The freezing point of water is 32 degrees Fahrenheit. If the temperature should be below freezing when condensation takes place on the grass or on the ground, dew will not form. Instead of growing into dewdrops, the water molecules become tiny crystals of ice. A mass of ice crystals that form in this way is known as frost. It is important to remember that frost is not dew which has frozen. The frost particles form directly from the molecular state when the temperature is sub-freezing. Dew formation and frost formation are essentially the same. The only difference between them is the temperature at which each takes place.
Rain and Snow. You will remember that the particles which make up a cloud are very tiny. In fact, the water droplets are so small they float about without falling to the ground. At times, however, these water particles tend to get larger. This may happen when several droplets join with others over and over again. Or, growth may occur if the process of condensation continues to take place. In either event, the original droplet may grow a million times its size into a full sized drip. Of course, the air can no longer keep such large drips afloat and precipitation takes place in the form of rain.
1. Precipitation can be controlled to transform deserts into productive lands.
2. Rain, snow, sleet and hail are different forms of precipitation.
3. The passage is mainly about precipitation processes and forms of precipitation.
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