Qiao Bao and Qiao's father wrote signs and hung them on the faucet, and Qiao's mother said, "In that case, Qiao Bao, how much do you know about the water cycle?" ”

"Water... Water cycle? What is the Water Cycle? ”

Qiao Bao scratched his head suspiciously, he really didn't know, "Qiao Bao doesn't know, Mom tell Qiao Bao..."

"Shall we visit the exhibition hall on the theme of the water cycle? I saw it when I came. ”

Qiao's mother pointed to a nearby exhibition hall.

"Okay—"

Qiao Bao followed Qiao's mother and Qiao's father with great interest, and came to the third floor of the next building, which is indeed a water-themed exhibition hall, which has models of water plants, as well as models of rivers, lakes and seas.

"There's really water..."

Qiao Bao walked over to a round model of the lake and reached out to secretly touch the water inside.

"Huh! Qiao Bao! You can't just touch it! ”

Qiao's mother hurriedly grabbed Qiao Bao's hand and wiped his wet fingers.

"Everything in the exhibition hall is for people to visit, you can't touch it casually, and you see, there are lights in the model, which means that it is electrified, and water conducts electricity, and if there is a leakage somewhere, you will be electrocuted."

"Electrocution?"

Qiao Bao shuddered with fright, "Will you die of electrocution?" If you die, there is nothing left, and you can't see your parents anymore, then Qiao Bao will get lost! ”

"So, Qiao Bao can only see with his eyes, and he can't move his hands."

Qiao's father hugged Qiao Bao, "It's a lot clearer this way, isn't it?" ”

"Yes."

Qiao Bao saw that above the large platform representing the land, there was a large light bulb representing the sun, and there was plastic wrap next to it, as well as small cotton balls representing clouds.

"When the sun shines, the water evaporates and becomes water vapor, which rises and becomes small droplets, which condense into clouds.

The small droplets are supported by the air flow below, and the rising air flow is constantly transporting water vapor from below into the clouds.

The small droplets in the cloud collide with each other in motion, and the small droplets in the upper part of the cloud fall to the lower part of the cloud, and the water droplets will get bigger and bigger, and when they are so large that the updraft cannot support them, it will rain. ”

Qiao's mother gestured with her hand to the movement of the entire water droplet, and finally made a rainy action, and Qiao Bao was fascinated by it.

"It turns out that this is how it rains, so isn't our water endless?"

Qiao Bao tilted his head curiously, "But the sea water is so salty!" Can you take out the salt in it, and you can cook again, and use the unsalty water to drink? ”

"No, Qiaobao, it should be extracted from the seawater, which can obtain high-concentration seawater, and then dry it into salt.

Now there is reverse osmosis technology, through which seawater is added to the reverse osmosis membrane at a certain pressure, and fresh water can pass through the reverse osmosis membrane to remove high concentrations of seawater.

The desalination rate of this method can reach more than 95 percent, which can be used by humans. ”

Qiao's father explained, "However, this kind of salt and water cannot be eaten directly, and it also requires a complex purification process, which is a big project." ”

"Qiao Bao doesn't understand very well..."

Qiao Bao lowered his head, "But Qiao Bao will read a lot, and he will be able to understand when the time comes!" ”

"That's right, Qiao Bao, this is also a part of the water cycle, let's go to the living area to see what water recycling is."

Qiao's mother pulled Qiao's father to the living area, where Qiao Bao saw the familiar living room, kitchen, and bathroom, and laundry pool.

"Oh-I see!"

Qiao Bao finally clapped his hands happily.