and Materials.
5. Provide each team with their materials.
6. Explain that students must build a working circuit using an LED light, battery, and resistor, and then test graphene on a piece of paper to see if it completes the circuit.
7. Announce the amount of time they have to build and test their circuit (1 hour recommended).
8. 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.
9. Instruct students to consider their challenge, and as a team theorize whether they think graphene would conduct or insulate electric current. They should document their hypotheses.
10. Teams test their hypotheses by setting up a simple circuit using connectors, an LED bulb, a battery, and other materials. They will create a working circuit first and see if they can light the bulb. Then, they should adjust their circuit so that the current must flow through a piece of paper with pencil markings rubbed onto it. (Instruct students to NOT attach the connectors to the pencil lead that is still in a pencil.) Students then compare their hypotheses to their actual results. If you like, you can give students other items to test if they are conductors or insulators.
11. As a class, discuss the student reflection questions.
12. For more content on the topic, see the “Digging Deeper” section.

Extension Idea

Based on the results of the testing, ask the teams to brainstorm how graphene might be used to revolutionize a product. They should consider how lightweight and flexible the material is and prepare a brief presentation to the class about how graphene might either improve a product or allow the product to be made smaller.

Student Reflection (engineering notebook)

1. How accurate was your hypothesis compared to what happened?
2. What surprised you about what you saw?
3. What new application for graphene that was presented by a team in your classroom was the most interesting to you?Why?
4. Do you think that engineers have to keep track of what is happening in research in order to improve on existing products or methods?
5. When a product is improved based on new research or materials, who do you think should be credited or compensated for the enhanced product?
6. Did you think that working as a team made this project easier or harder?  Why?

#### 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.

#### Engineering Design Process

Divide into teams
Review the challenge and criteria constraints
Brainstorm possible solutions (sketch while you brainstorm!)
Choose best solution and build a prototype
Test then redesign until solution is optimized
Reflect as a team and debrief as a class

#### Background Concepts

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.

What is Graphene?

Graphene is a one atom thick, two dimensional material which consists of carbon atoms densely packed into a honeycomb-like crystal lattice. This is known as a single layer graphene. Bi-layer and multi-layer graphenes have also been synthesized in the laboratory. Graphene exhibits very interesting electrical, optical, mechanical, thermal and other properties. Electrically, it is a semimetal or a semiconductor with zero bandgap. Graphene shows a very low resistivity, for example, only 10-6Wcm at room temperature. A single layer of graphene film is highly opaque, it absorbs only 2% of the white light. The mechanical properties are exceptional.

The interesting properties of graphene have led to an explosion of research recently in their synthesis, characterization of their properties, and development of applications. Promising applications include electronic devices, transparent electrodes for solar cells and plasma displays, composites, energy storage devices, and chemical and biological sensors.

Currently researchers are able to produce graphene by reducing graphene oxide. This chemical synthesis approach can now yield gram quantities of the material. It is also possible to deposit a single layer of graphene on a silicon wafer. A technique called chemical vapor deposition allows growth of single or multilayer graphene at 900-1000º C.

Nobel Prize for Graphene Research

Two researchers recently received the Nobel Prize in physics for their work on graphene! In 2010 Andre Geim and Konstantin Novoselov jointly shared the award “for groundbreaking experiments regarding the two-dimensional material graphene.” The researchers, along with several collaborators, were the first to isolate the layers of carbon from the material graphite, which is used in pencil “lead.”

Applications

From medicine to electronics, many governments and organizations are currently dedicating efforts to the application of graphene. This field has changed dramatically in a short period of time, making graphene a material that is changing many industries.

What is a Simple Circuit?

A simple circuit consists of three minimum elements that are required to complete a functioning electric circuit: a source of electricity (battery), a path or conductor on which electricity flows (wire) and an electrical resistor (lamp) which is any device that requires electricity to operate. The illustration below shows a simple circuit containing, one battery, two wires, a switch, and a bulb. The flow of electricity is from the high potential (+) terminal of the battery through the bulb (lighting it up), and back to the negative (-) terminal, in a continual flow when the switch is in the on position so current can flow

Schematic Diagram of a Simple Circuit

The following is a schematic diagram of the simple circuit showing the electronic symbols for the battery, switch, and bulb.

