Introduction
Many people have difficulty in understanding the Catt Question. This is understandable given the inconsistency and confusion that is produced by the current definition of electricity. (Here is the original formulation of the question.) It will probably come as a surprise to the reader that there is no clear and precise definition of electricity. Consequently, despite the fact that one of the first requirements of any science is to have a clear and precise definition of the concepts involved, the concept of electricity has no consistent meaning in physical science and consequently it means different things to different people. Since to have a meaningful scientific discourse, it is imperative that words mean the same thing or refer to the same concept, this presents a difficult problem that needs to be resolved. In the case of the word electricity we have a problem, and that difficulty arises when we try to understand the Catt Question and what it is specifically asking.
The specific difficulty arises from the fact that the concept of electricity refers to two completely different conceptual ideas in physics. The first idea is that electricity refers to a property of fundamental particles called charge. The second idea is that electricity refers to energy in the form of electromagnetic fields. In order to understand the Catt Question, it is imperative that the reader understand that the question requires that the answer choose between the two different definitions of electricity in giving an answer. That is the answer to the question needs to define electricity as being either fundamental particles called electrons, or as being energy in the form of an electromagnetic field. The importance of the Catt Question reveals itself in the way the answers are given. That is what definition of electricity the answer uses. Some answers choose the definition that electricity is the fundamental charged particles known as electrons and attempts to answer the question in terms of that definition of electricity. The second type of answer tries to answer in terms that the definition of electricity is energy in the form of electric and magnetic fields which are somehow created by the electrons. It is clear from the failure of both types of answer to the Catt Question that the answers that are provided from both of the definitions are not completely adequate, or in more specific terms the answers are not correct physics. This leaves us with the following difficulty, which the Catt Question is actually aimed at solving. It requires us to rethink the established concepts of physics as applied to electricity and magnetism and to develop new ones that more properly reflect the nature of the physical world.
Definition Of Electricity
Here is the initial definition of electricity as given by Merriam-Webster on the internet:”a form of energy that is carried through wires and is used to operate machines, lights, etc.” However, this is the “full definition” that appears later: “a : a fundamental form of energy observable in positive and negative forms that occurs naturally (as in lightning) or is produced (as in a generator) and that is expressed in terms of the movement and interaction of electrons b : electric current or power.” It may not be obvious to the reader that these two definitions contradict each other. It is not entirely obvious that the first definition is the correct one and that the second definition is faulty and leads into the conundrums and problems that arise in The Catt Question. Before going on, lets discuss what is wrong with the definition in a. The definition says that electricity is a form of energy observable in “positive and negative forms”. Energy doesn’t appear in this manner and so since there is no such thing as positive or negative energy, the definition must be referring to something that is not energy. Clearly it refers to what is called positive or negative charge. But these are not forms of energy, and so the definition is misleading us. The definition goes on to tell us that these positive and negative forms of energy are “expressed in terms of movement and interaction of electrons.” This is where the definition leads us into trouble that specifically generates the Catt Question. Because we are told that it is the electrons that are involved in the “expression” of the energy that is defined as electricity.
The basic thesis of Ivor Catt goes to his experimental observations regarding cross-talk on transmission lines, where he observed that his experiments demonstrated that “opposite electric currents flowed through each other.” This presents a problem if we think of the electric current as defined in a and b according to Merriam-Webster. That is because this definition implies very strongly, but incorrectly, that an electric current is a flow of electrons and it is quite obvious that it is physically impossible for two physical flows of electrons to exist at the same time in opposite directions. However, if we define electricity in accordance with the first or initial definition as given above, the problem of two physical currents flowing in opposite directions is eliminated.
It has been many, many, years since Ivor Catt realized that this was a serious difficulty in the theory of electricity and magnetism, and tried to eliminate it by banishing the traditional concepts of electric charge and current found in physics textbooks. The Catt Question is the result of these attempts to get physics to correctly define electricity in terms that does not lead to an obvious contradiction with the experimental facts. This shows us something very significant about science. That is that once a physical idea or concept has become accepted as scientific fact, it is difficult and almost impossible to correct the error even though it is obvious that the experimental evidence shows that it is false. In other words, ideology trumps experimental facts in science, despite the illusion presented by scientists that science is firmly established on the facts or observations derived from the objective experimental evidence.
