Small Wonders

Antibacterial properties of silver have long been known, but the greater efficiency of silver nanoparticles has resulted in an explosion of nano-silver products, including food storage, clothing, and first-aid. Visitors can see for themselves with flipbooks documenting bacterial growth on silver-treated medium and strawberries stored in nano-silver containers. A bubbling catalytic breakdown of hydrogen peroxide with either silver foil or powder demonstrates the power of increased surface area.

Disordered, or amorphous, metals are stronger, more durable, and more resistant to scratches and rust than steel, leading to their widespread application (for example, in the hinges of flip-open cell phones). In this activity, visitors see the amazing properties of the "Atomic Trampoline," as a metal ball continues to bounce off Liquidmetal ® long after a second ball bounced off steel has stopped. Our solid glass versus glass bead version illustrates the same principles of elasticity at the macro-scale.

Learn how the popular "Transitions" lenses work! Visitors use a real photochromic lens to observe how it darkens when exposed to ultraviolet, but not visible, light. Zooming into the nano-scale to take a closer look, visitors act as the sun and use a black light to change the shape of a model photochromic molecule. Visitors can also play with sample chips of photochromic dyes to see the range of colors now available. This activity helps to show how changing the shape of a molecule can also change its properties.

Toxic pollutants are infiltrating our soil and ground water, but this activity demonstrates new technology that uses nanoparticles of iron to combat this problem. First, visitors see that while macro-iron is too big to filter through sand, nano-iron can permeate through to reach groundwater. Next, visitors test the ability of nano-iron to reduce a blue starch/iodide complex, analogous to how it reacts with and neutralizes pollutants. Finally, visitors synthesize the whole process at the macro-scale using a model based on the popular The Price Is Right "Plinko" game.

No one wants the "lifeguard look" of white sunblock smeared on your nose. But sunblocks containing zinc oxide absorb ultraviolet light to protect your skin. New sunblocks with zinc oxide nanoparticles maintain this protection while disappearing into your skin. In this activity, visitors apply both traditional and nano-scale zinc oxide creams to paper to test the difference. A simple comparison of a dot pattern at different scales demonstrates how larger particles reflect more visible light.

A new method of cancer treatment using gold-coated silica nanoparticles could someday help patients say goodbye to the side effects of chemotherapy and radiation. By engineering the size of the nano-gold, scientists tune the particles to absorb light from infrared lasers and destroy a tumor. The challenge is that the light must pass safely through healthy tissue, but activate the nanoparticles in the tumor. In this activity, visitors tackle this problem, experimenting with LED flashlights and real nano-gold solutions to determine the optimal wavelength of light and particle size.

Have you ever seen water bead up on a leaf, or roll off a duck's back? Inspired by these natural phenomena, fiber scientists are using similar principles to create stain-resistant fabric. This activity explores the properties of 100% cotton Nano-Tex ® fabric, compared to regular 100% cotton fabric. By squirting liquids onto swatches of both fabrics, visitors observe how nano-scale changes in the cotton fibers can make a big difference in how these textiles perform. Visitors also toss beanbag "stains" at a macro-scale model of the fabric to see what is happening on the surface.

How small is small? We can see a butterfly with just our eyes. But what does it take to see the details of a butterfly's wing, the scales, or even the nano-scale photonic crystals? Playing a fun matching game, visitors appreciate the increasingly complex tools necessary to see a butterfly at the centi-, milli-, micro- and nanometer scales. In the second round of the game, identifying the progressively smaller parts of a cell phone reinforces visitors understanding of scale and introduces the importance of nanotechnology in their daily lives.