BACKGROUND:
Water is essential in animal and plant
nutrition. It is used in science and industry in making many products.
Waterways are used to transport materials and dispose of waste.
Water is also a cooling agent, a cleansing medium, and entertainment mechanism.
Water most probably originated on this planet
as gases emitted from volcanoes. The Earth's atmosphere
captured this water and has continuously recycled it throughout time, in
what is called the water cycle. Water evaporates and forms clouds.
The clouds provide rain and snow, which is collected in rivers, lakes,
underground reservoirs, and oceans that are the source for further evaporation.
The water cycle is a major driving force on
our planet. Water is in constant motion, evaporating into the atmosphere
to from oceans, lakes, rivers, and streams. When the atmosphere can
no longer support the moisture within the clouds, we experience rain, snow,
hail, or sleet. Water is returned to the system through drainage,
which results from the melting of snow that has accumulated during the
winter months. This water flows on the surface of the Earth and percolates
through the Earth as groundwater. Water is not actually consumed but is
continuously recycled.
PROCEDURE:
- Water is a liquid that is
very important to all life. Emphasize that every clear liquids may
not be water. Demonstrate to students by using other
liquids that are not water. Ask them is they can drink bleach or
ammonia? Can you cook with hydrogen peroxide? Remind students to always make sure they are drinking
water and not other clear liquids.
- Use alcohol to stress that water is odorless and
tasteless. .Rub a little alcohol on the inside of the
wrist of your students. On the other arm use water. Ask students
what the difference is between the two clear liquids. Alcohol seems
cooler because it evaporates quickly. Water does not evaporate as
quickly. You may want to use a cotton swap to make the process more
dramatic.
- Water is important in the water cycle. Use
the song Drippy the Hippie to help students learn the words precipitation,
evaporation, and condensation. Using the worksheet, discuss with children how water becomes clouds by
evaporation. Water can then be recycled in the process.