The Carotid-Sinus Receptors are part of a complex chain of nerves regulating arterial pressure and if the range they regulate exceeds a predetermined limit they signal for a reduction of that pressure by slowing the heart down.

The best thing to do with these kinds of questions is to establish a baseline for any additional calculations by taking the object up to the surface. This makes the surface the constant to use for the rest of the question.

If it's taken up through 25m/sw it will expand 3.5 times (25m/sw=3.5ATA). This will make the object 70% of its total volume (3.5x20=70).

We then take the object down to 10m/sw which is 2 ATA (70/2=35)


Learn more about physics in diving on one of my upcoming PADI Divemaster or PADI Instructor Development Courses

Hope you've got your sea legs for this one!

The stern of the boat is the rear. The bow is the front. Port is left and Starboard is the right when facing forwards.

Learn more about boat diving techniques on our comprehensive PADI Divemaster program. 

The revised Advanced Open Water Course includes Adventure Dive options from Rebreather, Ice, Self-Reliant and Cavern Specialty Courses which have a minimum prerequisite age of 18 years old.

This can be checked in the Instructor Manual - Advanced Open Water and there is a pretty easy to reference chart showing all pertinent details about Adventure Dives available for the program.

Want to learn more about my upcoming PADI professional diver development programs? Message me at This email address is being protected from spambots. You need JavaScript enabled to view it. and we'll arrange a time to chat.

The recycling of the breathing gas while scrubbing carbon dioxide and supplementing oxygen into the system is undoubtedly the present and future of diving. Read more about these units in your PADI Encyclopedia of Recreational Diving.

CCR is on my 'to-do' list for sure.