Overview
Description:
Nano is an interactive exhibition that engages family audiences in nanoscale science, engineering, and technology. Hands-on exhibits present the basics of nanoscience and engineering, introduce some real world applications, and explore the societal and ethical implications of this new technology.
Nano was created by the Nanoscale Informal Science Education Network (NISE Network) with support from the National Science Foundation. The Nano exhibition is intended for long-term display in museums across the United States, where it will engage tens of millions of people. Up to seventy copies of Nano will be fabricated; all copies will be identical and distributed to museum partners free of charge. The exhibition complements NanoDays events and other NISE Network educational experiences.
Checklist
Scientist reviewed?
Peer reviewed?
Visitor evaluation?
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Creative Commons
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Questions about Bonds in Build a Giant Carbon Nanotube Exhibit
We have received some questions asking why there aren't four bonds for each carbon atom in the "Build a Giant Carbon Nanotube" exhibit in the Nano mini-exhibition.
I am not a chemist, but hopefully I can answer this question and provide some background:
Carbon is quite flexible and has the ability to form several different typs of bonds (single, double, triple). Carbon also has the ability to bond in flexible ways and can form some very different structures using hybrid bonds. It's electronic configuration allows it to form different hybrid orbitals (allowing for rings, sheets, and chains).
• In diamond, each carbon atom has a single bond with 4 other carbon atoms in a tetrahedral crystalline structure. (sp3 hybrid bonded carbon atoms)
• In graphene, each carbon atom bonds with three other carbon atoms in sheets forming a hexagonal pattern, with weak Van der Waal's forces between the sheets --which is why graphite is soft as the sheets "slip' easily. (sp2 hybrid bonded carbon atoms)
• Carbon nanotubes are similar to individual graphene sheets in that each carbon atom bonds with three other carbon atoms but the sheet is rolled up onto itself to form a tube. (sp2 hybrid bonded carbon atoms)
The "Build a Giant Carbon Nanotube" exhibit is a simple ball-and-stick type of model representing how carbon atoms can form into a carbon nanotube. This type of ball-and-stick model design requires a specific number of holes at specified angles; given the constraints of this model, visitors are not able to create a diamond structure (which would need four holes at different angles).
Commercially available chemistry molecular model sets have several different approaches to this issue, including providing model atoms with different numbers of holes and angles, or flexible rather than stiff bonds.
We have several NISE Network programs that go more int the different forms and structures of carbon:
Cart Demo (including forms of Carbon poster)
http://www.nisenet.org/catalog/programs/forms_carbon
Nanotube model kits
http://www.nisenet.org/catalog/programs/nanotube_models
Also got a carbon atom question
We had a similar question arise at our exhibit. Here is the response we gave (this response was sent to a marketing department rep for our funder who received the question):
The person who snapped the photo of our Carbon Nanotube exhibit component is quite correct that carbon atoms have four bonding sites. However, carbon atoms are very flexible in how they bond. For example, carbon can bond to four other atoms (these are called single bonds), such as in methane, propane, aspirin, citric acid, and other molecules. This combination of four bonds is known as a sp3 carbon atom. It’s depicted in model form below (and attached), and we also have models in the exhibit that represent this four single-bond sp3 carbon atom.
In the case of carbon nanotubes, such as what is modeled in our exhibit, the four carbon bonds have a different arrangement. Two of the bonds are single and one is double, and they are arranged in a single plane. This is the same with other molecules like Buckyballs and graphene. This combination of three bonding sites is known as a sp2 carbon atom and is most often represented in models in the same way that it is in our exhibit. We use other similar, commercially available sp2 models to represent the carbon nanotubes and fullerenes present in our Super Small Matter Lab.
Student worksheet for nano mini-exhibition
A new student worksheet is now available for the nano mini-exhibition. School groups can use the worksheet to help them explore the exhibition as they go through it. An answer key is also provided for the teacher.