The Catt Anomaly
In 1996 Ivor published a book titled “The Catt Anomaly”. This has been used by his opponents to interpret the Catt Question as being an anomaly or paradox. It is neither of these, because as Ivor says, it is merely a question. The anomaly that Ivor Catt is referring to in his book is not the anomalous behavior of electric current or charge but to the anomalous behavior of scientists with respect to answering the Catt Question. The ironic truth is that the Catt Anomaly is not really about the Catt Question, which Catt’s opponents think it is, but it is about the way the scientific world responded to the problems posed by the issues raised in the Catt Question. That is the Catt Anomaly refers to the behavior of the scientific community when faced with the demand that the Catt Question be answered. That demand seemed required since there were no answers to the Catt Question that were offered. The response to the problem of the definition of electricity was the scientific community ignored the problem. So Ivor Catt set out to resolve that by insisting that an answer was needed and ought to be provided. His book describes his adventures in getting answers to the Catt Question and tells us more about resistance to change in the scientific community than it does about the nature of electricity.
Formulation Of Catt Question
As discussed before, the Catt Question has its origin in the problem that if electric currents can flow in opposite directions at the same time, then these currents can not consist of the movement or flow of physical electrons as is taught in physics textbooks. This was not, and is not new, since electrical engineers who worked with power transmission and radio had known about this for years. That is that electromagnetic waves can move in opposite directions on transmission lines and there is no problem or difficulty with that. The problem did not and does not arise in electrical engineering, because they use the initial definition of electricity given above that it is energy in the form of electric and magnetic fields. The idea that electricity is energy in motion therefore poses no problems unless that movement is attributed to the physical process of electron current flow. Electrons have mass and so therefore can not have a velocity approaching the velocity of light. To be precise, this problem does not normally arise in engineering or physics, because of the way different models are used in different applications. The electron flow idea is used in applications of electronics at low frequencies and in applications involving circuit theory. In applications involving radio frequency the primary ideas or models used involve electromagnetic fields. Using these different models does not involve contradictions or inconsistencies, because they are based upon different assumptions regarding the nature of electricity. It is only when we try to develop a model that encompasses a complete and logically consistent theory of electricity that problems and difficulties arise.
One of them is the problem of currents flowing in opposite directions at the same time. Radio engineers see no problem here because they doesn’t use the definition of current as being a physical movement of electrons, for them it is a flow of electromagnetic power in the form of electromagnetic fields. However, a physicist trained to think in terms of current as a physical phenomenon caused by the flows of electrons inside a wire, the idea of two opposite currents flowing in different directions at the same time is a severe contradiction. This contradiction not only involving a collision of physical particles, but a contradiction involving how it is physically possible to induce a flow in two different directions at the same time.
As stated above, the engineering world was perfectly comfortable using the different definitions of electricity based upon the differing assumptions and definitions about the nature of electricity. This brings us to the problem of designing digital circuits. Traditionally, these circuits were designed using the methods of DC circuit analysis. Ivor Catt was a digital design engineer and his problem was to design high speed digital circuits. It turns out that this problem required that design engineers adopt a different definition of electricity than is normally used to design DC digital circuits. These circuits use signals sent as pulses or electrical states that represent ones and zeroes inside a computer. The problem was that these signals in the form of ones and zeroes do not follow the laws of DC circuit theory modeling. They travel at the speed of light and so a different definition of electricity was needed than had been previously used. The problem is simply this, if electricity is the movement of electrons in wires then it is impossible for them to travel at the speed of light inside wires, and so there was a problem in the physics being used, because that physics says that electricity is the movement of electrons as stated in the definition a. given above.
The formulation of the Catt Question has to do with the question of how is it possible for the charge in DC circuits to move at the speed of light, since it is obvious that this is impossible. The fact that it is impossible for electricity, as defined in terms of the movement of electrons, to travel at the speed of light, is however, not very evident to the scientific community. Nor is it very easy to formulate the problem in a way that makes it clear exactly what the difficulty is.
