Why are you required to have an item in the microwave oven while it is operating…

Why are you required to have an item in the microwave oven while it is operating?

When a microwave oven is cooking food, electrons move rhythmically back and forth inside the magnetron tube and create the microwaves. These microwaves flow through a metal pipe and into the cooking chamber, where they are absorbed by the water in the food and thus heat the food (the twisting back and forth of the water molecules, described elsewhere on this page, not only heats the food—it also absorbs the microwaves). If there is no food in the cooking chamber, the microwaves build up in the cooking chamber until they are so intense that large numbers of them flow backward through the pipe to the magnetron. These microwaves reenter the magnetron and disrupt the motion of electrons inside it. The magnetron begins to misbehave and can be damaged as a result. To avoid such damage, you want to be sure that there is something in the cooking chamber to absorb the microwaves before they return to the magnetron and cause trouble. In short, don’t run the microwave empty for any long periods of time.

During a total solar eclipse, does the moon make first contact with the sun on t…

During a total solar eclipse, does the moon make first contact with the sun on the eastern limb or the western limb? Can you explain this to me?

The moon orbits the earth from west to east. By that, I mean that if the earth were to stop turning, the moon would then rise in the west and set in the east. During a total solar eclipse, the moon is drifting directly in front of the sun. Since the moon moves from west to east, it will first block the western edge of the sun, the western limb. In contrast, during a total lunar eclipse, the moon is drifting into the earth’s shadow. Since it is moving from west to east, its eastern edge will enter the shadow first.

Is it possible to create a “fog” in a small enclosed area without using dry ic…

Is it possible to create a “fog” in a small enclosed area without using dry ice or ultrasound?

The two techniques you mention, dry ice and ultrasound, are both intended to make tiny droplets of water in the air, effectively producing an artificial cloud. While I can’t think of any better ways to make such water droplets, I can think of ways to make fogs of other materials. Tiny particles of any clear material will work because what you are seeing is the random scattering of light as it’s partially reflected from the front and back surfaces of clear particles. I’d suggest a chemical process that produces tiny clear particles. The easiest one I can think of is to place a dish of household ammonia (ammonium hydroxide—ammonia gas dissolved in water) and a dish of hydrochloric acid (hydrogen chloride gas dissolved in water, sold as muriatic acid by hardware stores) in your enclosed area. The two gases will diffuse throughout your enclosure and react to form tiny clear particles of ammonium chloride. The enclosure will fill with a dense white fog. The particles are so small, that they will remain in the air for a very long time, but they will eventually settle on surfaces and leave a white powdery residue. So, unlike a water fog, this chemical fog is a little messy. You shouldn’t breathe the fog, either.

How do color-changing eyeglasses work?

How do color-changing eyeglasses work?

These eyeglasses are made from a special photochromic glass that contains about 0.01% to 0.1% silver halide crystals. These crystals are transparent and so small that they leave the glass almost perfectly clear. But when the glasses are exposed to bright sunlight, which contains substantial amounts of ultraviolet light, the silver ions in those crystals are reduced to silver atoms and begin to form tiny silver particles inside the glass. Like the particles that form in black and white photography, these silver particles are so jagged and imperfect that they’re light absorbing rather than shiny. The glasses thus darken when exposed to sunlight. But when the eyeglasses are returned to the dark, the halogen gas atoms recombine with the silver atoms and reform the silver halide crystals. The eyeglasses once again become clear. Incidentally, the glasses can also be rendered clear by exposing them to elevated temperatures, so a short time in the oven should help to clear them up if darkness alone doesn’t do the trick. That assumes, of course, that you don’t melt the frames, overheat the glass, or expose the glass to sudden thermal shocks.

What would happen if you saturated the uranium side of a fusion bomb with cobalt…

What would happen if you saturated the uranium side of a fusion bomb with cobalt? I think it would destroy our planet.

