Why Is It So?

All of the weight of an object is at its center of gravity, says Miller. However, the center of gravity is not always at a point on the object. This leads to a few amazing balancing acts based on one principle: an odd-shaped system can stay in balance when its center of gravity is below the point of support.

Newton's First Law has two parts, and Professor Miller does his best to teach them together. His demonstrations include familiar magic tricks, such as the board under a sheet of newspaper.

F=ma is the standard shorthand for Newton's Second Law. But Professor Miller shows more depth, using two toy cars accelerating toward each other. He also expands F=ma into W=mg for falling bodies on Earth.

The Earth must recoil when Professor Miller jumps. It's the first of many illustrations that confirm, ""To every action there is always an equal and contrary reaction.""

From the outset, Miller emphasizes the difference between energy and momentum, first with the toy cars and then with a steel ball running a track. Miller then introduces the various kinds of energy.

Laws of motion and energy, discussed in earlier programs, converge in the real and virtual demonstrations Miller does on falling bodies and projectile motion. One principle says that horizontal motion does not affect vertical motion.

Anything can be a pendulum, says Professor Miller, and anything can oscillate. In fact, the period of a pendulum depends only on its length. Miller sets up demonstrations of various oscillating nodies. He also presents a puzzle about springs.

A family of 120 bore the name Bernoulli, and they were all geniuses. Miller points out how the Bernoulli principle affects our everyday lives: why two ships must not pass too closely on the sea, how a stream of air can suspend a ball above it, and many other things.

Miller's experiments on soap films show the pressure on soap bubbles, plus the fact that soap films always form a surface of least energy.

The atmosphere exerts an enormous force (15 pounds of pressure per square inch). Miller crushes steel cans, ruptures rubber, and breaks a wood plank with the atmosphere on his side.

Miller writes ""centrifugal"" in quotation marks because there is no force acting radially on rotating bodies. Balls, candles, hoops, and weights experience torques of which Miller says little.

All hoops roll alike, says Miller, and all disks beat all hoops when they race downhill. Thus Miller sends disks, hooops, and spheres rolling.

When a body is submerged in a liquid, it buoys up with a force equal to the weight of the liquid displaced. Miller shows this with a very clever set up involving cylinders submerged in water. He also points out a little of Archimedes' finest achievements. His greatest? Finding the ratio of volumes between a sphere, a cone, and a cylinder of equal height.

Blaise Pascal said liquids are incompressible. Any force exerted on a liquid is felt in all parts of the liquid without lessening of the force. Miller uses a pulley system to drive home that fact.

With a great many tools before him, Professor Miller sets out to prove that all tools and machines are linked to the two simplest: the lever and the inclined plane.