The History Of Electric Current
A look back at history helps to understand the issue behind the Catt Question. The main issue is what exactly is electric current and why do textbooks tell us it is a flow of electrons in wires? The answer to this question should be clear and obvious, but unfortunately it isn’t, and a look at the historical record gives us hints as to the difficulties involved. The historical record tells us that the concept of electricity is not as well established as it seems in physics textbooks.
Traditionally the concept of electric current, or current, referred to the movement of electricity. But what electricity was was totally unknown. The modern belief is that electric current is the movement of electricity, that is of a charged particle called the electron, and that this produces a magnetic field. This idea begins with the discovery, or perhaps more properly the invention, of current electricity by Allesandro Volta. He produced current electricity by his invention of the chemical battery. But this electricity was not the same kind of electricity as had been known previously. That form of electricity was produced by mechanical friction. The really important discovery, again perhaps we should use the word invention, was by Oersted who showed that the electric current, in those days known as Galvanism, produced by a chemical battery also produced a magnetic field. Here we are using the word current to describe the phenomenon, but it is a purely modern word based up the assumption that electricity actually consists of charged particles.
Oersted thought that his experiment, where he connected the poles of a battery via a metal wire demonstrated what he called the “electric conflict”. His idea was that the magnetic effect was produced by the conflict of the two electricities, plus and minus that emerged from the poles of the chemical battery. Other scientists had different opinions on the matter. Biot for example insisted that the wire became magnetic an idea originated by J.J. Prechtl. This idea was natural considering that wires in those days were made from iron. The attribution of the magnetic effect to the flow or current of electricity was pretty well established when Maxwell published his treatise on Electricity and Magnetism in 1873. But there was nothing in it which attributed the magnetic field to a flow of electrons as in our current conception of it. That idea appears to have come about as a result of the rise of the atomic theory and the integration of the theory of electricity and magnetism into the ideas about the structure of matter that resulted from the atomic and nuclear theories developed in the early years of the 20th century.
The background to the atomic theory has its roots in the search for the structure of matter. That is the question, what is matter composed of? Today the atomic theory answers that question in terms that it is the charged elementary particles the electrons and protons that are the fundamental building blocks of atoms. Hence since it is believed that atoms consist of negatively charged electrons orbiting a positively charged nucleus, then it is natural to assume that it is the electrons that account for the current of electricity that is observed in experiments. Unfortunately, this assumption is contradicted by a rather impressive body of evidence that contradicts it.
That body of evidence has its roots in the theory of electricity and magnetism attributed to James Clerk Maxwell. Maxwell is celebrated for his discovery of electromagnetic waves, but the truth is that his theory is only the first step to that important concept. The much more important discoveries for our story were made by Oliver Heaviside. Heaviside developed the theory that electromagnetic waves traveled on wires and this theory he used to develop a theory of wire transmission for telegraph communication. These discoveries combined with the discovery of radio waves by Hertz marked the high-point of the Maxwellian theory of electromagnetic waves. But these discoveries were overshadowed by the discovery of the electron by J.J. Thomson. Soon the emphasis of physical study shifted to a what is called the electron theory and this change in emphasis resulted in a complete disavowal of the Maxwellian idea that electricity traveled as waves on wires.
Cullwick’s Justification Of Electron Conduction Current
In his book Fundamentals of Electromagnetism, 1939, page 42, E.G. Cullwick discusses why the modern definition of current replaced the older conception of Maxwell. Basically Cullwick says that the older definition of current based upon the electromagnetic system of units was defective, because it was not “fundamental.” He says, “At the present day, however, the definition is not logically consistent with our knowledge, for it leads to the definition of quantity or charge of electricity as something which moves when current flows…we are led through the magnetic field and electric current, to electric charge as the most hypothetical concept, whereas we now regard it (through our acceptance of the fundamental nature of the electron) as a basic reality…The trend of modern physics, since the discovery of the electron has been to substantiate the fundamental nature of electric charge, and to make more and more hypothetical the field concepts of Faraday and Maxwell.”