A fusion bomb, also known as a thermonuclear or hydrogen bomb, releases enormous numbers of fast-moving neutrons. Neutrons are uncharged subatomic particles that are found in the nuclei of all atoms except the normal hydrogen atom. A normal cobalt nucleus contains 32 neutrons and is known as cobalt 59 (for its 59 nuclear particles: 32 neutrons and 27 protons). When a neutron collides with a cobalt 59 nucleus, there is a substantial probability that the cobalt 59 nucleus will capture it and become cobalt 60 (for its 60 nuclear particles: 33 neutrons and 27 protons). Cobalt 60 is radioactive—it falls apart spontaneously with a 50% probability each 5.26 years. When a cobalt 60 nucleus decays, it begins by emitting an electron and an antineutrino to becomes nickel 60 (for its 60 nuclear particles: 32 neutrons and 28 protons). But this nickel 60 has extra energy in it and it soon emits two high-energy gamma rays (electromagnetic particles, with more energy than x-rays) to become normal nickel 60, a common form of the nickel atom. A fusion bomb containing cobalt 59 could be expected to make lots of cobalt 60, which would then undergo this radioactive decay over the next few decades, releasing gamma rays as it does.

So a fusion bomb containing cobalt would release a large amount of cobalt 60 into the environment. This would certainly give the bomb long lasting radioactive fallout that would make it much more damaging to the environment than a pure fusion bomb would be. Whether it would destroy the planet, I can’t say. The bomb’s explosion wouldn’t be any more destructive, but its long-term toxic effect to animals and plants certainly would be.

There is a story circulating by email about a 26 year old man who heated a cup o…

There is a story circulating by email about a 26 year old man who heated a cup of water in a microwave oven and had it “explode in his face” when he took it out. He suffered serious burns as a result. Is this possible and, if so, how did it happen? — JJ, Kirksville, Missouri

Yes, this sort of accident can and does happen. The water superheated and then boiled violently when disturbed. Here’s how it works:

Water can always evaporate into dry air, but it normally only does so at its surface. When water molecules leave the surface faster than they return, the quantity of liquid water gradually diminishes. That’s ordinary evaporation. However, when water is heated to its boiling temperature, it can begin to evaporate not only from its surface, but also from within. If a steam bubble forms inside the hot water, water molecules can evaporate into that steam bubble and make it grow larger and larger. The high temperature is necessary because the pressure inside the bubble depends on the temperature. At low temperature, the bubble pressure is too low and the surrounding atmospheric pressure smashes it. That’s why boiling only occurs at or above water’s boiling temperature. Since pressure is involved, boiling temperature depends on air pressure. At high altitude, boiling occurs at lower temperature than at sea level.

But pay attention to the phrase “If a steam bubble forms” in the previous paragraph. That’s easier said than done. Forming the initial steam bubble into which water molecules can evaporate is a process known as “nucleation.” It requires a good number of water molecules to spontaneously and simultaneously break apart from one another to form a gas. That’s an extraordinarily rare event. Even in a cup of water many degrees above the boiling temperature, it might never happen. In reality, nucleation usually occurs at a defect in the cup or an impurity in the water—anything that can help those first few water molecules form the seed bubble. When you heat water on the stove, the hot spots at the bottom of the pot or defects in the pot bottom usually assist nucleation so that boiling occurs soon after the boiling temperature is reached. But when you heat pure water in a smooth cup using a microwave oven, there may be nothing present to help nucleation occur. The water can heat right past its boiling temperature without boiling. The water then superheats—its temperature rising above its boiling temperature. When you shake the cup or sprinkle something like sugar or salt into it, you initiate nucleation and the water then boils violently.

Fortunately, serious microwave superheating accidents are fairly unusual. However, they occur regularly and some of the worst victims require hospital treatment. I have heard of extreme cases in which people received serious eye injuries and third degree burns that required skin grafts and plastic surgery.

