Weather
Charlene Clark Fulton Elementary School
5300 S. Hermitage Avenue
Chicago IL 60609
(773) 535-9000
Objectives:
This lesson is designed for Grade 5 science.
Each student will be able to:
Distinguish among evaporation, condensation, and precipitation phases of
the water cycle.
Materials Needed:
Activity 1. two equal pieces of sponge, string, wire coat hanger, hair dryer,
ring stand, tap water in container to wet sponge
Activity 2. hot plate, pan of water with lid, mirror
Activity 3. chalk dust, hammer, nail, 2 lids (one that fits the jar, and one
that's extra large for the jar), medium-sized jelly or pickle jar,
very hot tap water, timer, 2 ice cubes
Activity 4. container filled with sod and saturated with water, plastic wrap,
chicken wire, heat lamp (optional)
Strategy:
Introduction:
Ask students to think about the word "cycle". Bring out the concept that
a cycle is round. Then introduce the subject of the water cycle, which will
be developed further, when an understanding of evaporation, condensation, and
precipitation, are understood.
1. Evaporation
Begin by asking questions about evaporation. Allow students to give
examples of evaporation and list them on paper or the board. Demonstrate
evaporation with Activity 1. Tie equal lengths of string around equal pieces of
sponge. Wet each piece of sponge with equal amounts of water. Attach the free
end of the string to a coat hanger. Balance the hook of a coat hanger on a ring
stand. Use a hair dryer to evaporate the water from one sponge piece. When one
sponge is dry (water is evaporated) the coat hanger should balance unevenly
showing that water has weight and has evaporated from the sponge that is now
dry. Develop a definition for evaporation, which is water that changes from a
liquid to a gas called water vapor which cannot be seen. Rising warm air
carries the invisible moisture high up in the sky.
2. Condensation
The invisible water vapor gathers together as it cools and condenses to
form a cloud. The droplets stick together with the help of dust particles in
the air. Lead students to discover that evaporation and condensation are
opposite occurances. Discuss various ways water vapor condenses. With Activity
2, show condensation of water by heating a pan of water over a hot plate and
holding a mirror or jar lid over the steam until the vapor condenses.
3. Precipitation
Eventually the collection of water droplets that form a cloud gather and
get larger and heavier. When they get too large and too heavy to be held up in
the air, they fall to the ground as a form of precipitation. Precipitation is
water in any form falling from the clouds. It includes rain, drizzle, hail,
sleet, and snow. Warmer air causes droplets to fall as rain. As the air turns
colder, the water freezes and precipitation turns to sleet or snow. Hail is
freezing rain that is bounced up and down by wind currents adding layers of ice
to form hailstones. The inside of hailstones is similar to the rings of a cut
tree trunk. With Activity 3, show a demonstration for precipitation. Fill a
jar 100% with hot tap water. Cover it tightly with the lid and let it stand 2
minutes. Remove the lid, pour out 90% of the water. Place the large lid, with
holes punctured in it, on top of the jar. Cover the lid with ice cubes and let
it stand 3 minutes. Remove the lid and cubes. Sprinkle chalk dust into the
jar. Cover the jar with the tightly fitting lid. After 2 minutes observe the
inside of the jar. A cloud has formed along with precipitation falling. By
heating and cooling the water in the jar, it caused droplets of water to form.
This demonstration shows that clouds are collections of tiny water droplets that
form around particles of dust, dirt or salt. Without tiny particles in the air,
we would not have clouds - or rain.
What happens? Water is constantly recycled over and over again, since the
beginning of time. People and animals and plants use the same water over and
over again. Water in the ground, in lakes, rivers, oceans, puddles, etc. is
used, evaporated in the air, condenses and falls as precipitation and is used
over and over again and again. At least 3/4 of our planet is water.
Everything we see and use is mainly made up of water. Even our bodies are
mostly made up of water.
Show a demonstration of the water cycle with Activity 4. Fill an aluminum
pie tin with sod and saturate it with water. Make a tent cover of chicken wire
covered with the plastic wrap. Place it in the sunlight or use heat lamp.
After a time water droplets should appear. Similar to a terrarium.
Performance Assessment:
Ongoing assessment throughout activities based on the student's
participation and responses.
References:
Bramwell, Martyn. Weather. New York: Franklin Watts, 1987.
Purvis, George and Anne. Weather and Climate. New York: The Bookwright
Press, 1984.
VanCleave, Janice. Chemistry for Every Kid. New York: John Wiley and Sons,
Inc., 1989.
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