So that you can see the animals and plants in the bottom of the water. When you try to open your eyes in the water, you can see only one pieceA blurry scene, because water is denser than air, and light refracts when it reaches the water. The focal length of the eye is adjusted according to the light in the air, so the lens keeps the cavity in front of your eyes and gives you a clear view. Mask and swimming glasses big difference is that the former not only cover the eyes also cover the nose, this is because when diving in order to prevent extrusion, the need to balance the pressure inside the nasal cavity, so swimming glasses cannot be used for diving. The general lens consists of a reinforced safety glass lens, a rubber or silicone band that fits the face, and an adjustable headband with a fixed position. Reinforced safety glass lenses can prevent the glass from breaking into thin, highly dangerous pieces. The edges are made of silica gel, which is stronger than rubber, because silicone lasts 3-4 times longer than rubber, making skin less sensitive, softer and more comfortable. Some mirrors have a drain valve, a one-way valve to drain water from the mirrors. Two important things about choosing a mirror are fit and comfort, and so are other equipment. An inappropriate mirror may leak and may cause allergies, reducing the pleasure of diving. To test the fitness of the mirror, simply place it gently on your face (no need to wear a headband) and inhale through your nose. The right mirror will cling to your face until you exhale. Also, make sure you can easily hold your nose out of the mirror. There are many types of face glasses, including single lens, two lenses and many lenses. Usually only two lenses are equipped with corrective lenses.

When your water is resting or floating, and your face is looking down or looking for something, you can breathe through your breathing tubeSuction. Second, when there are wind waves on the water surface, you can use the height of the nozzle of the breathing tube is usually higher than the height of the wave to avoid water flooding into the mouth. When snorkeling, the breathing tube is a necessary equipment, you can do it without lifting your head out of the water for a whole day. The general design of the breathing tube is to open one end of the mouth, the other end is a bite of the elbow. The upper part of the breathing tube (tube body) is usually a semi-rigid plastic tube, and the lower part of the bite is mostly made of silica gel. A proper breathing tube should be properly curved (to fit your own face shape) with an inner diameter of about 2 cm and a length of 30 to 35 cm. A proper breathing tube is easy to breathe in addition to comfort. Try, you can put the mouth pieces in between lips and teeth, will play on the left ear, mouth pieces should be comfortable, appropriate will not scratch the mouth or cause fatigue, chin and is straight in his mouth.

The practice of face mirror drainage must first assume that the face mirror is filled with water to avoid the potential danger of water choking. In addition, cramps caused by improper use of frog shoes may also cause drownings. Therefore, a professional coach should be employed to guide the skill practice, so as to minimize the accident rate in the activity. As for snorkeling techniques, they can be divided into:

Although I chose a set of face mirrors suitable for my face shape, there are always some external factors to make the lens water when diving on the surface of the water. If the water cannot be discharged or continues to enter the water, the following questions must be noted:

1. Whether the wearing position of the face mirror is correct.

2. Whether there is hair or foreign body between the mirror and face in the middle.

3. Whether the nose exhales gently, slowly and persistently.

The probability of water entering the breathing tube is very high. As long as the Angle of wearing is wrong or there are waves, the breathing tube will enter the water. In addition, when floating from the bottom to the surface of the water, the breathing tube water. Then you can use the drainage technique to remove water from the breathing tube and continue breathing.

There are two ways to drain a breathing tube:

A jet is a short, strong exhalation of air in the lungs from the mouth. Since most of the breathing tubes are now designed with a drain valve, there is no need to exert too much force on the exhalation channel.

2. This way of drainage of gas expansion type is for no drain valve of the breathing tube after diving picks up the design skill, in the floating process of the underwater vomit first some air in the pipe, and looked up at the surface suppression, the breathing tube after reaches the surface water, such as nature is outside the expansion of the air squeeze tube.

There is a great difference between activities in water and those on land, especially in water where there is great resistance and it is quite difficult to move. Therefore, a lot of oxygen is needed. So proper respiratory control is also a way to reduce the production and accumulation of carbon dioxide.

There are two ways to control breathing:

1. The diaphragmatic breathing refers to the surface when each breath breathe in deeper than usual, because breathe in deep, of course, the slower of snorkeling movement patterns will also slow down the speed of the breathing, but can increase the exchange capacity of the gas and relatively lower residual gas ratio.

Rapid breathing is a type of breathing used when swimming rapidly on the surface of the water. This breathing can be adjusted to match the speed of the shoe kick and is self-determined, but rapid movement and breathing do not last long and may lead to hypoxia over long distances or periods of time.

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