Earth’s Water Cycle for
Secondary Students
Global Precipitation
Measurement Mission
Developed by the GPM
Education and Public
Outreach Team
NASA Goddard Space
Flight Center
Revised Sept. 2018
Guiding Questions
• The Big Picture: Why is it important to measure rain and
snow around the globe?
• Earth’s Water: How much of Earth’s water is freshwater?
• Freshwater versus Saltwater: Which of these do we need
for our survival?
• The Water Cycle: How does water move through the
“water cycle?
• Precipitation: Where do rain and snow come from? Are
these made up of freshwater or saltwater?
• GPM: How will the GPM mission measure precipitation all
over the world?
• NASA and Earth Science: NASA is helping us learn about
our home planet!
2
ENGAGE
Solid? Liquid? Gas?
Freshwater vs. Saltwater
How much of Earth’s water is freshwater?
We will make a model of Earth’s freshwater.
1.Take the plastic cup, and imagine that the cup is a
model of Earth’s surface.
2.Fill up ~ 75% with water. This represents how much of
Earth’s surface is covered with water.
3.Take out one eye-dropper of water, and place it in the
small medicine cup. This represents how much of
Earth’s water is freshwater- ~ 2.5%
4.Take one drop of this water- this represents how
much freshwater is easily accessible to us!
Saltwater versus Freshwater
Water on Earth
Credit: Earth Forum, Houston Museum of Natural Science
“Show Me the Water” video
Show Me the Water
Link to GPM movie
Earth’s Water Cycle
Earth’s Water Cycle
Measuring Rainfall
• Most of the water we use everyday comes from
precipitation.
• It is important to measure how much precipitation is
falling all over the world.
• We can measure precipitation using rain gauges,
radar, and even from space using satellites!
“Getting the Big Picture”
The Global Precipitation Measurement mission
Last Week’s Precipitation
What can we do with the data?
Flooding
Landslides
Extreme Events
Freshwater Availability
Agriculture/Famine Early Warning
Land surface and climate modeling
The rain and snow data
gathered from the TRMM
and GPM missions already
provide and will extend our
capabilities to study a wide
range of applications for
scientific research and
societal benefit.
World Health
Questions?
• Do you have any questions about Earth’s water cycle
and how we are learning more about it?