Popular science knowledge propaganda handwritten newspaper is concise and beautiful.

1, fireflies can emit light because there are luminous bodies at the end of their abdomen, which are filled with many phosphorus-containing luminous substances and luminescent enzymes, so that fireflies can emit flashing light.

The purpose of fireflies is not only lighting, but also courtship, vigilance and trapping. This is also a communication tool for them. Different kinds of fireflies emit light in different ways, frequencies and colors, so they can convey different information.

2. Don't look at the tail of Yi Mouse! When the squirrel jumps around the tree, its tail plays a great role. It can keep balance when the squirrel jumps to the tree to avoid falling and being injured. In addition, this big tail can play a more protective role in winter, tightly surrounding the squirrel's body, which is convenient and practical.

Looking at the sea, it is often found that the sea water is blue-green. However, when you pick up the sea water, you can only see it as transparent and colorless as old water. It turns out that the seawater itself is not much different from the water we touch every day, and it is also transparent. The green we see is actually a phenomenon caused by the ability of seawater to absorb light. Only green light can be absorbed and reflected by seawater; When the seawater is deep, the green light is also absorbed, and the seawater looks blue.

4. The cause of leaf discoloration is related to the chemical chlorophyll. When autumn comes, the days are shorter and the temperature is lower than that in summer, so the leaves stop producing chlorophyll, and the remaining nutrients are transported to the trunk and roots for storage. Leaves lack green chlorophyll and other chemical pigments appear at the same time, so we often see yellow and brown leaves.

5. It's autumn. The leaves evaporate more water than in summer, but the roots absorb less water than in summer. In order to reduce the water loss of trees, stem cells began to form separation layers. When the nutrients leave the leaves completely, the separation layer separates the leaves from the trunk and leaves fall off.

6. The moon, commonly known as the moon, also known as the lunar moon, is the only natural satellite of the earth and the closest celestial body to the earth. The average distance to the moon is 38440 1 km. This distance is about 10 times of the equatorial circumference of the earth. The orbit of the moon is elliptical, with an average distance of 363,300 kilometers at perigee and 405,500 kilometers at apogee. The moon is 3476 kilometers in diameter, which is about 3/ 1 1 of the earth's diameter. The surface area of the moon is about114 of the surface area of the earth, slightly smaller than that of Asia. The moon is only 1/49 the size of the earth. The mass of the moon is about 1/8 1.3 of the mass of the earth. The average density of lunar material is 3.34 grams per cubic centimeter, which is only 3/5 of the density of the earth. The gravitational acceleration of a free fall on the lunar surface is 1/6 of that of the earth. The escape speed on the moon is about 2.4 kilometers per second, which is about 1/5 of the escape speed on the earth.

The moon makes an elliptical motion around the earth, and it also accompanies the earth to revolve around the sun once a year. The moon is not only influenced by the gravity of the earth, but also by the gravity from the sun, so it has a very complicated orbital motion. The moon itself is neither luminous nor transparent, but it can reflect sunlight. Because the relative positions of the sun, the earth and the moon are constantly changing, the illuminated part of the moon seen by observers on the earth is also constantly changing, resulting in different visual shapes. This is called the moon phase.