Background
Electricity is defined as the presence of charge, which is better thought of as the flow of particles with charge (e.g. electrons flowing through a wire). The energy of these particles in motion can be converted to other forms of energy, such as creating light in a lamp, playing sound from a stereo, or lifting people in an elevator. To understand electricity, the atom is revisited. With sufficient energy, a force causes an electron to leave an atom.
When this force (called a voltage) occurs across many atoms, multiple electrons will create a flow, called a current. Electrons may move between atoms, forcing the next electron to leave the atom, continuing the process of electron flow.
In the process, electrons may bump into atoms, which is called resistance. This causes a vibration of the atom, which is measured as temperature (heat). The relationship between voltage (V), current (I) and resistance (R) was established by Georg Ohm in 1827 and became known as Ohm’s Law. It is simple V=IR. An additional equation is used to determine the power (P) from electricity, which is simply P=VI.
The force that causes electron motion is the electromagnetic force. Although the electric force of particles can be calculated with Coulomb’s Law, the law is not capable of explaining how electrical energy can be converted to other forms of energy. For example, how can the force of multiple electrons (with charge) be converted to move an object (with mass)? Since charge and mass are different units, there is no current way to model or explain how electricity can be converted to other forms… yet we know that it can.
Explanation
Electricity is Electron Motion
All motion is the movement of particles. Whether it is the motion of electrons in a conductor (electricity), the motion of a car, or the rotation of Earth, all of these can be traced back to particles. So, when the laws of physics are applied to a single electron in motion, and then the sum is taken for the total contribution of all electrons, we can see how electricity can be used and converted to any type of energy.
A New Definition of Electrical Measurements
To explain and understand how electricity can be converted into other forms of energy, we need to understand how it is measured. A single electron is never measured, but instead, it is a collection electrons. The properties of electricity can be rewritten now knowing the principles of EWT, specifically that particle charge is constructive and destructive waves, measured as an amplitude (in other words, Coulombs are replaced with meters as the SI units). Refer to the fundamental physical constants which were rewritten when charge (C) is distance (m).
- Voltage – A measurement of force between two points
- Current – A measurement of average electron velocity
- Resistance – A measurement of mass flowing in a given timeframe
The New Electrical Units
The simple change from charge to distance in units allows electrical equations to be related to non-electrical equations. The new, standard SI units are found below and compared to the units for mechanics.
The Relation of Ohm’s law to Newton’s 2nd Law
Now, we can understand how electricity can be converted to move an object with mass (m). Let’s start first with an example using Newton’s 2nd law and how it can be used to calculate a force (F=ma) and the velocity (v=at) of two falling objects of 1 kg mass each, on Earth (acceleration is rounded to 10 m/s2 for simplicity). The one on the left drops for 2 seconds. The one on the right is stopped by an object after 1 second.
In the example above, the following is calculated using Newton’s laws:
- Force – 10 newtons (kg*m/s2)
- Velocity of ball on the left – 20 m/s
- Velocity of ball on the right – 10 m/s
- Average velocity of balls – 15 m/s
Now, let’s compare this to two electrons in a wire with a voltage of 10 V. For simple math, let’s assume the electron weighs 1 kg (it’s easier math than making the balls in the above example weight 9×10-31 kg, which is the electron mass).
Given a force, electrons will move. Some electrons may collide with an atom and stop. Similar to the example used above with balls, the electron on the left travels for 2 seconds without collision. The electron on the right collides with an atom after 1 second. Regardless of a collision, resistance is measured as the mass traveling in a given timeframe.
In the example above, the following is calculated using new EWT definitions and Ohm’s law:
- Resistance of electron on left – 1/2 kg/s (1 kg of mass travels in 2 s)
- Resistance of electron right – 1/1 kg/s (1 kg of mass travels in 1 s)
- Total resistance of electrons – 2/3 kg/s (ohms – see equation below)
- Velocity of electron on left – 20 m/s (I=V/R where V=10; R=1/2)
- Velocity of electron on right – 10 m/s (I=V/R where V=10; R=1/1)
- Average velocity of electrons – 15 m/s (amperes – see equation below)
They are identical! The velocities of each ball/electron and their averages are exactly the same.
When particles are thought of in classical terms, and charge is replaced with wave amplitude, Ohm’s Law is the same as Newton’s 2nd Law. Think this was just a trick with these numbers? Try adding more electrons, or different properties from the example and it will always match Newton’s laws. Physics does indeed operate under one set of laws for objects from the smallest size to the largest in size.
But… We Can’t Measure Individual Electrons!
Electricity is the motion of many, many electrons. While the example above illustrates how the laws of physics can be unified, we can’t measure electrons individually. What we are actually measuring is the average velocity of electrons (current) and the total mass of electrons traveling in the total timeframe (resistance). It is a collection of electrons.
The total resistance is the sum of all mass divided by the sum of all all time. The total resistance equation, using the example numbers above, would be a resistance of 2/3 ohms (kg/s).
Current is the average velocity of all electrons. The average velocity equation, using the example numbers above, would be a current of 15 amps (m/s).
Thus, we measure the collection of electrons in this wire and calculate voltage according to Ohm’s law, with a current of 15 amps and 2/3 ohms, to arrive at 10 volts.
Power – Now it Makes Sense!
When we modify the units of charge, we can understand how power is transferred from electricity to mechanical systems (or other systems). The motion of electrons contains energy which is then transferred to the motion of other particles (atoms). Power is energy over a given timeframe.
One way to think about power is the ability to accelerate a mass a given distance (energy) in a given time. For example, electrical power can be used to lift a 15 kg kid against the force of gravity (a=10 m/s2) a distance of 1 meter in one second, as illustrated below. This requires a power of 150 watts.
This fundamentals of converting electrical power to mechanical power has been understood for many years, otherwise we wouldn’t have working escalators or elevators. But understanding and modeling the conversion with equations was impossible because of the difference in units. Now, the relationship between Ohm’s law and Newton’s 2nd law allows the equations to be merged in values and units. Using the numbers from the examples above, the conversion of power is shown to be equal (including units). Mechanical power (Pm) and electrical power (Pe) both agree with a calculated 150 watts.
One Set of Laws
Electricity is the motion of charged particles, like the electron. Newton’s laws of motion apply to objects, made of particles. When the classical laws of physics are applied to particles, and then the summation is taken for the total particles in an object, we find that everything can be expressed from the motion of a single particle. One set of laws!
Video – What is Electricity?
The What is Electricity video provides an explanation of the electric forces, how electrons flow and the relation to classical mechanics.