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Understanding Electricity by Using a Water Tank Analogy

Every time an electrologist turns on their epilator, they prepare to manipulate electrical current. The constant flow of electrical current running from the power outlet into their epilation machine can be adjusted in many ways, and it is the judgment of the electrologist that determines which machine settings will best serve their clients. Understanding both how electricity functions and how changes to epilator settings impacts the electrons flowing to electrolysis needle probes, will provide electrologists with an additional tool to achieve excellence in their work. 

Voltage, Current, and Resistance

Electricity is defined as the movement of electrons. This movement is what makes the electrical tools and appliances work in our homes and out in the world. We measure how electrons move in three fundamental ways

Voltage: difference in electrical charge between two locations or the potential energy available , labeled V and measured in volts

Current: rate of flow of electrons, labeled I and measured in amperes or amps

Resistance: a materials tendency to slow down electrons movement, labeled R, and measured in ohms

If this all makes sense and you now fully understand how electricity works, excellent. You're done here, no need to read anymore. For the rest of us, let's consider water movement to help us understand this concept better.

Water as Analogy for Electricity

The way that electricity moves and is measured can be compared to the flow of water from a water tank into a hose attached to the bottom. If we look at this water flow system, we can describe it with a few common factors.

Image illustrates water flowing through a tank to a hose.

The tank volume (how much water is in the tank) determines the water pressure (the downward push of the water). The hose width limits how much water can come out of tank and, along with the water pressure, affects the water current (how much water moves the hose) and the output volume (how much water comes out of the hose per minute). If the water refills the tank at the same rate as water comes out the bottom, then the water volume in the tank, and therefore the water pressure in the tank, never changes.

Scenario 1: Water Volume Drop

Let's imagine a scenario where the water fill is turned off such that as water leaves the hose, the tank volume goes down. There are no changes to the tank size or hose width.

Water level drops leading to reduced water output volume (aka water pressure).

In this case, as water exits the hose, the tank volume will go down and the water pressure will drop. Even though the hose diameter remains the same, over time the water current will drop and less water will flow through the hose (the water output volume).

Scenario 2: Water Hose Diameter Reduced

A second scenario is if the size of the hose is reduced without changing any other parameter.

Thinner diameter water hose results in lower water pressure.

Since the tank has the same amount of water in both cases, the water pressure stays the same. But as the hose narrows, less water can go through it under the same pressure. This results in less water coming out of the hose, thus dropping the water output volume.

Scenario 3: Adjusting water flow to accommodate smaller tank

What if we now use both adjustments to create the same water output volume? We can reduce the water volume by using a small tank and at the same time increase the hose volume. If done carefully, this should allow us to get back to the same water output volume as in our original setup.

Reducing tank size while simultaneously widening hose diameter results in similar water pressure.

These different scenarios show how the various parts of the water tank can affect the output volume. Now lets apply these concepts to the flow of electricity.

Moving to Electricity from Water Tanks

We can take the descriptions of how water moves through a hose from a tank to explain how charge moves through a battery. Instead of water in a tank, we have a volume of charges in a container such as a battery. The amount of charge is described in units of Coulombs (C). The pressure this charge exerts on the tank is the Voltage, described in Volts (V). The flow of charge through the hose is called the Current and is described in Amperes, or Amps for short (A). Finally, the hose width correlates with the resistance of an electrical wire, which determines how much charge can flow through, and is described in Ohms (Ω).

Water Tank Compared to Electrical Charge ‘Tank’, i.e. a Battery.

Similar to a tank running out of water (think of your toilet bowl not flushing properly when the tank doesn't refill), a battery uses up its electrical charge when the charge pressure, or voltage, drops. This eventually reduces the charge output to a level where not enough current is reaching its target. Imagine a flashlight that eventually dims and then goes out as the battery runs out of power.

V = I x R (V = voltage in volts, I = current in amps, R = resistance in ohms). This formula is referred to as Ohms Law and is fundamental to calculating voltage and current for electrical systems.

citation: every physics book ever

By contrast, for a piece of electrical equipment connected to a power outlet, the 'battery' never runs out of power. Therefore, the voltage doesn't change, and only the current and resistance can be adjusted. This is the case for most epilation machines. The knobs you turn or buttons you push on your machine change the amount of current going through the electrolysis probe by raising or lowering resistance and current.

When doing electrolysis don't forget that your electrolysis probe is part of the 'wires' of your epilator such that switching to a thinner wire results in an increase in the resistance in the system. If you switch to a thinner needle with the same voltage setting on your epilator or electrosurgical machine, a higher current will delivered to the tip of the needle.

-S Paisner, President of Synoptic Products

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