THE
HYDROLOGIC
CYCLE
DISCUSSION QUESTIONS:
1. Why is the hydrologic cycle an important process for Earth?
2. Is there a beginning or end to the hydrologic cycle? Explain.
INTRODUCTION:
When one looks around at the world and
sees all the water on the earth and
watches all the rain that falls from the sky,
it is easy to believe that there is a constant
supply of water for us. However, this isn’t
the case. The earth has only a limited
amount of water, and it is recycled over
and over again in a process called the
water cycle, or hydrologic cycle. The water
that is present on the earth today has
been here for millions of years. It goes
through processes of evaporation,
precipitation, and percolation. Sometimes
the water will be present in a liquid state,
sometimes solid, and sometimes gaseous,
as molecules rise from the oceans up to
the clouds.
DISCUSSION: HOW THE CYCLE WORKS?
• The hydrologic cycle — also
known as the water cycle
— is the continuous
exchange of water
between Earth's surface
and the atmosphere. As the
planet's natural mechanism
for transporting and
recycling water, the
hydrologic cycle is critical
for maintaining conditions
on Earth. There are five
basic steps within the
water cycle: condensation,
precipitation, infiltration,
runoff, and
evapotranspiration.
http://earthguide.ucsd.edu/earthguide/diagram
s/watercycle/
STUDENT ACTIVITY:
In small groups, using grade 9 Geographic regions, answer these
questions:
• How does the water cycle impact settlement
locations?
• How does the water cycle impact vegetation?
• How does the water cycle impact on the development
and extraction of resources?
• Account for and explain the precipitation in your
region?
• How does settlement impact the water cycle?