At the time this was written in the 1930s, the discovery of the electron had produced the marvelously useful results of vacuum tube electronics, and many other inventions such as radio and television that were based upon the movement of electrons through a vacuum to control a current of electricity. This constitutes the primary evidence for the fundamental idea that the electron is electric current. However, there were disturbing contrary facts that were beginning to appear in practical applications. For instance, the electron tubes were unable to amplify high frequency electron currents to produce amplification, although these currents flowed in the wires without any high frequency obstruction. The development of the microwave electron tube ought to have been the final blow to the electron theory of current but by the time of the development of the traveling wave tube or TWT, the theory was pretty well entrenched.
The design of the traveling wave tube or TWT was based upon a fundamental fact that the electron current in the tube vacuum, did not have sufficient velocity to match the velocity of electricity in normal electric wires. To bring the two velocities into consonance, the velocity of the electricity, viewed as a traveling wave, had to be reduced to the velocity of the electric current in the tube vacuum. In other words, although the electrons were accelerated to very high speeds in the tube, using extremely high voltages, the velocity attainable was many times slower than the velocity of electricity in plain metallic wires. Hence it is clear that the velocity of electricity in wires is close to the speed of light while the velocity attainable by electrons in free space is extremely slow in comparison.
Time Domain Reflectometry (TDR)
Time domain reflectometry is a technique for finding faults or breaks in transmission lines carrying power or communication services. It is based upon the fundamental principle that electricity moves at close to or near the velocity of light and that the circuit does not have to be closed for the electricity to flow. Both of these principles contradict the electron current flow definition. The technology uses a DC pulse generator to send fast rise time narrow pulses into a coax cable or more precisely a transmission line. An oscilloscope is used to detect the time the pulse is transmitted and the return time delay of a reflection. The location of the fault in the transmission line is determined by calculating the distance from the pulse generator using the velocity of the pulse on the transmission line which is known to be on the order of the speed of light. Hence it is experimentally known that the velocity of electricity is that approaching the speed of light. In addition, the utility of the technique is that it can identify where the line is broken and so the break can be found and repaired. However, the modern definition of current is inconsistent with this because it is necessary for the circuit to be closed before any electron current can flow because it is required that a electric field be established within the completely closed circuit before current can flow.
One of the key issues involved in the Catt Question involves just exactly how the pulse produced by a TRD travels down the transmission line as a current. In particular, since the circuit is not assumed to be completely closed, it is asked in the question, how does the charge appear on the lower wire. In this particular case, the charge can not be induced into motion by an electric field if there is no closed circuit for the electric field to be created or induced inside the wires of the transmission line or coax cable. Hence the question is a serious one for the electron current model of electricity. That is because we know from experience that even though the cable or line may be completely severed into disconnected parts, that the pulse will be sent down the line, and when it is reflected from the severed point, the distance to the break will be known from the time of the arrival of the reflected pulse. This fact alone refutes the electron theory of current in wires.
Final Comments
The Catt Question has a specific origin in the inconsistency regarding the definition of electricity and hence the conception of electric current that has been discussed here. The question began as a result of an exchange of letters that appeared in Wireless World in August 1981. (For page 1 and page 2) In this exchange Catt took specific issue with the concept of electron current in wires as a response to an electric field induced within the wires of the closed circuit that induced the resulting electron conduction current flow. In the Catt Question, Catt asked specifically what is the source of the charge in the bottom wire. This would be current induced by the electric field that was produced as a result of the closed circuit connection. However, Ivor Catt argued in favor of the Maxwellian view, that was developed and advanced by Heaviside, that the flow of electricity is due to waves on the wire and not the conduction of electron current. Hence in the Catt Question, it is asked how is it possible for charge appearing as a result of electron conduction current to appear in the bottom wire if the wave from the energy source is advancing at the speed of light. This question certainly does not have an answer within the electron conduction current paradigm, since we know that while the velocity of electricity is the speed of light, it is clearly impossible for electrons to travel this fast as a result of an electric field produced in a closed electric circuit.
About the Author
