Interesting facts about the underwater environment

Did you know that objects underwater, including their colours, do not appear the same as on the surface or that sound travels faster through water than through air? Have you ever wondered why scuba divers wear exposure suits, e.g. wet suits or dry suits?

The underwater environment offers unique experiences to divers, but at the same time presents them with a number of surprising challenges. Below are just a few examples.

Light & Colours

Objects underwater appear 33% larger and 25% closer than they actually are. So next time you see a big fish or look at your buddy underwater, remember that appearances can be deceiving.

In addition, as we descend deeper, colours start changing and eventually disappear. In clear water, red colour fades away at a depth of approximately 3-4 metres, orange – 9 metres, yellow – 18 metres, green – 27-46 metres, blue – 46 metres, and indigo and violet at 46+ metres.

As we go deeper everything appears to be gray-blue and shadows are less prominent or disappear altogether. This is one of the reasons why scuba divers take torches with them – by aiming the torch at fish, rock formations or corals, they can see their true colours.

Sound

Sound travels 4 times faster underwater and over a greater distance than on the surface.

The denser the water, the faster the sound travels. This means that in denser salt water, such as in our seas and oceans, sounds travels a bit faster than in fresh water (fresh water lakes, rivers, etc.).

Our ears are used to the speed of sound on the surface and our brain can easily determine the direction it is coming from. This is not the case underwater. A boat passing hundreds of metres away may sound as if it is right on top of the diver.

Heat

Underwater our bodies give away heat 25 times faster than on the surface. Heat loss is a big challenge for any scuba diver. This is the main reason scuba divers wear exposure suits.

Water conducts heat better than air. Water can also evaporate from various objects, including the diver’s skin and protective suit. In addition, heat can be transferred through the movement of fluids, meaning that an ill-fitting wet suit may cause warm water trapped inside the suit to rise, freeing up space for cold water and thus accelerating heat loss.

Finally, all objects radiate heat. The warmer the object, the more heat it will radiate. A scuba diver’s body is usually warmer than the surrounding water and this results in heat loss.

DAN Diver Insurance Plan

DAN divers alert networkEnsure your safety by joining the best diving insurance plan on the marketLearn More

Latest News

  • Neutral Buoyancy

    Neutral buoyancy – what, why and how

    Mar 3

    A scuba diver’s ability to establish and maintain neutral buoyancy throughout the dive and with any equipment configura…

  • Balloons Underwater

    Your lungs: scuba diving vs free diving

    Oct 18

    Do you know what happens to your lungs when you take a breath and dive in with your mask and snorkel or what happens to…

  • decompression theory

    Decompression theory?

    Oct 2

    One of the most common things that aspiring scuba divers as well as people that are simply interested in the sport are w…

  • i had a dream

    I had a dream…

    Sep 5

    Since I was a little kid I’ve been dreaming of being able to live and breathe underwater. Water, anything and everything…

  • Try Scuba

    Why try scuba diving?

    Aug 30

    We were compelled to write this short article because many people ask us: Is scuba diving really for me? What does it ta…