Sunlight shining on our skin will dilate subcutaneous blood vessels, increase blood flow, increase excretion and resistance of toxic substances, increase secretion of saliva and gastric juice, strengthen gastro motility -intestinal and will promote appetite and digestion.
The skin can also produce vitamin D from certain chemicals, such as ergot and cholesterol, under sun exposure. These vitamins, calcium and phosphorus, are important components of our bones. Without them, we will suffer from rickets.
Sunlight is even more important for children, as they grow and develop quickly, and bone development plays an important role in supporting the entire body when there is a shortage of sun so that the body is formed. vitamin D, child development is bound to cause serious problems.
Green plants can convert solar energy into chemical energy, and plants can be eaten by animals, and herbivores are eaten by carnivores. Therefore, various organisms in the environment are connected based on nutritional relationships, becoming food. chain.
The sun's ultraviolet rays have a strong sterilizing power. Generally, bacteria and some viruses will be killed after being exposed to sunlight for half an hour or a few hours.
Bring light.
The sun is vital for humans. The circulation of the Earth's atmosphere, the rotation of day and night and the four seasons, and the changes in the Earth's temperature and temperature are all the result of the action of the sun. For astronomers, the Sun is the only star whose surface details can be observed. By studying the sun, humans can infer the properties of other stars in the universe. Actually, the sun is the only star for which we can see surface details. Most of what humans know about stars comes from the sun.
List of examples: conversion between two internal energies, light energy, mechanical energy, electrical energy and chemical energy
1 Electric light emits light: electrical energy is converted into light. Energy;
2. Battery powered; chemical energy is converted into electrical energy;
3. The motor drives the machines: electrical energy is converted into mechanical energy; >4. The generator generates electricity; mechanical energy is converted into electrical energy;
5. The electric furnace boils the water: the electrical energy is converted into internal energy;
6. energy is converted into sound energy;
7. Gasoline engine Mechanical: chemical energy is converted into mechanical energy;
8. Television: l'éelectrical energy is converted into light energy;
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9. Microphone recording: sound energy is converted into electrical energy;
10. Wind turbines generate electricity; mechanical energy is converted into electrical energy;
11. supply: light energy is converted into electrical energy;
12. Rocket launch: Chemical energy is converted into kinetic energy;
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13. Hydroelectric generation: Mechanical energy is converted into electrical energy. converted into electrical energy;
14. Carriage of people: chemical energy is converted into mechanical energy;
15. The heat of friction is converted into internal energy;
< p>16. Solar cooker: light energy is converted into internal energy;17. Trumpet Sound: Electrical energy is converted into sound energy;
18. in sound energy and light energy;
19. Burning firewood;chemical energy is converted into light energy;
20. Plant photosynthesis: Light energy is converted into chemical energy.
Internal energy into light energy: objects emit light at high temperatures
Internal energy into mechanical energy: the process of expanding the volume of gas during the power stroke of a heat engine (the process is changed after the conversion of chemical energy into internal energy)
Internal energy into electrical energy: I only know indirect conversion (production of thermal energy), direct conversion should be possible but it is impossible to convert 100%
Internal energy to chemical energy: Ba(OH)2+NH4Cl reaction (endothermic)
Light energy to energy internal: sunlight
Light energy into mechanical energy: solar sail (light generates pressure)
Light energy into electrical energy: solar panels
Enelight energy into chemical energy: AgBr is decomposed by light
Mechanical energy into internal energy energy: the cursor goes from movement to rest on the raw plate
p>Mechanical energy into energy light: (empty)
Mechanical energy into electrical energy: generator
< p>Mechanical energy into chemical energy: (empty)Electrical energy into internal energy: electric blanket
Electrical energy into light energy: light bulb
Electric energy into mechanical energy: electric motor
Electric energy into chemical energy: chemical effect of electric current: electrolysis of 'a solution of NaCl
Chemical energy into light energy Internal energy: combustion of charcoal
From chemical energy to mechanical energy: power stroke of an engine thermal energy
From chemical energy to electrical energy: primary battery
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