Hello children, I am the blue bean of the creation space, let's guess a riddle first: shake the head and swing the tail without leaving the water, and the wings spit bubbles can not fly. Can you guess what it is?
Fish are the oldest vertebrates, with about 32,000 species of fish found in the world, and new species are constantly being discovered. Two-thirds of the world's fish live in the oceans, with the rest living in fresh water.
China is a country with relatively rich species, children, do you know how many species of fish there are in our country? Although there are not many common fish in life, at the current research stage, about 3,000 species of fish have been found in China!
Fish, accompanied by human beings through more than 5,000 years of history, and we have formed an indissoluble relationship. For example, because of its unique ornamentality, it has become an important ornamental pet in human daily life, and it has also made great contributions in the field of biomimicry, so what help does fish provide for scientific research? Let's take a look!
Fish and submarines
Scientists have found through research that the reason why fish can float and sink freely in the water is because they have a balloon-like thing in their bodies, called fish maws, and fish can control the sinking and floating by controlling the amount of air in the swim bladder.
Step inside the submarine
Submarines come in a wide variety, shape, and power. It can use the cover of the water layer to carry out covert activities and carry out surprise attacks on the enemy. It can go to any coast of the world and is not discovered; the submarine is equipped with air regeneration, atmospheric control, radioactive pollution detection, temperature and humidity regulation system, living and living and eating, water, lighting, excretion, medical and other facilities, used to maintain a suitable living and activity environment in the boat, to ensure the health of the crew, even in the Arctic and South Seas, ice and frost can not hurt the submarine crew; submarines have a large self-sufficiency, endurance and combat radius, can be away from the base, It fights independently in the enemy's sea area for a long time and in larger marine areas; it has a strong assault power, which can effectively resist the enemy and destroy and sink ships on the surface; submarines can launch missiles, torpedoes and lay mines underwater to attack sea and land targets.
Because of its unique advantages such as safety and privacy, submarines play an important role in the military field, and are also widely used in other fields, such as: marine scientific research, rescue of property, exploration and mining, scientific detection, maintenance of equipment, search and rescue, submarine cable maintenance, underwater tourism, academic investigation, etc.
Just now we talked about the relationship between fish and submarines, so what is the mystery in submarines? The submarine has a maw-like structure, the ballast tank, and by simulating the function of the swim bladder, the submarine has achieved floating and sinking. When the crew fills the tank with water, the submarine becomes heavier and gradually sinks. When the tank is filled with water, the submarine's gravity is equal to buoyancy, it can be suspended in the water, and when the compressed air discharges the water, the gravity is reduced, so that the submarine floats.
Small experiments in science
Do the children understand? Speaking of gravity and buoyancy, I thought of a fun little experiment – obedient balloons, come and see with me!
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Video "Obedient Balloon"
Principle revealed: the balloon is equivalent to the balloon, when the use of syringe injection, the pressure in the bottle becomes larger, the balloon under the action of pressure, the volume becomes smaller, so the buoyancy becomes smaller, the gravity is greater than the buoyancy, the balloon sinks; when the syringe pumps, the balloon volume becomes larger, so the buoyancy becomes larger, the buoyancy is greater than the gravity, and the balloon floats.
Isn't it very interesting, children follow the blue beanie, using the items around them to make their own science and technology small toys!
More wonderful recommendations from previous issues
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At present, the "online small classroom of Chuang space" Douyin account has been officially launched, interested parents and children can log on to the "Douyin APP" platform, search and pay attention to the "online small classroom of Chuang space", we will continue to launch science small talents - Dr. Lan laboratory series, visitor small talents - explorer workshop series, detective small masters - A + detective agency series and other popular science interactive small videos.
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