 FPF Topics (proposed) < click to go to the Fun Physics Facts for the Family Demonstrations (proposed) page.
 FPF Topics 2 (proposed) < click to go to page 2 of the Fun Physics Facts for the Family Demonstrations (proposed).
Fun Physics Facts for the Family Demonstrations (proposed)
Below are a few of the possible topics for demonstrations that I may present at the Journey Museum. I have already written comprehensive solutions to all of these topics, so any demonstration may be presented at any time. Obviously I cannot do them all, so I will have to be selective for the presentations that I do give. Any requests?
Note: The rather cryptic discussions below are meant as a list of teasers for possible demonstrations, not as full accountings of those demonstrations.
We learn about Conservation of Angular Momentum and the Cat Reversal Reflex. Then we ask if an Astronaut can turn around in outer space without touching anything and without using her thrusters?
 The Mythical, Magical, Mystical Gyroscope and Antigravity
How does the gyroscope act like a mirror for forces? We investigate all of those bizarre behaviors of a gyroscope and how they are often misunderstood. We learn a very simple mechanism that explains the counterintuitive nature of the gyroscope, and we learn why the gyroscopic `antigravity' claims do not hold water.

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 Slow Down to Hurry Up, or Hurry Up to Slow Down?
Say you were driving down the Interstate highway and wanted to catch up to a car in front of you. Would you stomp on the gas pedal thereby speeding up or would you step on the brake thereby slowing down in order to catch the car in front of you? Remember your answer...
Space Shuttle Emergency Catch Up  How to do it? There has been an explosion on the Space Station. We may be their only hope for survival, so our Space Shuttle needs to catch up to the Space Station that is orbiting 5 minutes ahead of us (both are in the same orbit, with the Shuttle 5 minutes behind the Station). Does that mean we should fire our rockets to speed up (analogous to what we would do in a car on the highway in order to catch up to a car in front of us > stomp on the gas pedal)? Or does that mean we should fire our retrorockets to slow down (analogous to stepping on the brake in order to catch the car in front of us)? Boy, is this ever confusing...
 The Most Famous Equation in the World!
What is the basis behind Einstein's Amazing Equation: E=mc^2? This equation, the crown jewel of Einstein's theory, followed immediately from the mathematical machinery of Special Relativity. Numerous web sites, books, magazine articles, and PBS specials have discussed the meaning of E=mc^2 in terms of its conversion of a small amount of mass to a huge quantity of energy, but very few have talked about the underpinnings of this famous equation. From where does this famous equation stem? Do you have to understand all of Einstein's theory in order to understand E=mc^2? (Einstein derived his equation using the mathematical machinery of Special Relativity.) Here we provide a simple Newtonian explanation that allows for a derivation of Einstein's Special Relativistic E=mc^2 without the need for Special Relativity!
Have you ever tried to step out of the back of a small row boat onto a pier before? I have, with the following results ... whoops!
This cartoon illustrates Professor KickMe's illfated fishing expedition. Upon returning to the pier in his row boat, the Professor attempted to step out of the boat onto the pier, with dastardly results ... to quote the Professor, ``I was stepping out of my fishing trawler when someone moved the pier!''
(By the way, all motion is relative, according to Einstein.)
In the above cartoon, if you understand why Professor KickMe went into the drink, then you already know everything you need to fully understand the most famous equation in all of physics!

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The only concept that we need beyond Newtonian Mechanics is the idea that light carries momentum, an idea that James Clerk Maxwell originally proposed in the 1860s and Sir William Crookes invented the Crookes radiometer (pictured above) in 1873 to demonstrate. [The mechanism of the Crookes radiometer is still somewhat controversial, which we will discuss, and it was the Nichols radiometer that experimentally verified in 1901 that light possessed momentum.]
We derive E=mc^2 from classical concepts without the need for Special Relativity. We also show why this is possible, why it is possible to derive Einstein's equation without requiring Einstein's mathematics (the Special Relativity factors cancel out of the calculation).
 Moon Repulsion and Leap Seconds
If Conservation of Momentum is a Law, and Laws cannot be broken, then Why is the Moon Moving Away from Us? We will learn how the most common explanation for tides is not the whole story, and what is the whole story.
Counterintuitive Torques or Which Way Will the Roller Roll? Pulling on the cord might drag the roller to the right, or it might cause the roller to unroll the cord and thus roll to the left. Which is it?
 Hamilton's Beautiful Broome Bridge Equations and Spinors
ChargeParity (CP) Violation is The Most Shocking Experimental Discovery of the 20th Century, a century of amazing discoveries: superconductivity, Special Relativity, General Relativity, Quantum Mechanics, Black Holes, electronics, lasers, weak force, strong force, the Big Bang, etc. We will learn why the Nobel Prize winner Richard Feynman said that dancing girls predict the existence of antimatter.

