A Weighty Matter

The average person probably does not think about the weight of water. That average person is not like you and hold that coveted scuba diving certification. Have that understanding that water plays a critical role in what happens to our body while diving. Sure, we learned that a cubic foot of freshwater weighs 62.4 pounds. That same cubic foot, when turned into salt water now weighs 64 pounds. Simple answer for the differences is that salt water contains salt and other minerals. That is why you are so much more buoyant in salt water than fresh water. You can always check out the previous blog on Archimedes Principles. Now, talking about the weight of water. When you start scuba diving, you are actually going to get thinner. Reason is that the pressure of water is pressing against every portion of your body. I will use sea water for the following demonstrations. So when you drop off that boat in the sunny Caribbean water, at 30 feet you are already going to have an additional 13.32 psi pressing against you. You remember from your Open Water Scuba Certification we have 14.7 psi pressing on our bodies on the surface. Easy way to calculate this is to multiply 0.444 by every foot you are underwater. We get 0.444 by dividing the weight of the water by 144. You can do the same with fresh water and you should get 0.433. So if we dive to 120 feet in sea water we know that we will have 53.28 psi in water pressure against us. Total pressure against us would be 67.98 psi. There, the mystic of how to do that is removed. So next time you are watching that show on deep diving and they start throwing numbers out there, you can prove them correct or incorrect. You would be life of the party and gain the admiration of fellow divers. So see, you can handle pressure…..

Comments (0)

No comments yet.

Leave a comment