You can minimize the chance of this sort of problem by not overcooking water or any other liquid in the microwave oven, by waiting about 1 minute per cup for that liquid to cool before removing it from the microwave if there is any possibility that you have superheated it, and by being cautious when you first introduce utensils, powders, teabags, or otherwise disturb very hot liquid that has been cooked in a microwave oven. Keep the water away from your face and body until you’re sure it’s safe and don’t ever hover over the top of the container. Finally, it’s better to have the liquid boil violently while it’s inside the microwave oven than when it’s outside on your counter and can splatter all over you. Once you’re pretty certain that the water is no longer superheated, you can ensure that it’s safe by deliberately nucleating boiling before removing the cup from the microwave. Inserting a metal spoon or almost any food into the water should trigger boiling in superheated water. A pinch of sugar will do the trick, something I’ve often noticed when I heat tea in the microwave. However, don’t mess around with large quantities of superheated water. If you have more than 1 cup of potentially superheated water, don’t try to nucleate boiling until you’ve waited quite a while for it to cool down. I’ve been scalded by the stuff several times even when I was prepared for an explosion. It’s really dangerous.

For a reader’s story about a burn he received from superheated water in a microwave, touch here.

What is the device called in some watches that transforms the kinetic energy cre…

What is the device called in some watches that transforms the kinetic energy created by the watch’s motion into energy to help power the watch’s battery? And how does such a device work? — KW, Washington, DC

As a number of readers have informed me, the watches you’re referring to generate electricity that then powers a conventional electronic watch. These electromechanical watches use mechanical work done by wrist motions on small weights inside the watches to generate electricity. Seiko’s watch spins a tiny generator—a coil of wire moves relative to a magnetic field and electric charges are pushed through the coil as a result. I have been told that other watches exist that use piezoelectricity—the electricity that flows when certain mechanical objects are deformed or strained—to generate their electricity. In any case, your wrist motion is providing the energy that becomes electric power.

These electromechanical watches are the modern descendants of the automatic mechanical watches. An automatic watch had a main spring that was wound by the motion of the wearer’s hand. A small mass inside the watch swung back and forth on the end of a lever. Because of its inertia, this mass resisted changes in velocity and it moved relative to the watch body whenever the watch accelerated. If you like, you can picture the mass as a ball that rolls about inside a wagon as you roll the wagon around an obstacle course. When the lever turned back and forth relative to the watch body, the watch was able to extract energy from it. Gears attached to the lever allowed the watch to use the mass’s energy to wind its mainspring. The energy extracted from the mass with each swing was very small, but it was enough to keep the mainspring fully wound. Ultimately, this energy came from your hand—you did work on the watch in shaking it about and some of this energy eventually wound up in the mainspring.

These same sorts of motions are what power the electromechanical watches of today. Instead of winding a spring, your wrist motions swing weights about inside the watches and these moving weights spin generators to produce electric power.

I recently read a full-page ad for FREE ELECTRICITY from a company called United…

I recently read a full-page ad for FREE ELECTRICITY from a company called United Services Company of America. Their Website is at http://UCSofA.com/Free%20Electricity.htm. I walked through their site and viewed some of their videos “demonstrating” clear violations of the well-known and well-founded Laws of Thermodynamics, and listened to the description of the new Fourth Law of Motion (following Newton’s other well known three). Are these people the same who were denied patent approval for a Perpetual Motion Machine? Have any reputable independent test labs reviewed their products under controlled conditions? Do they publish, even at a price, the fundamental mathematical and physical processes that allow for the claims that seem to be shown? I realize you’re not a “debunker”, but maybe you can shed some light on this. They have scheduled dozens of seminars across the country at considerable cost (and most likely considerable profit to them), and taken out full-page ads in national newspapers. The speakers do not comment on their academic training or experience, but tend to speak of hidden conspiracies from the power industry to stop their proliferation of free power. — DH

What a great find! This site is filled with pseudo-science at its best. I don’t know the history or training of these people, but it’s pure garbage. They use the words of science but without any meaningful content. Just as putting on a crown doesn’t make you a king, using phrases like “action and reaction” and “Newton’s third law” doesn’t mean that you are discussing real science.

I watched the video on the “Counter Rotation Device” and found the discussion of “Newton’s Fourth Law of Motion” quite amusing. The speaker claims that this fourth law was discovered about 30 years ago by a person now at their research lab. It is based on Newton’s third law, which the speaker simplifies to “for every action there is an equal and opposite reaction.” In a nutshell, his fourth law claims that you can take the reaction caused by a particular action and apply it to the action in the same direction—action causes reaction which causes more action which causes more reaction and so on. Pretty soon you have so much action and reaction that anything becomes possible. The video goes on to show devices that yield more power than they consume and that can easily become net sources of energy—by using part of the output energy from one of these energy multiplying devices to power that device, you can create endless energy from nothing at all.