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Homoclinic Tangles and Mobius Bands: Without that funny onesided band we would not have chaos.

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The phase portrait of the Lorenz Strange Attractor...
 The Topology of the Book, or Why the Gravity Probe B Failed?
A book tumbles around its Axis of Intermediate Moment. You can spin a book around its longest axis and its shortest axis, but you cannot spin it around its middle length axis. Why not? This simple demonstration goes a long way toward explaining why the Gravity Probe B has had such a difficult time observing the LenseThirring Effect (frame dragging).

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 Flight! How Is It Possible?
The three most common explanations of flight are incorrect. So, what is a more proper mechanism for how airplanes fly? Even Albert Einstein's intuition failed him at the start of WWI when he proposed an airplane wing design that was an utter disaster. The test pilot almost died on the maiden and only flight of Einstein's wing. Also, do you know how those dimples on golf balls work?
 Waves and What a Slinky toy can Teach Us
What happens when a wave propagating down a string, say a guitar string for example, or a sound wave traveling down an organ pipe, reaches the end of the the string? An extremely clever idea very simply explains the different phenomena of reflection.
In the above photograph Steve has shaken the end of the plastic Slinky placing a wave packet traveling to the left on the upper (farther away) side of the Slinky. This wave packet is about to encounter a boundary between itself (plastic Slinky) and a steel Slinky. What do you think happens at this boundary? Yup, that's correct: a portion of the wave packet "reflects" from the interface, rebounding in an inverted (bottom, or nearer, side) wave packet traveling to the right. (You may be wondering why the reflected wave is inverted, and this will be obvious to you when you have mastered the simple idea mentioned above.)
But now for the real question, what do you think would happen if Steve were holding the steel Slinky instead of the plastic Slinky and thus had just placed a wave packet traveling down the steel Slinky towards the boundary interface between the steel and plastic Slinkys? Would the wave packet be partially reflected? And if so, then what would be the nature of the reflected wave, would it be an inverted wave?
Direct current (DC) motors have split bushings that act to reverse the polarity of the current repeatedly as the rotor rotates in order to switch the poles of the electromagnets relative to the fixed magnets of the motor. In alternating current (AC) motors the bushings are not split because the current itself does the reversals. In light of these two alternatives, a DC motor with split bushings or an AC motor with alternating currents, then how does the following motor work? It appears to be a DC motor with unsplit bushings like the AC motor!
I measured the rotations of the screw pictured above at around 1750 rpm!
 Earnshaw's Theorem and Levitation
In 1840 Samuel Earnshaw published a theorem that shook the foundations of physics. His theorem stated that no static configuration of charges is possible. At the time, this put a major chink in the luminiferous aether through which light was supposed to travel, and about 60 years later his theorem made the first proposed model of the atom look like Plum Pudding. What does Earnshaw's Theorem say about levitation? We will learn a simple way to understand why Earnshaw's Theorem arises, but even more importantly we will learn that once a theorem always a theorem and thus always valid  on the other hand, there are more than one way to skin a theorem.
A cursory application of Earnshaw's Theorem says that magnetic levitation with permanent magnets is not possible. So how do we explain the above photograph?
 Sterling and Why We Can't Win
Can you explain the operation of the following motor? And it even runs just on the heat of your hand!

