Common sense of self-diving

1. What are the basic knowledge of diving?

Who is suitable for diving 1. You can swim easily 100 meter freestyle. I am not afraid of water, and I dare to open my eyes in the water. 3. Good health.

The following patients are not suitable for diving. 1. Drink up (drunk). 2. heart disease. 3. Sheep epilepsy. 4. Caught a cold. 5. nervous. 6. asthma. 7. Diabetes. 8. High (low) blood pressure. 9. About Otolaryngology.

The difference between snorkeling and scuba diving is 1. Snorkeling skin diving refers to the time that divers can hold their breath and dive in the water. Dive until you can no longer exhale and surface. 2. scuba diving refers to the way that divers carry air cylinders and breathe in the water for a long time through the air in the cylinders.

Absolute pressure 1. The pressure of divers. 2. Absolute pressure = atmospheric pressure+water pressure (one atmospheric pressure = 1 kg/cm2). Since we have adapted to atmospheric pressure since birth, we pay more attention to water pressure. 4. Gauge pressure = absolute pressure-atmospheric pressure. (Relationship between Gauge Pressure and Absolute Pressure)

The volume of gas in water is 1. At a certain temperature, the volume of gas is inversely proportional to the pressure ... Boyle's law. 2. The change of gas volume in water. 3. If we take the water depth as the interval of 10 meter, for divers. The maximum pressure change is within10m.

Buoyancy 1. When an object is put into water, a force equal to the weight of the water it discharges. This is called buoyancy. . .. Archimedes theorem. 2. Weight in water = weight in air-buoyancy (weight of discharged water).

Changes of vision and hearing in water 1. When light enters the water, it will be refracted. The object we see in the water looks bigger than the actual volume 1.25 times. 2. It will be closer visually. The sight distance will be shortened to 3/4 of the actual distance. Sound travels 4.2 times faster in water than in air. When the sound comes, it is almost heard by the left and right ears at the same time, so it is difficult to tell the direction of the sound.

The ear pressure balance is 1. Generally, divers will feel ear pain when they dive to a depth of three meters, which is the factor leading to the increase of water pressure. 2. The general ear pressure balance method is to pinch the nose from the top of the mask to block the nostrils, and then blow hard to let the air enter the ear canal. An experienced diver can even balance the ear pressure by swallowing water or swinging his chin left and right. 4. When balancing ear pressure, it is easier to keep your head up. 5. Every time you dive to a depth, you should immediately balance the ear pressure. Especially in shallow water, the times of ear pressure balance should be increased.

The answer comes from the extreme outdoor network official website.

2. Basic knowledge of diving

This is the precautions for diving in winter, mainly to keep warm.

Divers should wear dry diving suits, warm clothes and special warm gloves, and hot water suits can be used if conditions permit.

Secondly, we should pay attention to the maintenance of diving equipment. If the temperature is too low, the filter of medium-pressure air compressor with air source is easy to freeze.

If the water temperature is too low, the secondary pressure reducer is easy to freeze underwater. Maybe the secondary pressure reducer is frozen. At this time, we should open the bypass and get out as soon as possible.

If there are floating ice floes on the water surface, pay close attention to the movement of the ice floes when approaching the operation area and leave the water surface as soon as possible.

3. Basic knowledge of diving

Also, be sure to wear a headgear, otherwise brain numbness will affect underwater judgment and behavior. Thick gloves are necessary, otherwise it is difficult to press the respirator and perform other finger actions.

Take warm-keeping measures quickly after landing to restore body temperature.

4. What are the basic knowledge of diving?

Sudden diving situation and its solution

Cramp

If you are nervous, the water is too cold or you stay in the water for too long, you may get cramps. Prepare fully before launching, and don't stay in the water for too long. Once you get cramps, don't panic. For example, toe cramps, then immediately bend your legs and straighten your toes apart; For calf cramps, first take a deep breath, lie on your back on the water, hold your toes with your hands, and push your calf forward hard to stretch and relax the contracted muscles; When fingers cramp, make a fist, then open it hard, and release it repeatedly.

Dizziness and brain swelling

The main reasons are that the diving time is too long, blood accumulates in the lower limbs, cerebral ischemia, the body consumes a lot of energy and the body is overtired. Go ashore to rest immediately, keep warm all over, and drink some light sugar salt water properly.

Nausea and vomiting

That's what happens when you stick your nose in dirty water. Go ashore as soon as possible, and then press Zhongwan and Neiguan points with your fingers. If there is a Ren Dan, you can also include one. To prevent enteritis, you can also eat a few cloves of raw garlic.

The skin is itchy and has a rash.

