"Natural Science 4" is an interactive encyclopedia that includes scientific information in the understanding of fourth grade students, wonderfully illustrated and animated.
.
www.edituraedu.ro
.
* Chapter 3 Lesson 17 *
* The sun, source of heat and light *
The sun is just one of over 100 billion stars that make up our galaxy, the Milky Way. Its diameter is 100 times that of the Earth. It would take about 1,300,000 Earth planets to fill the volume of the Sun.
The sun formed from a cloud of gas and dust. He is a huge ball of hot gas, a sphere of hydrogen, that produces an enormous amount of energy. It comes to the surface as light. The Sun's rays travel through the universe at an incredible speed of 300,000 km/s. Light from the Sun takes 8 minutes to reach the Earth.
Astronomers consider our star to be a yellow dwarf compared to other stars. In contrast to these, the Sun is much closer to us, if we can call the distance of 150 million kilometers between the Earth and this celestial star that way. This is one of the reasons why we see it so brightly. The sun is our star, it warms us, lights us and gives us energy. Without it, our Earth would be a dark, lifeless, cold ball. Without it, the earth's temperature would be 270°C and no life would be possible.
Plants and animals need sunlight. Light energy allows plants to feed and grow. They prepare their food in the leaves, with the help of the light received from the Sun. Following this process, it releases oxygen, so necessary for humans and animals.
In the light of the Sun, our skin produces vitamin D. This contributes to the normal growth and development of the body and influences the fixation of calcium in the bones of the body.
Through its heat, the Sun heats the air and circulates the air masses that "ventilate" the planet, and it also evaporates water and helps form the clouds that bring rain. It is important to know that it kills many microbes with its ultraviolet rays. Let's not forget the wonderful aurora borealis, one of the most beautiful phenomena that can be observed on our planet. Solar wind particles that form during solar flares enter the earth's atmosphere. Upon impact with the atmosphere, a blue, green or red light is emitted.
If you could talk to the Sun, what would you say to it in the morning when it rises? But in the evening, when it goes down?