1. A list of idioms describing wind, rain, thunder and electricity. The wind defends against the wind, shelters from the wind, stops the wind, stops the meteor, makes waves, makes waves, catches the wind, catches the wind, catches the moon, catches the wind, catches the shadow, chases the wind, chases the wind, chases the shadow, chases the wind, chases the wind, chases the electricity, chases the wind, chases the rain, chases the wind and catches the storm every day.

List of idioms of rain: shelter from the wind and rain, sudden storm, sudden storm, sudden storm, storm, violent storm, violent storm, violent storm, sudden storm, sudden storm, sudden storm, sudden storm, sudden storm, sudden storm, sudden storm, sudden storm, sudden storm, sudden storm, sudden storm, sudden storm, sudden storm, sudden storm, sudden storm,

The list of electric idioms is about clouds, electricity, wind, wind, electricity, fast current, fast current, fast current, fast current, fast current, fast current, fast current, fast current, fast current, fast current, fast current, fast current, fast current, fast current, fast current, fast current, fast current.

Lei's idiom list is thunderous, thunderous and thunderous. It's thunderous, thunderous, thunderous, thunderous, thunderous, thunderous. Although the raindrops are small and thunderous, the kettle can't move and the fire is thunderous. Thunder rumbles and mosquitoes rumble. Thunder is thunderous, and the yellow bell is destroyed. Wolframine cheered, snored like thunder, and the thunder axe thundered. Thunder and thunder guns are popular. Thunder and lightning, cicadas thunder. Don't jump across the line, don't dare to cross the line.

2. Describe what radar is in twenty words, which is called "radio positioning".

It is an electronic device that uses electromagnetic waves to detect targets. Radar, the transliteration of English radar, comes from the abbreviation of radio detection and ranging, which means "radio detection and ranging". It finds targets by radio and determines their spatial position.

Therefore, radar is also called "radio positioning". Radar uses electromagnetic waves to detect targets.

The radar emits electromagnetic waves to illuminate the target and receives its echoes, thus obtaining information such as the distance from the target to the electromagnetic wave emission point, the rate of change of distance (radial speed), azimuth, altitude and so on. Mostly used in: military combat command and civil navigation guidance, first used in World War II. Radar functions like eyes and ears. Of course, it is no longer a masterpiece of nature, and its information carrier is radio waves.

In fact, visible light and radio waves are essentially the same thing, both electromagnetic waves, and the propagation speed in vacuum is the speed of light C, the difference lies in their respective frequencies and wavelengths. Its principle is that the transmitter of radar equipment emits electromagnetic wave energy to a certain direction in space through an antenna, and the object in this direction reflects the electromagnetic wave it encounters; After receiving this reflected wave, the radar antenna sends it to the receiving equipment for processing, and extracts some information of the object (the distance from the target object to the radar, the change rate of distance or radial speed, azimuth, altitude, etc.). ).

3. What are the words for bat and radar in the fourth grade of Chinese to make them fly at night, immediately change the flight direction and think seriously: First, blindfold the bat? Is bat's eyesight particularly good? Three experiments were done.

Now, as long as you observe carefully and serve people, ultrasound will come back to the article in the same way when it encounters obstacles, just like we humans see things? In order to solve this mystery, scientists use it to find objects flying in the sky. The second is to plug the bat's ears. The third is to seal its mouth to avoid objects. Instead, it can emit something called "ultrasonic waves" through its mouth. As a result, scientists found that bats fly in the dark. It turns out that their eyesight is not particularly good. What's going on here? They won't hit any obstacles, and the secrets of nature will be solved by you. Radar is widely used in people's lives, and bats receive echoes.

Scientists invented radar according to this principle. After reading this story, I feel that nature is like a human teacher.

4. The bat and radar 12 new words and three "bats and radar" words 1 1 bat and radar (bat) catches (catches) (hunts) (preys) (mantis catches cicada, yellowbird follows) (catches the wind and shadows) moth (moth) (cabbage moth