It is mainly caused by skin allergy. Go ashore at once. Take chlorpheniramine or chlorpheniramine, and you'll be fine soon.

Itchy and painful eyes

It may be caused by unclean water. Wash your eyes with clean light salt water immediately after landing, and then use chloramphenicol or erythromycin eye drops, preferably a hot compress before going to bed.

have a headache

The reasons may be chronic rhinitis, choking or body cold, temporary cerebral vasospasm and insufficient blood supply. At this time, you should go ashore quickly, press Baihui point, temple point and Lieque point on your head with your thumb, then apply a hot towel to your head and drink a cup of hot water to get better.

Abdominal pain and bloating resistance

Abdominal pain and bloating will occur after eating or diving on an empty stomach. At this time, you should go ashore and lie on your back, press the atrium, the upper court or Zusanli with the tip of your thumb, and take 3 ~ 5ml of ten drops of water orally at the same time, and apply a hot towel to your abdomen.

Earache, tinnitus

It may be that there is water in the ear or water in the nose, and there are all kinds of drainage methods.

(1) Turn your head to the side where the ear enters the water, pull the earlobe hard, and jump with your ipsilateral leg.

(2) Aim the palm of your hand at the ear canal, tightly block the ear with your hand, tilt your head to the left when the left ear enters the water, and then quickly pull your hand away, so that the water will be sucked out.

③ Suck out the water in the ear canal with a sterile cotton swab.

Diving skills

1, get everything ready, please bring your bathing suit, towels, bath products, slippers, etc. When you get off the bus.

2. Listen to the explanation, and spend 3-5 minutes listening to a professional commentator to introduce diving activities. There are pictures of diving at the scene, as well as pictures of diving instructors.

3. Sign up, fill in the registration form, pay the money and get the diving ticket.

4. Change your swimsuit and take the ticket to the locker room to change your swimsuit. From the moment you get the diving ticket, the staff will arrange it for you and tell you what to do next.

Step 5 store clothes. Visitors who take part in diving can store their clothes for free. Slippers should also be stored at this time. Put on a diving suit barefoot. Please take care of your valuables.

6. Change the diving suit, which is specially designed. It can prevent the body from losing heat too quickly, so it has the function of heat preservation at the bottom of the sea. Even in winter, it won't feel cold in the water.

7. Shore training is the most important part. You must listen clearly and understand it. If you don't understand, ask the trainer quickly until you know everything. It will be very hot to put on a diving suit and train on the shore. At this time, you can open the upper body diving suit for air.

8. Don't be nervous when you get into the water. Remember what the shore trainer told you. The coach will take you diving. If you feel uncomfortable in the water for the first time, you can float up, adjust your breathing, and then go into the water. Listen to the instructions of the diving instructor when you are underwater.

5. Prevention of drowning hazards, knowledge and self-help knowledge

Self-help method

In order to prevent drowning accidents, the fire department hereby reminds parents to constantly raise their awareness, strengthen supervision over their children and educate them not to swim in the water without permission. Schools should carry out safety education activities to prevent drowning before holidays, so that students can understand the causes of drowning, remind students to strengthen prevention and prevent drowning accidents. In the event of drowning, people unfamiliar with water can hold their breath immediately after falling into the water, relax their limbs and try to keep their heads backward. As long as you don't struggle wildly, your body won't lose its balance in the water, so your nose and mouth will surface first, and you can breathe for help at this time. When breathing, try to inhale through your mouth and exhale through your nose to prevent suffocation. Swimmers, such as calf or leg cramps, don't panic, keep calm, bend the toes of cramped legs back with their hands to relieve cramps and call for help.

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Drowning, people unfamiliar with water can immediately hold their breath, relax their limbs and do their best after drowning.

Try to lean your head back. As long as you don't struggle, the human body is in the water.

You won't lose your balance, so your nose and mouth will surface first, and that's it.

Breathe and call for help. When breathing, try to inhale through your mouth and exhale through your nose to avoid choking.

Swimmers, if they have cramps in their calves or feet, don't panic and stay calm.

Bend the toe of the cramped leg backwards by hand to relieve the cramp and call for help at the same time.

Help!

Be careful when rescuing drowning people-

Just because you can swim doesn't mean you can save lives. Even if the water is good, once someone falls into the water,

You can't blindly go into the water to rescue. When drowning, the drowning person often panics and is at a loss.

If you struggle hard, you will inevitably regard the rescuer as a lifeline and die.

Catch it so that rescuers can't get away. Many teenagers, especially boys, lack rescue skills.

