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Facts About Water on Earth
The water on Earth has been here since the beginning
of time. The Earth is a closed system containing all the water we will ever
have. The recycling process of the water cycle moves on geologic time, which
means it can take thousands of years.
- Less than 1 percent of all the water on Earth is fresh water that
we can actually use. We use this small amount of water for drinking,
industry and other purposes.
- Almost 80 percent of the Earth's surface is covered with water.
- Salt water covers 97 percent of our planet. We cannot drink this water.
It's very difficult and very expensive to remove the salt.
- Two percent of the water on Earth is glacier ice at the North and
South Poles. It is frozen and too far away from where people live to
be usable.
- Earth's waters are constantly in motion in a process known as the
hydrologic cycle.
- At any given time, only 5 gallons of every 100,000 gallons of water
is in motion.
- Throughout time, the same water has been transferred from the oceans
into the Earth's atmosphere and dropped on land again where it inevitably
ends up back in the seas. That means the water we use today is the same
water that was here when dinosaurs roamed the land.
- The hydrologic cycle has no beginning and no end. No water is gained
or lost in the cycle, but the water available to users can fluctuate
due to cycles in the weather and changes in water quality.
- Evaporation occurs when water molecules absorb energy from the sun
and break away from other water molecules to enter the atmosphere as
vapor.
- When the temperature drops, water vapor may collect in liquid droplets,
which can be seen in the form of fog, mist or dew. This is known as
condensation.
- Without water, the Earth would look like the moon.
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