Guitar Pickup Science Fair Project

[felix]

My son (currently in 6th grade) is doing a science fair project related to electric guitar pickups. For any of you who haven't helped a kid out with a science fair project lately, it's not just a DIY make-a-gadget sort of thing - you actually have to have a hypothesis, then gather data through experimentation, and end up with a conclusion.

 

So I'm thinking my son will need to choose a variable and keep the rest the same - so we can either change something about the magnets used in our homemade pickups, or we can change something about the wire used.

 

What I'm wondering (hopefully someone can help me out) is what will be the easiest way to the most obvious (and hopefully measurable) differences related to whatever we change? Ideally, the differences would be something that he can form a hypothesis about in advance based on readily available science info.

 

I was relieved to find some pretty cool pickup projects already posted on the web - so I think if I can guide him in the right direction, this could be pretty cool.

[Jeff da Weasel]

What about the winding of the pickups? It's been an item of much debate over the years. Check into it.

[Music Calgary]

Great project -- awesome idea.

[Phil O'Keefe]

He's going to want to read up on inductors and Faraday.

 

What variables can you put into a pickup design / build, and how will those affect the properties of the pickup? Wire gauge, magnet strength, number of wire coils / wraps / "turns" - how would varying any one of those elements change the response of the pickup? All other things being equal, will more wraps of wire give you more output, or less? What other side effects, if any, would come along with that? What if you keep the coils the same, but change the strength of the magnet?

 

Sound can be subjective in some ways, but certain aspects of the pickup can be measured, such as impedance and output. Change either the magnets, the wire diameter / gauge, or the number of wraps and you'll be able to measure the differences fairly easily with just a DMM.

 

Considering the large amount of turns of wire it takes to make a decent pickup, I would think that varying the magnet strength would be the easier item to test from a "build" standpoint.

 

Good luck with the project.

 

 

 

 

PS - Here's a link he may find helpful.

[MikeRivers]

 

My son (currently in 6th grade) is doing a science fair project related to electric guitar pickups. For any of you who haven't helped a kid out with a science fair project lately, it's not just a DIY make-a-gadget sort of thing - you actually have to have a hypothesis, then gather data through experimentation, and end up with a conclusion.

 

Ah, yes. I remember science fairs. They're starting early. I think my first opportunity to enter was 7th grade.

 

Does he want to actually build a pickup (or several) and show how differences in construction or materials affect the sound? That's likely to be a pretty hefty mechanical project.

 

How about if his project demonstrates and explains the effect of different loads on the pickup? He could either prove or debunk the effect of boutique cables, or easily demonstrate the effect of capacitive loading by comparing the sound of a pickup with a normal length cable, an outrageously long cable (maybe a 250 foot roll with connectors attached to each end) and a normal cable with a test box that puts different capacitors and resistors in parallel with the pickup.

 

This could provide a demonstration with actual audible effects if the differences were sufficiently gross, and the calculations supporting the audible effects are easy enough for a sixth grader.

[Lee Knight]

Wow. You guys have great ideas... but perhaps a little too subtle for the intended demographic? Why not use the above ideas but keep it very simple to illustrate them. For instance:

 

Two different pickups in one guitar (just ignore that one is in the bridge position and one in the neck, the distinction will be lost on them, or use 2 different guitars)

 

One low gain, one high gain, make the difference a big as possible in your pickup choice.

 

Explain why one is low and one is high gain. What principles come into play here. Physical and less tangible differences could be illustrated on poster boards.

 

Then set up a chain (little practice amp) that will will be driven to obvious distortion with the high gain pickup and sound weak an anemic with the low gain. Then switch between them playing Smoke On the Water.

 

Rock and Roll Classroom!

[Lee Knight]

As a matter of fact, the concept of GAIN itself might be lost on the audience.

 

So even a simple and clear illustration of 2 sine waves, one with a small amplitude and the other obviously BIGGER.

 

Then perhaps a picture of a garden hose next to a fireman's hose, both trying to put out the same fire out, or both trying to fill a swimming pool with the fireman the clear winner.

 

Then a depiction of the 2 different pickup types both driving the same little amp. All illustrating the difference in gain and where the variables occur.

[felix]

Great suggestions, Lee, but Phil is closer to the right track. Here's an example scenario:

 

1) my son comes up with a hypothesis like "a longer coil will create a stronger signal because ...... " (could be correct, could be incorrect)

 

2) we get a couple of identical magnets

 

3) we wrap one with less wire, and one with more

 

4) we set it up so a guitar string can vibrate over both of them

 

5) we see which one has more output

 

6) then we see whether the hypothesis is right

 

7) and then we set it up in a way that people can see what we did.

 

If we want to make it more complex, we could do 4 homemade "pickups" - and a couple could have the same length of coil, but different strength magnets.

 

Now I just need to figure out where to buy some materials. Fortunately, we don't really need to make a real pickup (though we could, I suppose).

 

Thanks so much for the input!

[UstadKhanAli]

I hadn't even thought of this in years. We had a Science Fair at my elementary school when I was in 6th Grade that few people attending would forget.

 

We were put in groups of four. The brainiac kid in my group simply asked for some simple materials, such as wire and a lantern battery and some other stuff that I can't remember, and simply said that he would take care of everything. He wouldn't tell us any more than this. We figured, "Well, he's really smart, we'll get a good grade, so sure...".

 

The day of the Science Fair, we showed up, still having no idea what he was going to do. And neither did the teachers. He had submitted something that was rather vague and evasive, but fitting their criteria. We show up at our booth, and he unveils his "experiment": he had somehow wired a dead frog to the lantern battery and when he joined two wires together, it hopped.

 

I don't remember exactly what happened after that, but we all got hauled into the principal's office with our teacher, although they quickly figured who was responsible for this "experiment".

[ermghoti II]

You'll want to get ahold of some sort of spectrum analysis software, to create concrete and objective results. You can buy Reaper for $50 or so, and d/l a shareware plugin.

[MikeRivers]

 

Great suggestions, Lee, but Phil is closer to the right track. Here's an example scenario: 1) my son comes up with a hypothesis like "a longer coil will create a stronger signal because ...... " (could be correct, could be incorrect) 2) we get a couple of identical magnets 3) we wrap one with less wire, and one with more 4) we set it up so a guitar string can vibrate over both of them

 

 

Warning! Science Fair Judge hat on:

 

It may seem interesting to apply a basic principle of electromagnetism to the practical application of guitar pickups but really all he's demonstrating is well known and predictable characteristics of a variable reluctance sensor. It's really better demonstrated with something more "physical" than a guitar string.

 

It would be more "scientific" to show how the various parameters are interrelated. Perhaps show the difference in output between a large diameter and a small diameter string at the same pitch vibrating over the same pickup, demonstrating that the larger diameter string creates the greater disturbance to the (fixed) magnetic field.

 

For a more interesting hypothesis, based on what he demonstrated with the above experiment, how it's possible that a pickup can have reasonably good balance between bass and treble strings. (you might be surprised at the answer)

[doug osborne]

Have him experiment with how a humbucking pickup gets rid of noise.

 

60 Hz, and possibly the change in other frequency response, should be easy to quantify.

[Martin Kantola]

One of the things that I would personally find interesting is how a neatly wound pickup sounds/measures compared to a messy one. But too subtle maybe for the project. Why not something radically different and crazy such as a pickup with small neodymium magnets and aluminum foil winding, results compared to a classic design?

 

Martin