The Science of Diving

Good day, fellow wanderers! As of some time around 10 pm last night I am one step closer to achieving Dive Master status. I finished up the Science of Diving component. Whoo! What does this mean?


It means I practiced dive tables over and over and over. I’m so happy for dive computers.

The Science of Diving course covers some of the nitty gritty stuff of diving. We started with the physics of diving, going over gas laws; the effects of temperature, pressure, density, and other physical laws, and gas laws.

Next was some pretty cool material covering the physical effects of diving on your body. For instance, when you are under water, your abdomen is compressed and the diaphragm is displaced upwards, limiting the amount your lungs can expand. Blood flow is affected, shifting around from the limbs to the thorax. The text goes over a lot of physiology and potential injuries, including how to handle particular situations such as squeezes and DCS.

Decompression theory. This part included some interesting tidbits about the evolution of scuba diving. We went from almost exclusively super macho Navy divers with no buoyancy compensator (all leg power!) in the 1950’s to the modern recreational diver donning  the customized color-coordinated dive system. This led into the “total diving system” describing all the components needed for safe and happy scuba diving. Of course here I felt a little guilty for not owning all my own gear yet. I’m getting there.

Finally, my favorite, the underwater environment. This is the part I’m really excited to focus on. Becoming more familiar with tides and currents, navigation, underwater terrain, and topography. We went over some various types of aquatic life and the potential dangers involved with sticking your hand in a hole you can’t see in or stepping on the bottom, like you know you aren’t supposed to. The lesson learned in this chapter is LEAVE EVERYTHING ALONE! Take only pictures. Leave only bubbles. And don’t get lost.

Cool! So next is the Dive Guide component, which means I’ll be working on leading dive trips. Damn the bad luck. But really, what the heck is a Dive Guide?

Some background: PADI and SSI are two internationally recognized SCUBA certifying organizations. Both of them are available to you to learn to dive and to continue learning beyond the basics.

Enhancing your dive training is recommended for any SCUBA diver. The level you choose to achieve depends on what you want out of your diving; is it just for fun or do you want to go pro? Do you want to learn how to dive in caves or at altitude? Do you want to learn how to dive a wreck?

These are questions to consider but will likely change over time. (At present, I am on the SSI Dive Master course. This is the first step to becoming a diving “professional”.)

I began my training with PADI. I completed my Open Water DiverAdvanced OW Diver, and Rescue Diver through Seal Sports, a dive shop in Louisiana. I also began my Master Scuba Diver training before moving to Florida – it’s still a work in progress, and one I’m now realizing has less merit than I first presumed.

I became fixated on racking up dives and completing the necessary Specialty Courses to achieve the PADI MSD rating. And then one day I asked someone, how can I actually use this rating?

Basically, you can’t. The MSD rating is not a professional one. I’ve heard Master Scuba Divers referred to as an “elite” group. It sounds fancy but I am learning it is achieved by so few because it is geared toward the hobbyist, while the Dive Master rating is like an apprentice. Realistically, it’s likely that fewer people are willing to pay for a rating that (more or less) says you’re a diverse leisure diver.

Master Scuba Diver is not a total wash, though. The nature of the MSD program ensures you have dive experience, as you must have a minimum of 50 logged dives; and that you are a well rounded diver, as you must complete several Specialty Diver certifications. You must also be an Advanced OW Diver and a (Stress and) Rescue Diver. 

Master Scuba Diver is the highest rating amongst recreational divers, but I dare say it is probably only a good investment if you’re looking to improve certain skills, or want to sound fancy to your non-diving friends. Who are those people. Hipsters.

Dive Master, on the other hand, is your first step to becoming a Dive Professional. PADI and SSI handle training in slightly different ways, but they can both prepare you for Dive Master rating.

Dive Master requires similar prerequisites to MSD, except now there are more fees and insurances to pay. SSI breaks down the Dive Master program into two components:

  • The Science of Diving
  • Dive Guide


The Science of Diving covers in depth knowledge about what happens to your body when you are underwater, the causes of, effects of, and responses to situations that can occur while diving; the diving environment, and diving equipment.

Dive Guide can lead and guide certified divers. A Guide cannot certify you to scuba dive; however, upon compdive-science02leting the Snorkeling Instructor Program a Guide can certify you to snorkel. I had no idea you could be snorkel certified.

Other training programs follow the Dive Master rating, but I won’t touch on those much until I begin them myself. Personally, I’ve completed Rescue Diver and two specialities (Peak Performance Buoyancy and Enriched Air). I’ve begun UW Photography and Gas Blender, and I have almost 40 logged dives, inching closer to the Dive Master Rating.



I’ve have had experience with both PADI and SSI. They are both internationally recognized, meaning you can be SCUBA certified through either organization and be able to get your tanks filled worldwide. There are subtle differences, however. I switched to SSI largely because they are more popular here in the Tampa Bay Area. To put it short, PADI likes to market and assert its control over the programs a bit more than does SSI, and PADI is better at selling “stuff”.

PADI is an acronym for “Put Another Dollar In”. Just kidding. It’s for the Professional Association of Dive Instructors. SSI stands for SCUBA Schools International.

Another (nominal) difference is the naming of the courses and titles. They are pretty much interchangeable, though, so if you are cave certified through PADI but dive with a shop who trains SSI, you’re golden. In fact several dive shops train through multiple programs. It’s also pretty easy to switch between the two if you begin with one and continue training with another, as I have.


What specialities have you taken? Which dive agency have you trained under?



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8 thoughts on “The Science of Diving

  1. South East Asia and Australia so far. Hoping to do Vanuatu and then the Philippines at the turn of the year. I just got back from a couple of dives on Ningaloo Reef near Exmouth. Great soft coral, reef sharks and turtles on display as we as the reef regulars in good size and number


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