Yes, when you see that your partner is in danger, you will jump directly to save people. As we all know, in water.

People who struggle are often very powerful. Instead of saving others, they take their own lives.

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People unfamiliar with water can hold their breath immediately after drowning, relax their limbs and try to keep their heads back. As long as you don't struggle wildly, your body won't lose its balance in the water, so your nose and mouth will surface first, and you can breathe for help at this time. When breathing, try to inhale through your mouth and exhale through your nose to prevent suffocation. Swimmers, such as calf or leg cramps, don't panic, keep calm, bend the toes of cramped legs back with their hands to relieve cramps and call for help.

Be careful when rescuing drowning people-

Just because you can swim doesn't mean you can save lives. Even if the water is good, once someone falls into the water, you can't blindly go into the water to rescue him. When drowning, drowning people often panic and struggle with their hands and feet. In a hurry, it is inevitable that the rescuer will be caught as a lifeline, so that the rescuer can't get out. Many teenagers, especially boys, lack rescue skills. When they see that their companions are in danger, they will jump directly to save lives. As we all know, people who struggle in the water are often very powerful, but they can't save others but kill themselves.

Approach the drowning man from behind.

When approaching the drowning person to carry out rescue, we must master the correct rescue posture, that is, approach from the drowning person's back, put one hand into the armpit of the opposite side from his chest, clamp his head tightly on his chest, paddle with the other hand and drag it to the shore by backstroke. In case of being caught by the drowning person, the rescuer can hold his breath and sink, so that the drowning person will struggle upwards and instinctively let go; If you hold it from behind, the rescuer can break his fingers outward; If the neck is locked, tighten the jaw immediately; if

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If you are hugged from the front, you must first stretch your body upwards, then squat down, and your arms will be forced to break free.

There are three things to do after being rescued ashore.

1, remove impurities from mouth and nose. The clothes and belts of the drowning person should be untied quickly, and the silt, weeds, foam and vomit in the mouth and nose should be removed to keep the upper respiratory tract unblocked. If there is an obstruction in the throat of the drowning person, put the drowning person face down and pat the obstruction out of the trachea with force behind his back.

2. control water. The common method is that the rescuer kneels on the ground with one leg and the other leg, puts the abdomen of the drowning person on his knee, and then holds the drowning person's head with one hand.

Mouth down, you can press the abdomen of the drowning person with your knees to drain the water. You can also pick up the waist and abdomen of the drowning person, let his back face up and his head droop and pour water. When you meet a lighter child, you can hang him upside down and press his abdomen to drain water.

3. Cardiopulmonary resuscitation. If breathing and heartbeat stop, cardiopulmonary resuscitation (CPR) is needed immediately, that is, artificial respiration plus chest compressions. If you can't or won't do artificial respiration, you can only do chest compressions. Hope to adopt

6. The principle of homemade submarine

The principle of submarine is realized by changing its own weight. Submarine. It has several water storage tanks. When the submarine is about to dive, water is injected into the water storage tank to increase the weight of the submarine to exceed its displacement, and the submarine will dive.

Force analysis of two dynamic processes of object sinking and floating in liquid. As we all know, submarine is a kind of military ship, which can dive underwater for reconnaissance and attack.

However, many students are not clear about the working principle of submarines, and some even mistakenly think that submarines sink after sinking into the water; Until it sinks to the bottom of the sea, in fact, after the submarine sinks into the water, the volume of boiling water will not change, and the buoyancy it receives will remain unchanged.

Controlling its diving depth is achieved by changing the amount of water in the water tank (that is, changing the gravity). When the amount of water in the water tank is constant, the submarine is suspended to a certain depth, instead of sinking.

Extended data:

Submarine characteristics:

You can use the water layer to cover hidden activities and carry out sudden attacks on the enemy; It has great self-sustaining, endurance and operational radius, can be far away from the base, can fight independently for a long time, in a large ocean area or even in the enemy sea area, and has strong assault force; It can launch missiles, torpedoes and mines underwater and attack targets at sea and on land.

Submarine supporting equipment is diverse and technical requirements are high, and there are not many countries in the world that can develop and produce submarines by themselves. The submarine has poor self-defense ability and lacks effective air observation means and air defense weapons; Underwater communication is difficult to achieve two-way, timely and long-distance communication; The detection equipment has short range and limited observation range, which is easily influenced by the environment and difficult to grasp the enemy's situation.

Conventional power submarines have low underwater speed and extremely limited endurance at high speed. When charging, it must be in the state of snorkeling navigation and easy to be exposed. The self-sustaining power of conventional submarines is generally about 45 days, and the highest record of nuclear submarines can reach 90 days. It is mainly composed of hull, control system, power plant, weapon system, navigation system, detection system, communication equipment, underwater acoustic countermeasure equipment, life-saving equipment and living facilities.

