Name: Scuba Diving for Beginners - Understanding Atmospheres Underwater is Easy
Uploaded: 2025-05-13T05:45:52.000Z
Duration: 3 min 2 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

Understanding Atmospheres Underwater is Easy.

When you breathe in, your lungs inflate, and when you breathe out, your lungs deflate.

So, what would happen if you held your breath while scuba diving?

If you held your breath while descending, your lungs will become smaller, creating dense pressure inside your full lungs.

If you held your breath as you ascended, the air in your lungs would increase in size under pressure.

In either scenario, eventually your lungs would fail.

This is why the number one rule of scuba diving is never hold your breath.

So, you might be thinking, why does pressure change underwater?

It's simple, the deeper you dive, the higher atmosphere you're in.

When diving into a higher atmosphere, the volume of air spaces will get smaller, and the molecules in those spaces will become more compact.

The term atmosphere is simply a unit to measure ambient pressure.

Since water is denser than air, greater changes in ambient pressure occur underwater.

Every 33 feet of depth adds another atmosphere to the ambient pressure.

Once you understand atmospheres, you can calculate your own air consumption at a given pressure.

Helping you plan your dives efficiently and accurately.

As a recreational scuba diver, you are trained to dive safely between one and five atmospheres.

At sea level, you start your dive at one, and as you descend deeper underwater, the pressure and density increases, and the volume decreases.

This relationship between Pressure, Density and Volume stays consistent.

At 33 feet deep, you're at two atmospheres.

At this depth, volume is one half of what it was on the surface, and the density is two times denser.

This relationship continues as you dive deeper.

All the way down to 132 feet, we're at five atmospheres, the volume is 1/5 of what it was on the surface, and the density is five times denser.

Think about it this way, if you had a balloon at the surface with a volume of 10 units.

Taking it down to five atmospheres would reduce the balloon's volume to two units.

Because at 132 feet, the volume of an object is 1/5 of what it was on the surface.

Learn how to dive with Chris Brock, a PADI instructor teaching introductory dives, private scuba lessons, advanced certifications, and guided underwater tours in Maui, Hawaii.

Join the Ohana and follow Chris on social media and visit chrisbrockscuba.com for videos, articles and lessons on learning how to dive.