Put aside your intuition, eyeballs , and physics book and lets look at the actual choices most of us have for moving in everyday life:
- You can move forward/backward
- You can move left/right
- You can move anywhere between the above two
Model: just an x-y plane
The user base at Steemit is highly intelligent (despite me being part of it), so I know the exceptions are rattling off in your heads. It is not a perfect model, and I will address a few of the exceptions, but I think it fits well for about %80 percent of daily activity. If your offended that I would planarize your motion so unjustly, please keep reading, and if your still not convinced at least there are some cool photos at the end.
You might be thinking, well elevators go up/down and that is what you are missing in your points, so that should add another degree of freedom. Let's be real, here are your choices in an elevator
- No choices, just stand and try not to fart or get caught staring at people
Model: a point
Walking Up Everyday Stairs
I would consider stairs a place where you actually lose a degree of freedom. My model for stairs would be
- You can move up/down the stairs
Model: a number line
I get that you can step side to side on a staircase, and yes I have moved a sofa through a staircase before where that little bit of side wiggle room saves you from getting crushed, but for everyday life this isn't much of a choice.
Walking Up a Hill
A hill seems to be the next progression from stairs. There certainly is an elevation gain and a lot of lateral room to move to. The model for a hill:
- You can move up/down the hill
- You can move left/right on the hill
- You can move anywhere between the above two
Model: x-y plane again
It is much the same as walking on flat land, the difference is its slow going up and fast going down. You can dig into the hill and ruin my fun, but for those who have never dug a hole...its a lot of work and should count for -1 dimensions.
- you can jump forward/backward
- you can jump left/right
- you can jump to anywhere in between the above two
- you can temporarily reach a certain height while jumping
Model: 3-D but limited to certain paths
You've got me here, but this is kind of fake three dimensional motion. Point three only references full freedom in two dimensions. Once you jump you can't change your path (you can't just hang air at the top and shuffle ten feet to the right).
This is where you actually have full three dimensional freedom.
- you can swim forward/backward
- you can swim left/right
- you can swim/sink/float up or down
- You can move anywhere between the above three (limited by pressure and available air)
Model: Full three degrees of freedom at safe/achievable depths
I'm sure most people have swam before and know what a pleasure it can be, but you can only actively swim for a few seconds underwater before having to resurface. Scuba solves that problem by strapping a tank of air on your back! This gives you a good 30-40 minutes of exploring what's beneath the water and enjoying the experience of being weightless and (finally) fully free to move in all three directions.
Wouldn't you just sink? Nope, you should be equipped with a Buoyancy Control Device (BCD), which is like a life jacket where you can control how much air goes into it. The BCD allows you to achieve what is called Neutral Buoyancy. This is a state where you neither sink nor float up, you are suspended peacefully in the water.
Photo of me in neutral buoyancy, no swimming required, just suspended and feeling cool.
At this point you can swim in any old direction and explore; however, there is one way to change directions without actually having to swim. Breath!
By breathing in deeply and holding your breath, you increase your buoyancy and start to float up. This can be especially useful if you are cruising near the bottom and taking a close look at the fish/coral but there is a rock or some other object in your path. Since you are so low, using your fins to swim up might damage the coral, so the best option is to take a deep breath in and slowly float up while you keep swimming forward. You'll swim past the obstacle and breath out to go back to neutral.
Some photos from my first dives ever. They were in the Great Barrier Reef. It was probably one of the best experiences of my life.
The sites are beautiful, but even without the strange new underwater world you get to explore, I think scuba is just an enjoyable experience. That additional degree of freedom in motion can be confusing, challenging, and exhilarating. It certainly isn't a cheap or easy activity, but there are a lot of places at common tourist locations that will help you through it. Please keep in mind that you need to be supervised and trained in order to scuba dive, so please be smart and safe. Just try it instead of getting boozed up on the beach (nothing wrong with that, but it can get dull), you won't regret it.