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 Not Only is Quantum Mechanics Strange, It is just Bizarre!
We've all heard about the nonlocality of Quantum Mechanics, that is, the socalled `actionatadistance' for entangled states, but how about actionatadistance before the fact! Yup, that's right, quantum systems somehow can predict what will occur before it happens...
In the Delayed Choice Quantum Eraser experiment photons somehow know whether a measurement is being made on their path and behave correspondingly before the decision to make such a measurement has been made!? The photons appear to either predict the future or, alternative, they reach back in time and change their history. In either case, it's just plainly bizarre.
 The Most Important Failed Experiment of All Time: MichelsonMorley
If you are standing on a railroad flatcar moving at 25 mph while I am standing on the ground beside the track throwing a baseball to you at 50 mph as you approach, then you see the baseball coming towards you at 75 mph. Makes perfect sense: if the flatcar is not moving then you would see the baseball coming at you at 50 mph, so with the flatcar moving towards me at 25 mph the net speed you would measure for the baseball is 50+25=75 mph. But if this is true then the speed of light as measured in the laboratory should depend upon whether the light is traveling in an EastWest direction or a NorthSouth direction due to the orbital speed of the Earth around the Sun. In the 1880s Michelson and Morley set out to verify this speed difference, but their experiment failed.
The Null Result of the MichelsonMorley experiment brought on a revolution in physics, culminating in Einstein's Special Relativity. From this experiment the mathematical machinery of Special Relativity is readily derived as well as all of the fascinating effects, such as Length Contraction, Time Dilation, and the Universe's Speed Limit: 299,792,458 m/s.
 How does one measure the local gravity acceleration?
Galileo was one of the most remarkable scientists of all time, his creativity surpassed by no one. He was about the first to perform bona fide experiments to verify physical facts. For instance, did you know that `a body in motion will tend to stay in motion' (Newton's First Law of Motion) was discovered by Galileo. He argued that on an inclined plane having a slight downhill slope a ball will slightly increase its speed (accelerate), while with a slight uphill slope the ball will ever so slightly decrease its speed (decelerate). So Galileo asked himself, "What happens if the incline is precisely horizontal?''

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 What is the Most Remarkable of All Mechanical Devices? This is my favorite: the Gyrocompass!
Most mechanical devices strive to eliminate friction as an unwanted hindrance on their operation. This device actually requires friction for its operation and as a consequence friction must be added to its bearings!
We all know about compasses. They sort of point in the direction of the North Pole. Well, actually, they point to the north magnetic pole which unfortunately does not coincide with the geographic North Pole. Thus we have to "correct" for the error (declination) in the direction pointed to by a compass. Do you know that there is a device that actually always points precisely North with no corrections required?

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 What do you think will happen in this experiment?
Or, why do radio towers and tall smoke stacks always seem to crumple in the middle when they fall over?
 The Beginnings of the Insurance Industry, or Did You Know that You Can Calculate Pi with a Needle?
3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679...
 How to measure something without "touching" it in any fashion (without "touching" to be explained)...
A Calculusbased Introduction:
Before we get started with this Surveying Thinking Problem, allow me to provide a short alternative introduction for those of you who have already studied Calculus. [You may skip to Heron's Formula if you wish.] This alternative describes what I think is one of the more remarkable relationships of Calculus, known as the First Fundamental Theorem of Calculus, that makes a connection between the derivative and the integral. In a fashion, it says that integration "undoes", or is the inverse, of differentiation, and vice versa. In one dimension, the First Fundamental Theorem of Calculus equates an integration of the derivative of a function over an interval to the function value at a single point (an infinite summation in 1D equated to a single value in 0D). When extended into two dimensions, the analogous theorem is known as Green's Theorem. It equates a double integration of the partial derivatives of a function over a region to a line integral of the function along the boundary line of that region (summation in 2D equated to a sum in 1D). And in 3space this concept generalizes to the socalled Divergence Theorem that equates a triple integral of the divergence (derivative) of a function over a volume to a double integral of the function over the boundary surface of that volume (sum in 3D equated to a sum in 2D). And the Divergence Theorem is a special case of the more general 3dimensional Stokes's Theorem.
From an alternative point of view, the Divergence Theorem in 2dimensions is equivalent to Green's Theorem, and Green's Theorem in 1dimension is equivalent to the First Fundamental Theorem of Calculus.
The recurring theme in the above dimensional generalizations is that a summation (integration) of the appropriate derivative of a function in N dimensions is equated to a summation (integration) of the function in N1 dimensions. This shocking decrease in dimension leads to some remarkable results, as we shall see in a moment. But for now, just remember the recurring theme: a sum (integral) in N dimensions is equal to a sum (integral) in N1 dimensions. (It is this theme that produces the measurement without "touching".)
Heron's Formula:
Say we wish to determine the area of a triangle. The standard high school geometry formula is A=(1/2)Bh where B is the length of the base and h is the length of the altitude to that base. The altitude is an "internal" measurement for the triangle, it requires "going inside" the triangle in order to find its value. Other formulae exist that utilize trigonometric functions of the angles of the triangle. Once again, an angle is an "internal" measurement, in that one must sweep across the interior of the triangle in order to measure the angle. If we were to employ Calculus to measure the area of a triangle, once again we would divide up the interior into rectangles and sum the areas of those rectangles. In the limit of an infinite number of infinitesimally narrow rectangles, this sum becomes the triangle's area. So, even the standard area measurements of Calculus require "internal" measurements.
In fact, all triangle area formulae require some form of "internal" measurements, with the single exception of what is known as Heron's Formula. Heron's Formula gives the area of a triangle only requiring the lengths of the triangle's sides, no angles nor other types of internal measurements are needed. Now this should be surprising to you on two fronts. First of all, we are measuring the interior of a triangle but without actually going "inside" the triangle. It is a form of measurement of the interior without actually having to make a measurement over said interior, that is, it is measurement without "touching". And secondly, we can draw two triangles having entirely different areas but the same perimeters. Since Heron's Formula relies on the perimeter length, how can it possibly determine the area of a triangle if two triangle's with the same perimeter lengths have entirely different areas?
Nevertheless, it's true, we can measure the area of a triangle without any "interior" measurements. Say we wish to survey a pasture, but we don't have a digital laser theodolite at our disposal. The theodolite would measure the angles of a triangle with great accuracy, but without one we would be reduced to using a dime store protractor. Our angle measurements would therefore be prone to fairly large errors. And when one makes a measurement on an angle that is in error by say 1 degree, the pieshaped area corresponding to this angle error when we get out to a distance of 600 yards is rather significant. Instead of the theodolite, we rather have a perambulator or perhaps even a laser rangefinder used in archery target shooting. Can we just measure the sides of the triangle using the perambulator or laser rangefinder and still be able to calculate the area?
Sandy holding a target for the laser rangefinder. And below are the measurements made... (notice that many of the angles are not 90 degrees)

