Physics of the Future: How Science Will Shape Human Destiny and Our Daily Lives by the Year 2100

first to call attention to this new realm of physics was Nobel laureate Richard Feynman, who asked a deceptively simple question: How small can you make a machine? This was not an academic question. Computers were gradually becoming smaller, changing the face of industry, so it was becoming apparent that the answer to this question could have an enormous impact on society and the economy.
    In his prophetic talk given in 1959 to the American Physical Society titled “There’s Plenty of Room at the Bottom,” Feynman said, “It is interesting that it would be, in principle, possible (I think) for a physicist to synthesize any chemical substance that the chemist writes down. Give the orders and the physicist synthesizes it. How? Put the atoms down where the chemist says, and so you make the substance.” Feynman concluded that machines made out of individual atoms were possible, but that new laws of physics would make them difficult, but not impossible, to create.
    So ultimately, the world economy and the fate of nations may depend on the bizarre and counterintuitive principles of the quantum theory. Normally, we think that the laws of physics remain the same if you go down to smaller scales. But this is not true. In movies like Disney’s
Honey, I Shrunk the Kids
and
The Incredible Shrinking Man,
we get the mistaken impression that miniature people would experience the laws of physics the same way we do. For example, in one scene in the Disney movie, our shrunken heroes ride on an ant during a rainstorm. Raindrops fall onto the ground and make tiny puddles, just as in our world. But in reality, raindrops can be larger than ants. So when an ant encounters a raindrop, it would see a huge hemisphere of water. The hemisphere of water does not collapse because surface tension acts like a net that holds the droplet together. In our world, surface tension of water is quite small, so we don’t notice it. But on the scale of an ant, surface tension is proportionately huge, so rain beads up into droplets.
    (Furthermore, if you tried to scale up the ant so that it was the size ofa house, you have another problem: its legs would break. As you increase the size of the ant, its weight grows much faster than the strength of its legs. If you increase the size of an ant by a factor of 10, its volume and hence its weight is 10 × 10 × 10 = 1,000 times heavier. But its strength is related to the thickness of its muscles, which is only 10 × 10 = 100 times stronger. Hence, the giant ant is 10 times weaker, relatively speaking, than an ordinary ant. This also means that King Kong, instead of terrorizing New York City, would crumble if he tried to climb the Empire State Building.)
    Feynman noted that other forces also dominate at the atomic scale, such as hydrogen bonding and the van der Waals force, caused by tiny electrical forces that exist between atoms and molecules. Many of the physical properties of substances are determined by these forces.
    (To visualize this, consider the simple problem of why the Northeast has so many potholes in its highways. Every winter, water seeps into tiny cracks in the asphalt; the water expands as it freezes, causing the asphalt to crumble and gouging out a pothole. But it violates common sense to think that water expands when it freezes. Water does expand because of hydrogen bonding. The water molecule is shaped like a V, with the oxygen atom at the base. The water molecule has a slight negative charge at the bottom and a positive charge at the top. Hence, when you freeze water and stack water molecules, they expand, forming a regular lattice of ice with plenty of spaces between the molecules. The water molecules are arranged like hexagons. So water expands as it freezes since there is more space between the atoms in a hexagon. This is also the reason snowflakes have six sides, and explains why ice floats on water, when by rights it should sink.)
    WALKING THROUGH WALLS
    In addition to surface tension, hydrogen bonding, and van der Waals forces, there are also bizarre quantum effects at the atomic scale. Normally, we don’t see quantum forces at work in everyday life. But quantum forces are everywhere. For example, by rights, since atoms are largely empty, we should be able to walk through walls. Between the nucleus at the center of the atom and the electron shells, there is only a vacuum. If the atom were the size of a football stadium, then the stadium would be empty, since the nucleus would be