Why eat meat ... delicious?

People love eating meat from . more than 2 million years ago. Katharine Milton, an anthropologist at the University of California at Berkeley, explains: You can't go dozens of miles every day with a belly full of vegetables.

Why do people like to eat meat?

With high protein content, meat helps build muscle and is also a source of sodium, an ion is important for communication between cells and signal transmission through the nervous system. Meat also provides fat to produce hormones for organs. With time evolution, the body has linked the fat, protein and salty taste of meat to high nutritional value. Since then the smell of barbecue is irresistible. Meat also has many ribonucleotide molecules that react with the glutamate amino acid in meat and many other foods, stimulating the tongue and creating umami taste, also known as 'the taste of meat' , discovered by a Japanese scientist. 100 years ago.

Why are clothes still dry even without sunshine?

The water in the fabric fibers escapes as vapor, but how can this happen when temperatures are much lower than 100C? Thanks to the difference between the two phenomena of boiling and evaporation.

In liquid water, the molecules are very weak. When heated, water is energized, causing it to move and raise temperature. By 100C, when the force is strong enough to break weak bonds, the water leaves liquid and dissolves in the air - that is boiling.

Under 100C, water gradually turns into steam.Evaporation occurs on the surface of the liquid, where the molecules are weakly bound because there is no pressure from above. So even at 100C or 200C, some water molecules still find enough energy to fly away. But the secret of the phenomenon of evaporation first is the wind . The wind chased away the steam. Without wind, steam molecules still cling to the fabric, move, collide with the air and some return to the fabric, though after a while they also fly away. Therefore, even without sunshine, clothes can still dry, as long as there is wind.

Why don't you feel the Earth spin?

Because we don't have . speed gauges. In the car, if running straight at regular speed, only the scenery running in the opposite direction and the shock between the wheel and the road surface indicate that you are moving, and when you win, you feel you are thrown forward. . What we feel in that case is just a change in speed and direction.

So is the Earth. It was a giant carriage, spinning at a speed of 107,000 km / h around the Sun. And because it still revolves around itself, it must add 1,600 km / hour. But because the speed is constant , you don't feel anything.

Why? Because rotation is a continuous change of direction . Due to its small size, people only see straight lines when driving on a virtual circle with a circumference of 40,100km of Earth. But why doesn't the wind blow back as if it was a car? Because the surrounding air also turns around .

In the polar regions do people weigh more when in equatorial regions?

When you are in two polar regions, your weight will be higher. But that's just fake fat. Because no matter where you are, your volume remains unchanged. The change is the weight , the gravity of the Earth impacts on yourself. Weight (P) and mass (m) are related in the formula P = mg, where g is the gravitational acceleration. The value of g varies depending on the position because the Earth is not completely round.

At the equator the Earth radius is longer than 21km. The increase in the distance between the center of the Earth and yourself will reduce the amount of g, making weight decrease. Second, when you are at the equator, you will be spinning faster at the two poles. The value of g here is 9.78 m / s2 compared to 9.83 m / s2 at the pole. When making scales people use the average g-value of Earth at 9.81 m / s2.

Why does the balloon fly . fly up?

The same cause of floating ships: the force of Archimède. In the atmosphere, the Archimède propulsion is 1.2kg per cubic meter. Meaning to bring a person weighing 80kg into the air, need to have a 60.7m3 ball. This is not including the weight of the ball and the injected gas. Must be light gases, helium or hydrogen, for example.

Can prevent earthquakes?

Earthquakes are caused by increased pressure in the Earth's heart . Energy is released suddenly by strong movement and collision between tectonic plates, equivalent to the energy of thousands of atomic bombs. The shockwave, which is the high pressure area, can lie hundreds of kilometers underground and run hundreds of kilometers. Hoping to limit the magnitude of the earthquake, by detonating it before the pressure becomes too strong, is still a fantasy.