So you are starting to learn about electricity. As a graphic example of ohms law we will use two bodies of water connected by a pipe.

We have been told and know that V=IR, but why does it work? This is a simple explanation of Ohm's law and why it works.

First, Let's start with the terms:

V=voltage

The easiest way to think of voltage is to call it potential. Infact, lots of people refer to voltage a potential. Voltage is the potential to do work. Imagine two bodies of water connected with a pipe. If one body of water is higher than the other then there is potential for water to flow from the high potential to the low potential.

I=current

Current is simply the transfer of something from one place to another. In the example with two bodies of water connected with a pipe, the current is the actual flow of water through the pipe between the two bodies of water.

R=resistance

Resistance is the, well, resistance. It is anything that opposes the flow of current. In the example of two bodies of water connected by a pipe, resistance is formed by the pipe. As the pipe gets wider, more current flows because the resistance gets lower. As the pipe gets narrower, less current flows because the resistance gets lower. If there were no pipe between the two bodies of water, then we woud say there is infinite resistance. No current would flow.

So now lets put it all together, and create ohm's law. Let's try to solve for I (current) based on what we know about voltage (potential) and resistance.

First we will start with voltage. If we think back to the example of two bodies of water connected with a pipe. If we move the higher body of water even higher, then we create more potential between the two bodies of water. If nothing about the pipe between them changes, then the water will flow faster. Therefore, if V goes up, I goes up.

Now we look at resistance. If we constrict the pipe by making it less wide then we get less water flow. We have increased the resistance of the pipe. Thus, if R goes up, I goes down.

Now we can put it all together:

I=V/R

This equation covers all of our requirements for the relationships between voltage, current, and resistance. If we rearrange the equation we get:

V=I*R