T³: Adventures in Science – What is Voltage?

Over the next few weeks, we'll explore the basics behind electricity in a series of videos.

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As we begin focusing some of our efforts on the classroom, I wanted to offer some free content that is easily usable by teachers and digestible by students. In that same vein, I wanted to make it short and sweet so it can be injected into a class or consumed by the curious mind.

Over the next few weeks, I'll be releasing a series of videos that cover the basics of electricity and electronics. I hope that they act as a tie-in to introductory circuits lessons found in many physics classes. I realize that many of you who frequent this blog already have a solid grasp of the basics, so I am looking for feedback from those of you who already know this stuff: What worked? What could have been explained better? What would you have done differently when describing how electricity works?

Why a concept video? It turns out that some of the most popular pages on our site are the introductory electronics tutorials that cover topics like What is Electricity? and Ohm's Law. As I worked my way through the written guides, I wanted to turn them into 5--10 minute video summaries. The first video, "What is Voltage?", found most of its inspiration from Jimb0's "What is Electricity?" guide:

What is Electricity?

June 13, 2013

We can see electricity in action on our computers, lighting our houses, as lightning strikes in thunderstorms, but what is it? This is not an easy question, but this tutorial will shed some light on it!

Comments 7 comments

  • Laser printing is a really cool example of using static electricity.

    Cathodic protection on pipelines is another cool use of electricity for environmental protection.

  • I've been working with electronics for roughly a half century, starting with doing things with batteries and flashlight bulbs as a kid, working for a bit over a year as a factory tech, working as a broadcast engineer at a TV station, finally getting my engineering degree in 1980, and then working as a software and electronics engineer. Seems to me that there's a good chance I might know something about the subject...

    Anyway, I started with, and have frequently used, the similarities between electricity in a wire and water in a hose. Voltage corresponds to the pressure in the hose, and current corresponds to the flow of water (albeit with the caveat that electrons are "flowing backwards"). Although not entirely accurate, it is a VERY easy concept for the vast majority of people to visualize.

    Starting with strict definitions, and deriving concepts, MIGHT work for a FEW people, but does NOT give the good, intuitive feel that leads to making exciting new developments.

    From the title, and build up as being for educators, I certainly expected something a lot less technical than this apparent "putting the cart before the horse [and substituting ropes for traces]" provided. At least change the title to "What is the Definition of Voltage?"

    By the way, in roughly 50 years of near-every-day using voltage, I'm hard pressed to think of more than a time or two when I needed the "joules per coulomb" definition of voltage -- and then only to get a couple of points on an exam in school. I really think that starting with the water-in-a-hose simile would make it FAR more friendly to the beginner.

    • I definitely appreciate the feedback. The water or air analogy is used most often for electrical concepts, and for good reason. I'm planning on introducing it in another episode to help discuss circuits, but I found that it didn't quite apply when talking about voltage as it relates to static electricity (since there weren't any wires to mimic hoses or tubes).

      I want to relate the intuitive to strict definitions, but if starting with the definition first seems a bit premature, I'll see about placing the demo or intuitive concept first to allow the viewers to get a "feel" for the subject. Many thanks!

      • I am afraid I may have come off a little more negative than I'd intended, Shawn. I really am supportive of SparkFun's efforts to support education. But the one thing that there's always room for is improvement!

        As for a way to talk about static electricity, the thought comes to mind of a tin can that has had too much pressure build up inside it and is about to explode. (We've all been told not to eat the contents of a can that's distended, as it may contain botulism!) Or, if you don't like that, maybe a balloon -- when the pressure exceeds the strength of the balloon, it explodes, and likewise, when the voltage on the cloud gets too high, it gets discharged with a bolt of lightening.

        One of the things I've always disliked about the water analogy is that it doesn't require a "closed circuit" -- chop the hose in half, and you get lots of water spraying around, but if you chop the wire going to the flashlight bulb in half, the bulb goes dark and that's about the end of it. (Yeah, there are weirdos that will claim otherwise, but we can pretty safely ignore them.) Anyway, keep trying!

  • This was an incredibly informative video and, as a fourth grade teacher, I am excited to have resources that deepen my own knowledge. However, there is the pressing issue of that lab coat. Where can we get one!?

  • Maybe contact this guy:




    For me the big thing is learning what not to explain of what I taught and shown, and having cosmology examples of the for things we see in electronics.

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