10 Interesting Little Science Facts

1. Why in Romance of Three Kingdoms did two armies fight each other before battle?

In era of edged weapons, morale of two opposing sides is much more important than difference in strength and weapons. Thus, it is also a method of warfare to send generals to fight one on one before large-scale battles. If they win, their morale will increase significantly. Even if they fail, they will only lose one general.

2. Why is density of Sun so low?

The temperature on surface of Sun reaches 6000 °C and above. At this high temperature, all matter is in a gaseous state, so Sun's density is low, with an average density of about 14 grams per cubic centimeter, slightly denser than water on Earth.

3. How many degrees can a star's temperature reach?

Let's take sun as an example. The temperature at center of sun is about 15 million °C. For a star of a certain mass, temperature of its core always gradually increases with age. According to some astronomers, temperature of a star's core can reach a maximum of 6 billion °C, which is beyond our imagination.

4. How do our eyes see things?

The outer layer of human eyeball is a colorless and transparent cornea, similar to a camera lens. In center of eye, there is a small round hole called pupil, through which light from outside world enters retina at bottom of eye. When light is too bright, pupil slowly constricts; when light is too weak, pupil automatically dilates. There are countless photoreceptor cells on retina, which, receiving light stimulation signals, convert these signals into nerve impulses and transmit them to visual center of cerebral cortex along optic nerve.

5. How do plants protect themselves?

Animals continue to attack plants, but green plants are not extinct. Therefore, plants can also protect themselves. Some of them use "chemical weapons"; some plants have thorns that make many animals stay away; some plants use scent to protect themselves. drive away enemies, some plants can also "alert".

6. Why should you drink more water when you have a fever?

When a person is sick and has a high temperature, microbes in body will constantly release toxins, threatening health. If you drink more water during this time, you will urinate more, and more urine will flush out toxins. In addition, after drinking a lot of water, people will sweat more, so that body heat can be easily dissipated, so that body temperature can be lowered.

7. Why are tears salty?

When people eat vegetables, they always have salt. After these salts enter human body, they are absorbed into various parts. Therefore, while it is excreted from body, for example, with sweat, urine, etc.etc., it contains salt, like a tear. That's why tears are salty.

8. How are teeth divided?

The front front teeth are like shovels, they cut food well; lateral teeth are fangs that are specially used to tear off large pieces of food; Crumble and chew food.

9. Do birds fart?

Humans and other mammals have gas-producing bacteria in their guts to help digest food, but birds do not. "It's not that birds don't fart, it's that they don't," says veterinary expert. Birds are anatomically and functionally capable of removing gas in other ways.

10. What does it mean when a dog shakes its tail left and right?

When dog is in a good mood or shows curiosity, tail wags to right, if dog is experiencing negative emotions or even fear, tail wags to left. This representation is result of a division of labor between their left and right hemispheres.