Air molecules stuck inside an inflated balloon are perpetually colliding with the inner surface of the balloon. Each collision provides a little push outward on the balloon. All the many collisions working together is what keeps the balloon inflated. To get a "feel" for what's happening here, add about a tablespoon of tiny beads to a large balloon (pellets, beans, BBs, grains of rice, etc., also work). Inflate the balloon to its full size and tie it shut. Hold the balloon in the palms of both hands and shake rapidly. Can you feel the collisions? As you shake the balloon wildly, the flying beads represent the gaseous phase. How should you move the balloon so that the beads represent the liquid phase? The solid phase?

Add a pinch of red Kool-aid crystals to a still glass of hot water. Add the same amount of crystals to a second still glass of cold water. With no stirring, which would you expect to become uniform in color first—the hot water or the cold water? Why?

A TV screen looked at from a distance appears as a smooth continuous flow of images. Up close, however, we see that this is an illusion. What really exists are a series of tiny dots (pixels) that change color in a coordinated way to produce images. Use a magnifying glass to examine closely the screen of a computer monitor or television set.

Who is the ultimate expert at nanotechnology?

What are the two main approaches to building nanoscale materials and devices?

What is the common name for oxygen oxide?

What pledge have many members of the American Chemistry Council made through the Responsible Care program?

The phase in which atoms and molecules no longer move is the (a) solid phase. (b) liquid phase. $(c)$ gas phase. (d) none of these

Throw ten coins onto a flat surface. Move aside all the coins that landed tails-up. Collect the remaining coins. After tossing them once again, remove all the coins that landed tails-up. Repeat this process until all the coins have been removed. Can you see how this relates to radioactive half-life? In units of “tosses” what is the average half-life of 25 coins? 50 coins? 1 million coins?

Rank these noble-gas atoms by their number of filled shells, from least to most: (a) argon, (b) radon, $(c)$ helium, (d) neon.

How soon will nanotechnology give rise to commercial products?

Rank the following in order from the most energy released to the least energy released: (a) uranium-235 splitting into two equal fragments, (b) uranium-235 splitting into three equal fragments, (c) uranium-235 splitting into 92 equal fragments.

Why are common names often used for chemical compounds instead of systematic names?

Of the atoms sodium, Na; magnesium, Mg; and aluminum, Al, one tends to lose three electrons, another tends to lose two electrons, and another tends to lose one electron. Rank these atoms in order of the number of electrons they tend to lose, from fewest to most.