#### Dig Deeper

Internet Connections

• Nanotechnology For Dummies (ISBN: 978-0470891919)
• Nanotechnology: Understanding Small Systems (ISBN: 978-1138072688)

Writing Activity

Write an essay or a paragraph about how advances in nanotechnology have changed the field of electronics or medicine.

### Alignment to Curriculum Frameworks

Note: Lesson plans in this series are aligned to one or more of the following sets of standards:

#### 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

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

• Understanding 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 challenges

CONTENT STANDARD G: History and Nature of Science

As a result of activities, all students should develop understanding of

• Science as a human endeavor

#### 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

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

• Understandings about science and technology

#### National Science Education Standards Grades 5-8 (ages 10-14) (cont.)

CONTENT STANDARD F: Science in Personal and Social Perspectives

As a result of activities, all students should develop understanding of

• Personal health
• Risks and benefits
• Science and technology in society

CONTENT STANDARD G: History and Nature of Science

As a result of activities, all students should develop understanding of

• Science as a human endeavor
• Nature of science
• History of science

#### 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

CONTENT STANDARD B: Physical Science

As a result of their activities, all students should develop understanding of

• Structure and properties of matter

CONTENT STANDARD E: Science and Technology

As a result of activities, all students should develop

• 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

CONTENT STANDARD G: History and Nature of Science

As a result of activities, all students should develop understanding of

• Science as a human endeavor
• Nature of scientific knowledge
• Historical perspectives

#### Next Generation Science Standards Grades 2-5 (Ages 7-11)

Matter and its Interactions

Students who demonstrate understanding can:

• 2-PS1-2.  Analyze data obtained from testing different materials to determine which materials have the properties that are best suited for an intended purpose.
• 5-PS1-1.  Develop a model to describe that matter is made of particles too small to be seen.
• 5-PS1-3.  Make observations and measurements to identify materials based on their properties.

Engineering Design

Students who demonstrate understanding can:

• 3-5-ETS1-2.Generate and compare multiple possible solutions to a problem based on how well each is likely to meet the criteria and constraints of the problem.
• 3-5-ETS1-3.Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved.

#### 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 2: Students will develop an understanding of the core concepts of technology.
• Standard 3: Students will develop an understanding of the relationships among technologies and the connections between technology and other fields of study.

Technology and Society

• Standard 5: Students will develop an understanding of the effects of technology on the environment.
• Standard 6: Students will develop an understanding of the role of society in the development and use of technology.

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 13: Students will develop abilities to assess the impact of products and systems.

#### Student Worksheet

Research Phase

Hypothesis

As a team, decide whether you think graphene (in ordinary pencil “lead”) would be an electrical conductor or an insulator.  Write a supporting paragraph for your hypothesis on the other side of this paper.

Test

Now, test your hypothesis!  Set up a simple circuit using connectors, an LED bulb, a battery, and other materials provided by your teacher. You’ll create a working circuit first — see if you can light the bulb!  Then, adjust your circuit so that the current must flow through a paper that you have rubbed lots of pencil onto.  (Do NOT attach the connectors to pencil lead that is still in a pencil.)  If you like, you can test other items provided by your teacher to see if they are conductors or insulators.

Observation and Results

Observe and discuss what happened — if anything — and compare the results with your team’s hypothesis.

Application Development

Based on the result of your experiment, as a team brainstorm on how graphene might be used to revolutionize a product.  Consider how lightweight and flexible the material is and prepare a brief presentation to your class about how graphene might either improve a product or allow the product to be made smaller.

Presentation and Reflection Phase

Present your original hypothesis and experiment observations to the class along with your team’s product application.  Listen to the presentations of the other teams and then complete the reflection sheet.

Reflection
Complete the reflection questions below:

1. How accurate was your hypothesis compared to what happened?

2. What surprised you about what you saw?

3. What new application for graphene that was presented by a team in your classroom was the most interesting to you? Why?

4. Do you think that engineers have to keep track of what is happening in research in order to improve on existing products or methods?

5. When a product is improved based on new research or materials, who do you think should be credited or compensated for the enhanced product?

6. Did you think that working as a team made this project easier or harder? Why?

#### Translations

Lesson Plan Translation