Baidu encyclopedia-submarine principle

Baidu encyclopedia-submarine

7. Knowledge of drowning prevention safety education

First of all, you should keep calm and never struggle with your hands and feet, which can reduce the entanglement of aquatic plants and save your strength. The correct way to save yourself is to hold your breath immediately after falling into the water, then relax your limbs and lean your head back as far as possible. As long as you don't struggle at random, your body won't lose its balance in the water. In this way, your nose and mouth will surface first, and you can breathe and call for help. When breathing, try to inhale through your mouth and exhale through your nose to avoid choking. When you feel tired after swimming for a long time, you can change to backstroke, paddling gently with your hands and feet, so that your nose and mouth can easily float on the water, and give first aid on the spot.

(A) can not swim to save themselves

(1) Don't panic after falling into the water. You must keep a clear head. (2) Calmly put your head back, mouth up, and expose your nose and mouth out of the water, then you can breathe. (3) Take a shallow breath, take a deep breath, and try to keep your body floating on the water and wait for others to save you. (4) Remember: Never raise your hand or struggle hard, because it will easily make people sink.

(2) the swimmer's self-help

(1) Drowning is usually caused by calf gastrocnemius spasm. Calm down and call for help in time. (2) Hold the body in a ball and float to the surface. (3) Take a deep breath, immerse your face in the water, and pull the thumb of the spasmodic (cramped) lower limb forward and upward, so that the thumb can be lifted upward, and continue to exert force until the severe pain disappears and the cramp naturally stops. (4) After the attack, the same part can cramp again, so you should swim to the shore to relieve the pain, and it is best to * * hot compress the affected area after landing. (5) If the wrist muscles cramp, you can bend your fingers and stretch them up and down, take a supine position and swim with your feet.

(3) Mutual assistance

(1) The rescuer should be calm, take off his clothes and trousers as much as possible, especially shoes and boots, and swim to the drowning person quickly. (2) For the exhausted drowning person, the rescuer can approach from the head. (3) For the conscious drowning person, the rescuer should approach from behind, hold the head and neck of the drowning person from behind with one hand and swim to the shore with the other. (4) If the rescuer is not skilled in swimming, it is best to carry a life buoy, a wooden board or use a boat to rescue him, or throw ropes and bamboo poles. So that the drowning man can catch it and drag it ashore. (5) During rescue, attention should be paid to prevent the drowning person from clinging and being in danger. If you are hugged, don't drag the other person. You have to let go, let yourself sink, let the drowning person let go, and then go to rescue.

(4) On-site medical or first-aid witnesses.

(1) When the first witness found the drowning person, he immediately called 120 or the emergency number of the affiliated hospital to request medical first aid; (2) After the first witness or emergency medical personnel arrive at the scene, first rescue the drowning person ashore; (3) Immediately remove the silt, weeds and vomit in the mouth and nose of the drowning person, and open the airway to provide oxygen. (4) Carry out controlled water treatment (pouring water), that is, quickly put the patient on the thigh where the rescuer bends his knees, head down, and then press his back to force the water inhaled into the respiratory tract and stomach to flow out. The time should not be too long (1 minute). (5) Carry out cardiopulmonary resuscitation at the scene, put it in an ambulance as soon as possible, and quickly transport it to a nearby hospital. As a rescuer, it must be remembered that all people who are in drowning shock, no matter what the situation, should continue cardiopulmonary resuscitation from the time of discovery. Adjust your breath, relax yourself, swim to the shore or float on the water after a short rest and wait for rescue.

8. I want diving knowledge, short and comprehensive, 50

Snorkeling

We divide it into activities that only float on the surface of the water and don't dive into the water, which is called "floating", and diving activities that hold their breath into the water are called "holding their breath".

Inflatable diving

The so-called "air diving" means that divers can get gas supply during diving, and it can also be divided into two categories, one is "self-supporting air diving" and the other is "air diving".

Divers dive into the water with the gas used in underwater activities, which is generally called "scuba diving". Air-supply diving is that divers transport air from the water surface to divers with the help of an air supply pipe when they are underwater, which is also called "water-supply diving". In recent years, this kind of water supply diving activity has been held in various famous holiday coastal areas in the world for tourists to experience the underwater world.

Scuba diving

In order to dive continuously underwater for a long time, people have to carry cylinders filled with compressed air into the water, which is scuba diving.

