Water is the most common liquid on Earth. It covers about 71.4% of the Earth. Pure water has no smell, taste, or color. Lakes, oceans, and rivers are made of water. Rain is water that falls from clouds in the sky. If water gets very cold (below 0 degrees Celsius), it freezes and becomes ice. Frozen rain is hail. Snow is formed from water vapour, not rain. If water gets very hot (above 100 degrees Celsius), it boils and becomes steam. Water is a fluid. Water is the only chemical substance on earth that exists naturally in three states. People know of over 40 anomalies about water. Unlike most other liquids such as alcohol or oil, when water freezes, it expands by about 9%.
Rain is when water falls from clouds in droplets that are bigger than 0.5 mm. Rain is a kind of precipitation. Precipitation is any kind of water that falls from clouds in the sky, like rain, hail, sleet and snow. It is measured by a rain gauge. Rain is part of the water cycle.
A rainstorm is a sudden heavy fall of rain. It may cause floods in valleys. Heavy rain for a long time may make rivers overflowing. Also, landslides may happen.
When the Sun heats the Earth's surface, the ground heats the air above it. Convection makes the air rise and cool. When it cools to the dew point, clouds form and rain follows. This type of rainfall often causes summer showers and thunderstorms.
The dew point is the temperature where water vapour condenses into liquid water.
All air holds different amounts of water vapour. The dew point shows the amount of humidity in the air. The higher the dew point is, the higher the level of humidity in the air at a given temperature. The dew point of humid air will be higher than the dew point of dry air.
Condensation of water vapour starts when the temperature of air is lowered to its dew point and beyond. The dew point, like other measures of humidity, can be found from measurement taken by a hygrometer.
Drizzle is the name given to light rain. The drop size of drizzle is smaller than that of rain, about 0.5 mm (millimeters) in diameter.
A rain gauge is an instrument used by meteorologists and hydrologists to measure precipitation in a certain amount of time.
What water is made of
Water is a molecule made of 2 hydrogen atoms and 1 oxygen atom. Its chemical formula is H2O. Water has a surface tension, so a little water can make drops on a surface, rather than always spreading out to wet the surface. Water can also be called 'aqua', which is the Roman word for water.
Ice. Solid water form and all about it
Ice is the common name for frozen water. Other liquids, such as ammonia or methane or milk could be called ice when they freeze but the name would always be 'milk ice', for instance, instead of just 'ice'. For explain, Ice is commonly made in a home refrigerator or freezer. If water is put in a freezer and left for a while, the water gets very cold and will freeze solid, creating ice. Water can be placed into a copper (or other metal) container to cause it freeze into ice faster. Metals are good conductors of heat, so water can freeze faster than in a plastic ice tray.
How ice is formed
Unlike other liquids, water expands as it freezes to become ice; so ice floats on water because ice has less density than water. This is very unusual - just about every other liquid gets more dense as it cools; water ice, however, is an important exception. Liquid water expands by about 9% as it becomes ice - it takes up more space. If water in pipes freezes it can burst the pipe. Water in glass bottles can explode in the freezer if people leave it there long enough to freeze. Water freezing in rock cracks can expand enough to split hard rocks apart; this is an important geological weathering process that can wear down mountains and make rock into soil.
When materials are cooled their molecules vibrate less and compact together. When most materials reach a temperature called the freezing point, the molecules form a crystalline solid. Only Helium will not freeze; all other substances will freeze if cold enough, but fluids like cooking oil, anti-freeze, petrol (gasoline), nitrogen, etc. freeze at temperatures that most people don't experience.