The Power of Graphene

The Power of Graphene

Lesson Focus

This lesson focuses on graphene and its electrical properties and applications. Students learn about nanotechnology and how engineers can harness the differences in how materials behave when small to address challenges in many industries. 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. They observe what they see, extrapolate to broader applications, present their ideas to the class, and reflect on the experience. 

Lesson Synopsis 

The “Power of Graphene” lesson explores graphene and its electrical properties and applications at the nano scale. Students work in teams to test graphene using a simple circuit set up and consider how this remarkable material is impacting many industries. Teams evaluate their test results, develop new theoretical applications for graphene, present their ideas to the class, and reflect on the experience. 

Age Levels 

8-18.

Learning Objectives 

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

Anticipated Learner Outcomes 

As a result of this activity, students should develop an understanding of: 

• graphene
• circuits, conductors and insulators
• nanotechnology 
• teamwork.

Lesson Activities 

Students explore nanotechnology and the material graphene in terms of its ability to conduct electricity and its impact on many industries and products. Students test graphene to see if it will be an insulator or conductor in a simple circuit, and develop hypothetical applications for graphene that would revolutionize a product or system. Teams present their ideas to the class and reflect on the experience.  

Resources/Materials 

• Teacher Resource Information 
• Student Resource Information 
• Student Worksheet (included here) 

Alignment to Curriculum Frameworks 

See the included curriculum alignment information. 

Internet Resources 

• TryEngineering (www.tryengineering.org) 
• TryNano (You’re already here!) 
• National Nanotechnology Initiative (www.nano.gov) 
• Dartmouth Electron Microscope Facility Images (www.dartmouth.edu/~emlab/gallery) 

Supplemental Reading 

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

Optional Writing Activity 

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

Safety Notice

Students should NEVER attempt to run high electric currents through a pencil as this can cause combustion of the pencil materials; 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. 

For Teachers: 

Lesson Goal 

The “Power of Graphene” lesson explores graphene and its electrical properties and applications at the nano scale. Students work in teams to test graphene using a simple circuit set up and consider how this remarkable material is impacting many industries. Teams evaluate their test results, develop new theoretical applications for graphene, present their ideas to the class, and reflect on the experience. 

Lesson Objectives 

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

Materials 

• Student Resource Sheets 
• Student Worksheets 
• One set of materials for each group of students:
  • pencils 
  • paper
  • LED light
  • 330 Ohm resistor (to prevent the LED light from burning out)
  • insulated connectors
  • 9 volt battery.  

Procedure 

1. Show students the various Student Reference Sheets. These may be read in class, or provided as reading material for the prior night’s homework.
2. To introduce the lesson, consider asking the students what they know about insulators and conductors and whether they think graphene would behave in either way. 
3. If internet access is available, have students review the resources at www.trynano.org. The site will provide additional background information about nanotechnology and the industries where it is having great impact. 
4. Teams of 3-4 students will consider their challenge, and as a team theorize whether they think graphene would conduct or insulate electric current. 
5. Teams next build a working circuit using an LED light, battery, and resistor, and then test graphene (and other materials if you would like to extend the activity) on a piece of paper to see if it completes the circuit. 
6. Teams observe what happened, compare their hypotheses to the actual results, complete a reflection sheet, and present their experiences to the class.

Time Needed 

One or two 45 minute sessions 

Tips 

• Have students explore different types of pencil leads.
• Explore how the line shape (curved, straight, etc.) and length affect results.

For Students: 

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 packed into a honeycomb-like crystal lattice. This is known as a single layer graphene. Bilayer and multilayer 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^-6 ohm cm at room temperature. A single layer of graphene film is fairly transparent only absorbing about 2% of white light passing through it. 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 single layer of graphene on a silicon wafer. A technique called chemical vapor deposition allows growth of single or multilayer graphene at 900-1000 ºC. 

Nobel Prize for Graphene 

Two researchers 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.