At this time, the diver inhales the air in the cylinder. People often mistakenly think that this kind of gas cylinder carried by divers is an oxygen cylinder. In fact, this understanding is wrong.

Scuba diving allows you to swim freely in the water, but it will surface before the limited air is exhausted.

9. knowledge of preventing drowning

There are many online. I've been looking for work materials for the past two days.

Summarized a little common sense and shared it.

First, the cause of drowning death

It is mainly due to the inhalation of a large amount of water in the trachea that hinders breathing, or because of the strong spasm of the larynx and the closure of the respiratory tract.

Second, symptoms

The drowning person's face is bruised, his eyes are bloodshot, and his mouth, nostrils and trachea are full of blood bubbles. Cold limbs, weak pulse, even convulsions or respiratory heartbeat stop.

Third, self-help and rescue.

When drowning happens, if you are unfamiliar with the water, you can take the method of self-help: in addition to calling for help, take a supine position and tilt your head back so that your nose can breathe out of the water. Shallow exhalation and deep inhalation. Because when inhaling deeply, the body specific gravity drops to 0.967, which is slightly lighter than water, and can surface (when exhaling, the body specific gravity is 1.057, which is slightly heavier than water), so don't panic at this time, and don't raise your arm and flap it left and right to make your body sink faster.

Swimmers, if they have cramps in their calves, should keep calm, take a backstroke posture, bend the toes of the cramped legs backwards with their hands to release the cramps, and then slowly swim to the shore.

To rescue the drowning man, swim to the vicinity of the drowning man quickly, observe the position clearly and rescue him from the rear. Or throw boards, lifebuoys, long poles, etc. So that the drowning person can climb ashore.

After the water rescue:

First clean up the silt and sputum in the mouth and nose of the drowning person, take off the false teeth, and then control the water. The rescuer kneels on one leg, puts the drowning person on the rescuer's thigh, and uses * * * to discharge the water in the drowning person from the trachea and mouth. In some rural areas, the drowning person will lie on the back of the cow, with his head and feet suspended, driving the cow to walk, thus controlling water and playing the role of artificial respiration. If the drowning person's breathing and heartbeat have stopped, give mouth-to-mouth artificial respiration immediately and perform chest compressions at the same time.

4. How to prevent drowning

Swimming is one of teenagers' favorite sports. However, if you are not prepared, lack safety awareness, panic when you encounter an accident, and you can't save yourself calmly, it is easy to cause drowning casualties.

In order to ensure the safety of swimming and prevent drowning accidents, the following must be done:

1, don't go swimming alone, let alone in places where you don't know the bottom and water conditions, or dangerous places where drowning casualties are likely to occur. Choose a good swimming place and have a clear understanding of the environment of the place, such as whether the reservoir and bathing place are sanitary, whether the water surface is flat, whether there are reefs, undercurrents, weeds and the depth of water.

2. Swimming must be organized under the guidance of teachers or people familiar with water, so as to take care of each other. If a collective organization goes swimming, it is necessary to count the number of people before and after launching and designate lifeguards for safety protection.

Pay attention to your health. People who are prone to cramps in limbs should not take part in swimming or swim in deep water. Get ready before you go into the water and exercise first. If the water temperature is too low, wash your body with shallow water first, and then go swimming after getting used to the water temperature. Students with dentures should take them off to prevent them from falling into the esophagus or trachea when choking.

4. Be self-aware of your water quality. Don't try to be brave after entering the water. Don't dive and snorkel rashly, and don't fight with each other, lest you drown by drinking water. Don't swim in rapids and whirlpools, let alone drink and swim.

5. If you suddenly feel unwell during swimming, such as dizziness, nausea, palpitation, shortness of breath and so on. , should immediately go ashore to rest or call for help.

6, in swimming, if the calf or leg cramps, don't panic, you can kick or jump hard, or hard * * *, pull cramps, and call for help from your partner.

7. When a drowning accident occurs in swimming, the first aid on the spot is urgent, and cardiopulmonary resuscitation is the most important. After the drowning person is rescued ashore, the vomit, sediment and other impurities in the oral cavity and nasopharyngeal cavity should be removed immediately to keep breathing smooth; The tongue should be pulled out to avoid backward turning and blocking the respiratory tract; Raise the abdomen of the drowning person so that his chest and head droop, or hold his legs, put his abdomen on the rescuer's shoulder, and do the action of walking or jumping to "pour water". Restoring the drowning person's breathing is the key to the success of first aid. Artificial respiration should be carried out immediately, and mouth-to-mouth or mouth-to-mouth artificial respiration can be used. At the same time of first aid, you should be sent to the hospital for treatment quickly.