Sadly enough, it’s all just nonsense. Newton’s third law is not as flexible as the speaker supposes and this endless feedback process in which reaction is used as action to produce more reaction is ridiculous. A more accurate version of Newton’s third law is: “Whenever one object pushes on a second object, the second object pushes back on the first object equally hard but in the opposite direction”. Thus when you push on the handle of a water pump, that handle pushes back on you with an equal but oppositely directed force. The speaker’s claim is that there is a way to use the handle’s push on you as part of your push on the handle so that, with your help, the handle essentially pushes itself through action and reaction. You can then pump water almost without effort. Sorry, this is just nonsense. It’s mostly just playing with the words action and reaction in their common language form: if you scare me, I react by jumping. That action and reaction has nothing to do with physics.

The speaker uses at least three clever techniques to make his claims more compelling and palatable. First, he refers frequently to a power-company conspiracy that is out to destroy his company and its products. Conspiracy theories are so popular these days that having a conspiracy against you makes you more believable. Second, he describes the fellow who discovered the fourth law of motion as a basement inventor who has taken on the rigid scientific establishment. Ordinary people love to see pompous, highly educated academics brought low by other ordinary people; it’s kind of a team spirit issue. And third, he makes casual use of technical looking equipment and jargon, as though he is completely at ease in the world of advanced technology. Movies have made it easier to trust characters like Doc Brown from “Back to the Future” than to trust real scientists.

In fact, there is no power-company conspiracy because there is no free electricity. The proof is in the pudding: if these guys really could make energy from nothing, they’d be doing it every day and making a fortune. They would be the power companies. If they were interested in public welfare rather than money, they’d have given their techniques away already. If they were interested in proving the scientific establishment wrong, they’d have accepted challenges by scientific organization and demonstrated their devices in controlled situations (where they can’t cheat). The fact is, they’re just frauds and of no more interest to the power companies than snake oil salespeople are to doctors. No decent people want to see others defrauded of money, property, or health, but the free electricity people present no real threat to the power companies.

The popular notion that an ordinary person is likely to upset established science is an unfortunate product of the anti-intellectual climate of our present world. Becoming a competent scientist is generally hard work and requires dedication, time, and an enormous amount of serious thinking. Physics is hard, even for most physicists. The laws governing the universe are slowly being exposed but it has taken very smart, very hardworking people almost half a millennium to get to the current state of understanding. Each new step requires enormous effort and a detailed understanding of a good part of the physics that is already known. Still, there is a common myth that some clever and lucky individual with essentially no training or knowledge of what has been discovered before will make some monumental breakthrough. The movies are filled with such events. Unfortunately, it won’t happen. In new or immature fields or subfields, it is possible for an essentially untrained or self-trained genius to jump in and discover something important. Galileo and Newton probably fit this category in physics and Galois and Ramanujan probably fit it in mathematics. But most of physics is now so mature that broad new discoveries are rare, and accessible only to those with extremely good understandings of what is already known. A basement tinkerer hasn’t got a prayer.

Finally, real scientists don’t always walk around in white lab coats looking serious, ridiculing the less educated, and trying to figure out how to trick the government into funding yet another silly, fraudulent, or unethical research project. In fact, most scientists wear practical clothes, have considerable humor, enjoy speaking with ordinary folk about their science, and conduct that science because they love and believe in it rather than as a means to some diabolic end. These scientists use the words of science in their conversations because it is the appropriate language for their work and there is meaning in each word and each sentence. The gibberish spoken by “scientists” in movies is often offensive to scientists in the same way that immigrant groups find it offensive when people mock their native languages.

