You must have a lot to say about diving with us, right? Such as the preparation before diving, the equipment, and even the sequelae caused by it.

Today, let's talk about the four most popular diving and related knowledge.

1.Scuba Diving

Scuba, an acronym for "Self-Contained Underwater Breathing Apparatus",was coined by Christian J. Lambertsen in a patent submitted in 1952.

The definition of scuba diving is fairly easy: a tank of breathable air strapped to your back to breathe underwater without the help of the surface you scuba dive. But with the tank removed, things got a little harder to pin down.

Diving depth: the maximum depth limit is 40 meters (130 feet)

About dressing: Most scuba divers will wear wetsuits because they help maintain body temperature and help protect the body against the sun and other hazards on the open sea. Even when the air temperature and surface temperature of the water are warm, it can get quite cold the deeper you dive. So wetsuits are standard attire.

Who are Suitable:Generally speaking, anyone in good average health and at least 10 years old can participate. Those people who have Lung problems, ear issues, allergies, and certain diseases are all potentially dangerous underwater.

Difficulty: 1 star

Safety: 4star

Recommended places:  Barracuda Point, Sipadan Island, Malaysia; Blue Corner Wall, Palau, Micronesia

2. Freediving

The newest and fastest growing of these tankless activities is free diving. Many people tend to refer to both snorkeling and skin diving as "freediving", but this is incorrect.

Strictly speaking, freediving is a competitively-oriented activity that requires more discipline than skin diving and snorkeling. Using the technique of taking in as much air as possible and using as little oxygen as possible underwater, freedivers try to spend as much time as possible on one breath to reach the maximum distance.

Diving depth: For most swimmers, a depth of 20 feet (6.09 metres) is the most they will free dive. Experienced divers can safely dive to a depth of 40 feet (12.19 metres) when exploring underwater reefs.

About dressing: Freedivers usually need to wear an exposure suit to protect themselves against the elements. This usually means a wetsuit as the primary focus is normally keeping the diver warm. However, in very warm water, freedivers often wear neutrally buoyant suits to protect them from the sun, jellyfish, or other hazards.

Who are suitable: The minimum age is 15 years old for the PADI Freediver course and 12 years old for the PADI Basic Freediver certification.

Difficulty: 3 star

Safety: 4 star

Recommended places: Oil rigs in the Gulf of Mexico ; Christ of the Abyss statue；Italian Riviera, Portofino

Cost: Getting your diving certification will cost around $400–$1200, while a set of scuba diving gear will be anywhere between $700–$2000.

3. Snorkeling

Snorkeling is arguably the most popular activity of the bunch. Probably because of all the named activities, snorkeling is the most accessible and least daunting. Hundreds of thousands of snorkelers take to the water every year on holidays or in their home waters, floating along on the surface

Snorkeling is defined as an activity where the participants use full-foot snorkel fins, masks,snorkels and possibly a buoyancy vest to help them remain afloat without strain. The defining point here is the tendency to stay at the surface, observing the aquatic environment below. The full face snorkel mask also provides a new riff on this old song, giving comfort and ease for some who have difficulty with a traditional snorkel.

Snorkelers can and will swim below to depth but not as much as skin divers.

Diving depth: up to 6 ft

About dressing: There are 10 gears you need to take for snorkeling, such as mask, snorke, fins, snorkel vest, fin socks or snorkeling booties, wetsuit ,swimsuit, boardshorts.

Who are suitable：basic swimming skills to stay afloat, move through the water and keep going for a while, easy enough for children

Difficulty: 1 star

Safety: 5 stars

Recommended places:  Ambergris Caye, Belize; Ilha Grande, Brazil; The Big Island, Hawaii

Cost: $200~$360( snorkel gear usually only costs 5-10% of what scuba gear costs)

4.Skin Diving

Skin diving is as old as swimming. It’s an old term that isn’t necessarily used much anymore but is useful nonetheless. Back before masks or goggles allowed for better vision underwater, divers were holding their breath and submerging to hunt flashy fish or find shiny treasure.

Essentially, skin diving is snorkeling, except you dive below the surface when there’s something interesting you want to see up close. Who hasn’t been swimming with a mask and tried to dive down to investigate some crab or coral garden? But anybody who has done this know from experience the sudden pressure that clenches the nasal passages and causes discomfort in the head. 

As soon the body passes more than a couple of feet deep, hydrostatic pressure begins to constrict the air and organs within. With every 33 feet (10 meters) of depth, the pressure squeezes any object by 14.5 psi. Any skin diver will then have learned well how to equalize, a skill used in freediving and by scuba divers.

Skin divers use snorkels at the surface and common diving equipment in terms of mask and fins are used.

Diving depth: No Limits Freediving (NLT)

About dressing: Skin divers wear masks, snorkels and sometimes wetsuits, depending on water temperature.

Who are Suitable：at least 12 years old

Difficulty: 1 star

Recommended places: the same as scuba diving

Diving is one of the most popular water sport in coastal countries, especially Europe and the United State.

But diving still carries some risk, which hopefully doesn't scare you. These risks include decompression sickness (DCS, "curved"), arterial air embolism, and, of course, drowning. Diving also has effects, such as nitrogen anesthesia, which can cause these problems.

Before diving, you must ensure that you have certain swimming skills, and at the same time ensure that your physical fitness is strong enough to dive.