End result from the tutorial "Trap Your Friends in a Jar Using Photoshop."
When Galileo talked about dropping things off the Leaning Tower of Pisa, he wasn't actually proposing that anyone do it. Sure, it was an experiment, but just not the kind involving actual physical objects. Galileo's stone throwing was thought experiment—a mental exercise that explored a concept in a rational, methodical manner. The actual experiment, then, was the process of thinking through a question by applying certain theories or principles.
When I look at Photoshop tutorials, they generally do not interest me in the slightest. I don't want to turn people into zombies, create realistic 3D objects from scratch, or turn zoo creatures into fire-breathing, intergalactic, neo-grunge montages. So, I don't know why I decided to look at "Trap Your Friends in a Jar Using Photoshop" when I came across it on Pinterest. I mean, it's really not something I care to attempt in real life or in Photoshop. I thought the end result was pretty good, so I read through the entire tutorial out of curiosity, just to see how it was done. I had zero interest in doing it myself, but it reminded me that going through a tutorial as a "thought experiment" could be a learning experience in its own right
The jar lesson
Step one of the tutorial is taking the photographs, step 2 is extracting the photos of people, and step 3 is placing them in the jars. Step 4 is where it gets interesting. You've pasted photos of people onto photos of jars, but it hardly looks like they're actually in the jars at this point. This is where we see the signs of a good tutorial: instructions explain why we need to do the steps. A quote from step 4:
"Grab a small brush with low opacity, and gently brush away parts of their body which would -in reality- be obscured by the thick parts of the glass. This is the beginning of the illusion that they are in the glass."The subsequent steps explain, for example, how lightly tinting the subjects will help them look more like they are behind glass, how color overlays might help match the lighting conditions to the people to the jars, how adding highlights and shadows will create more realism, etc. For me, the explanation of the thought process turned this into a thought experiment.
The good and the bad
Many, many Photoshop tutorial books rely on this same philosophy. They have a series of lessons that teach you how to create posters, menus, or whatever with the hope that you will then be able transfer the knowledge to suit your own needs—pretty much the goal of all teaching. The good books (like Matt Kloskowski's Layers) help you make the connections between Photoshop tools and creative problem solving. The not-so-good books (and web tutorials) just say "do this...do this..now do this" and so on until "ta-dah! intergalactic grunge tiger!"
The dream and the good intentions
Of course, the dream tutorial is the one that works not only as "thought experiment," but also as something that solves a problem you actually needed to solve. This, by the way, is one of the reasons I haven't been writing as many tutorials myself (although I keep thinking I will)—I don't usually need to solve problems beyond portrait retouching (and I've given you my basic workflow), black and white conversions, and basic adjustments. My "real-life retouch" is meant to show you the thought process I go through when working on a particular photo. Hopefully, I'll make myself do some of those soon and they might serve as thought experiments for your own work. Meanwhile, I will just encourage you to think about what Photoshop (or just photo) problems you might want to solve and imagine how you could solve them.