NANO AT HOME: Experiments That You Can Try
PLEASE NOTE: The Center for Nano- and Molecular Science and Technology (CNM) at The University of Texas at Austin (UT-Austin) cannot guarantee the accuracy or the safety of these activities. Some of these activities might pose safety hazards for young children, and all activities should be performed under the supervision of a responsible parent, teacher or adult. The CNM and UT-Austin do not assume any responsibility for these activities or their results. If you have questions, corrections, or comments please do not hesitate to contact the CNM.
Nanoscience isn’t just for the laboratory! Many objects in nature and even in your own home exhibit nanoscale phenomena. Here are some examples of everyday nano-wonders:
Stick around a while and learn about the nanoscale…
Here in Austin, Texas, it is not that unusual to see an occasional gecko. Gecko feet have an amazing ability to stick on-demand to a variety of surfaces – even glass! Their climbing ability appears to be related to hair-like structures on their toes. Those “hairs” split and end in tips that are only about 200 nanometers across. To view the individual hairs, you would need a powerful electron microscope like the ones used in the CNM. Scientists have learned how to generate textured surfaces that act like gecko’s feet and have even built robots with “gecko-inspired feet” that can climb up walls.
Ewww! Particles of the common cold virus are about 30 nanometers in size. It is not recommended that you deliberately produce these nanostructures.
Do NOT try this at home
If you were take a large hammer and break open your computer and keep smashing until you get to the integrated circuits you would find…not much…because the nanoscale electrical components are very much smaller than what the human eye can see. However, you may have given yourself an excuse to buy a new computer after recycling what is left of the old one.
Time to come clean about nano
The leaves of some plants, such as the lotus, have nanostructures on their surfaces that make the leaves rough at an extremely small scale. This roughness decreases the ability of water and dirt to stick to the plant leaves. (The leaves in the lotus garden by the UT tower are quite clean.) Inspired by this natural nano-phenomenon, some fabrics are now treated with extremely small fibers to help them to repel water, dirt, and stains.
The next time you take a bath or wash dishes, look closely at the soap bubbles. Soapy water has no color, but bubbles show a swirling rainbow of colors by selectively reflecting light waves that are 400-800 nanometers long. When a colorful soap bubble loses its color just before popping, its wall is thinner than 25 nanometers. The same sorts of rainbow colors sometimes can be seen when petroleum products come into contact with water.
Peacocks’ feathers also appear iridescent because they have regularly spaced, tiny features that selectively reflect light.
Spectacular colors can be made by treating metals like titanium with heat or electricity to produce layers of metal oxides that are tens or hundreds of nanometers thick.
*NOTE: The colors described here are produced by a phenomenon known as light interference. Rainbows in the sky are produced by refraction of light.
Nano by fire
Many nanoscale structures are produced using the assistance of heat to break and reform chemical bonds in new arrangements. In a similar way, the heat from a candle flame converts some of the candle wax into soot particles, which are mostly composed of carbon. An object placed over a candle flame will collect these particles -many have sizes on the order of hundreds of nanometers.
When a pencil makes a mark on paper, tiny sheets of clay and graphite are rubbed from the pencil “lead” onto the paper fibers. Recently, scientists have repeatedly split stacked layers of graphite apart (like cutting a deck of cards) to isolate single-atom sheets of graphite. These single sheets, called graphene, have thicknesses of only a third of a nanometer – much thinner than the smallest piece of pencil dust. Other carbon structures resemble sheets of graphene that have been rolled into tubes and are called carbon nanotubes. Graphene sheets and carbon nanotubes conduct electricity, and are being studied at UT-Austin for use as extremely small electrical components.