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From these data the area of the pasture was calculated to be 58.9 acres.
The PDF file, , for this problem includes the Heron's Formula approach to surveying a pasture. The original proof of Heron's Formula was by means of Euclidean geometry is also given. It is a truly Sherlockian proof, apparently roaming around getting nowhere fast until the very last step when everything mysteriously falls into place. We include this 24 page romp through much of Euclidean geometry. But we also derive Heron's Formula using Vector Algebra, a strategy that is both concise (2 pages) and provides intuition into why Heron's Formula is true in the first place, something that is not forthcoming from the Euclidean proof.
And now for the real shocker > Okay, so we now understand that the interior area of a triangle can be determined without having to make any measurements on the interior of said triangle, but would you be shocked to learn that this statement is true not only for triangles with straight sides but also for most any general closed curve? Yup, consider a small, irregular shaped, pond. You can determine its area simply by making a 1dimensional measurement along the shore of the pond! You don't have to make any "interior" measurements to find its area. This is where the Calculusbased Introduction comes into play: this stunning result is a consequence of Green's Theorem, the theorem that equates a 2D integration (area computation) to a 1D integration (length computation). And the following mechanical device, known as a polar planimeter, implements Green's Theorem in gears and measures areas by following the 1dimensional border of those 2dimensional areas. (In other words, Green's Theorem allows an inherently 1dimensional measurement to calculate an inherently 2dimensional quantity, and this theorem is implemented mechanically using just a few gears.)

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(It is actually a theorem, so it is absolutely true, no questions asked. But the theorem runs so counter to everyone's intuition that it is often called a paradox.)
Would you believe it, a bowling ball (the continuous idealization of a bowling ball, that is) can be dissected into 4 pieces and a single point and those 5 partitions may be rearranged without overlapping or compressing any piece to form a golf ball (continuous idealization of such)? This is one of the most counterintuitive results in all of mathematics...why, even many mathematicians find this result extraordinary and unintuitive. We will follow a very simple argument using the Pigeonhole Principle and hotel rooms to gain insight into, and an understanding of, how the BanachTarski Paradox arises.
 We're Rich! We're RIch! We're Rich!
Isn't 5x13 > 8x8 ? If so, then We're Rich!
Below is a photograph of the implementation of the above strategy using thick card stock...
So, implement the above strategy in gold and we have gained a cubic inch of gold in the process! We're Rich! We're Rich! We're Rich!
 Do you know why it is so difficult to find a 4leaf clover? Can flowers really count?
If you have ever seen a field of clover, you may recall that all of them had three leaves. Perhaps you were lucky enough to find that famed 4leaf clover? Why are there so few 4leaf clovers? Let me tell you, it's not in the genes! There are no genes that can count to 3 but not 4, rather the reason is a purely mathematical one whose foundation is steeped in the difference between irrational numbers and rational numbers.
For the same mathematical reason, the above sunflower has 21 counterclockwise spirals and 34 clockwise ones.
 FPF Topics (proposed) < click to go to the Fun Physics Facts for the Family Demonstrations (proposed) page.
 FPF Topics 2 (proposed) < click to go to page 2 of the Fun Physics Facts for the Family Demonstrations (proposed).
Copyright (c) Craig G. Shaefer, all rights reserved.
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