I don’t know about any patent history for the free electricity organization but everyone should be aware that not all patented items actually do what they’re supposed to. In principle, the U.S. Patent Office only awards a patent when it determines that a concept has not been patented previously, is not already known, is not obvious, and is useful. The utility requirement should eliminate items that don’t actually work. One of my readers, a patent attorney, reports that he regularly invokes the utility regulation while escorting the “inventors” of impossible devices such as “free electricity” to the door. They consider him part of the conspiracy against them, but he is doing us all a service by keeping foolishness out of the patent system. However, proving that something doesn’t work often takes time and money, so sometimes nonfunctional items get patented. Thus a patent isn’t always a guarantee of efficacy. Patented nonsense is exactly that: nonsense.

Finally, how do I know that Free Electricity is really not possible? Couldn’t I have missed something somewhere in the details? No. The impossibility of this scheme is rooted in the very groundwork of physics; at the deepest level where there is no possibility of mistake. For the counter rotation device to generate 15 kilowatts of electricity out of nothing, it would have to be a net source of energy—the device would be creating energy from nothing. That process would violate the conservation of energy, whereby energy cannot be created or destroyed but can only be transferred from one object to another or converted from one form to another. Recognizing that our universe is relativistic (it obeys the laws of special relativity), the actual conserved quantity is mass/energy, but the concept is the same: you can’t make mass/energy from nothing.

The origin of this conservation law lies in a mathematical theorem noted first by C. G. J. Jacobi and fully developed by Emmy Noether, that each symmetry in the laws of physics gives rise to a conserved quantity. The fact that a translation in space—shifting yourself from one place to another—does not change the laws of physics gives rise to a conserved quantity: momentum. The fact that a rotation—changing the direction in which you are facing—does not change the laws of physics gives rise to another conserved quantity: angular momentum. And the fact that waiting a few minutes—changing the time at which you are—does not change the laws of physics gives rise to a third conserved quantity: energy. The conservation of energy is thus intimately connected with the fact that the laws of physics are the same today as they were yesterday and as they will be tomorrow.

Scientists have been looking for over a century for any changes in the laws of physics with translations and rotations in space and with movement through time, and have never found any evidence for such changes. Thus momentum, angular momentum, and energy are strictly conserved in our universe. For the counter rotation device to create energy from nothing, all of physics would have to be thrown in the trashcan. The upset would be almost as severe as discovering that 1+1 = 3. Furthermore, a universe in which physics was time-dependent and energy was not conserved would be a dangerous place. Free electricity devices would become the weapons of the future—bombs and missiles that released energy from nothing. Moreover, as the free electricity devices produced energy from nothing, the mass/energy of the earth would increase and thus its gravitational field would also increase. Eventually, the gravity would become strong enough to cause gravitational collapse and the earth would become a black hole. Fortunately, this is all just science fiction because free electricity isn’t real.

For more information about the “free electricity” hoax, sent in by readers of this site, touch here.

About 18 months ago, I saw an episode on “Current Affairs,” in Australia, in w…

About 18 months ago, I saw an episode on “Current Affairs,” in Australia, in which this dude made a “free electricity” machine, using magnets, fixed and non fixed-on a spinning wheel. While I know that I should be skeptical, I can’t help thinking “what if?” Have scientists carefully tested this stuff to see for sure that it does or does work? – P, Australia

Not surprisingly, no “free electricity” machines are ever released to real scientists for testing. That’s because the results of such testing are certain: those machines simply can’t work for very fundamental and incontrovertible reasons.

Like so many “scientific” conmen, the purveyors of this particular scam claim to be victims of a hostile scientific establishment, which refuses to accept their brilliant discoveries. They typically attack the deepest and most central tenets of science and claim that a conspiracy is perpetuating belief on those tenets. Their refusal to submit their work to scientific peer review is supposedly based on a fear that such review will be biased and subjective, controlled by the conspiracy.

The sad reality is that the “scientific establishment” is more than willing to examine the claims, but those claims won’t survive the process of inspection. In some cases, the authors of the claims are truly self-deluded and are guilty only of pride and ignorance. But in other cases, the authors are real conmen who are out to make a buck at public expense. They should be run out of town on a rail. >

Click here for more information about the “free electricity” hoax, sent in by readers of this site.