Mary Allen
There is water in the rain, in streams and rivers, in lakes and seas, but also at every tap. Pure water is transparent and has no color. It has no taste and no smell. In chemistry, water is a compound of oxygen and hydrogen.
We know the water in three forms: when it is normally warm, water is liquid. Below 0 degrees Celsius, it solidifies and freezes to form ice. At 100 degrees Celsius, on the other hand, water begins to boil: bubbles of water vapor form in the water and rise. Water vapor is invisible or transparent. It can be found in every room or outdoors because the air is never completely dry.
We call the white fumes above the saucepan steam. But that is something else again: They are tiny water droplets like in fog or in clouds. The team has already turned back into liquid water here. We say: it liquefied or it condensed.
Water gives buoyancy: a piece of wood, an apple, and many other things do not submerge, but rather float on the water. Even an empty glass bottle with a lid floats, although glass is heavier than water. This is because it displaces a lot of water but only contains air itself. The ships take advantage of this. The steel they are made of is heavier than water. However, it still swims through the cavities inside the ship.
In nature, water moves in a cycle known as the water cycle: rain falls from the clouds and seeps into the ground. A small stream comes to light in the source. It joins with others into a great river, perhaps flowing through a lake and finally into the sea. There the sun sucks up the water as steam and forms new clouds. The cycle begins again. Humans take advantage of this cycle by generating electricity from hydropower.
In clouds, rain, streams, lakes, and rivers, the water does not contain salt. It’s fresh water. If it’s clean, it’s potable. Salt accumulates in the seas. Fresh water mixes with salt water in the estuaries. The resulting water is called brackish water.