Sunday, January 24, 2010

Kitchen Nanoscience

Nano is the scientific term meaning one-billionth (1/1,000,000,000). It comes from a Greek word meaning “dwarf.” A nanometer (nm) is one one-billionth of a meter. One inch equals 25.4 million nm. A sheet of paper is about 100,000 nm thick. A human hair measures roughly 50,000 to 100,000 nm across. Your fingernails grow one nanometer every second.

Nanoscale refers to things that are between 1 – 100 nanometers in size. A virus is about 70 nm long. A cell membrane is about 9 nm thick. Ten hydrogen atoms are about 1 nm. At the nanoscale, many common materials exhibit unusual properties, such as remarkably lower resistance to electricity, or faster chemical reactions. Nanoscience, nanotechnology and nanoengineering take advantage of these properties by working with individual molecules of material.

Not surprisingly, most Americans have a very poor grasp of nanoscience. In fact, according to NISE Net, the Nanoscale Informal Science Education Network,  many adults:
• Aren't sure whether atoms are composed of molecules or molecules are composed of atoms (they also confuse them with cells);
• Think everything microscopic is at the same scale
• Don't understand that matter is made up of particles, or believe there must be something in the space between particles;
•Believe that materials at the atomic or molecular level are simply shrunken versions of their real-world manifestations, with the same properties.

One of the ways NISE Net is working to change these misperceptions is by hosting events like NanoDays, which takes place in March. During NanoDays museums and schools around the country will hold demonstrations to explain nanoscience to kids and adults. Many of their past activities and educational materials are available at their website. Quite a few of these demonstrations are simple enough to do at home.

We did one very basic demonstration called Exploring Forces, which shows how the properties of materials differ according to scale using water and teeny-tiny containers. Although they weren't nanoscale, they did show -- as we saw in some of the documentaries we've been watching -- how the importance of forces like gravity change as quantities get smaller.

The experiment calls for doll-house teacups, but we used a Lego cup and goblet (natch!). After dipping the full-sized measuring cup into a bowl of water and pouring it out, we tried it with the Lego versions and found that it was harder to get the water to pour out. That's because the forces between the water molecules were stronger than gravity (this creates what is known as surface tension).

We also tried playing around with a variety of different sized measuring cups and spoons (including some very small "novelty" spoons, but only the very smallest (one "smidgen") exhibited surface tension, and only if you were very careful turning it over. However, I thought this was a fun and quick experiment to try.
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