vit
acti ies
8&9
More Water into the Air
(Sessions I and II)
BROWARD COUNTY ELEMENTARY SCIENCE BENCHMARK PLAN
Grade 3—Quarter 1
Activities 8 & 9
SC.A.1.2.2
The student knows that common materials (e.g., water) can be changed from one state to
another by heating and cooling.
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SC.H.1.2.1
The student knows that it is important to keep accurate records and descriptions to provide
information and clues on causes of discrepancies in repeated experiments.
SC.H.1.2.2
The student knows that a successful method to explore the natural world is to observe and
record, and then analyze and communicate the results.
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SC.H.1.2.3
The student knows that to work collaboratively, all team members should be free to reach,
explain, and justify their own individual conclusions.
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SC.H.3.2.2
The student knows that data are collected and interpreted in order to explain an event or
concept.
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ACTIVITY ASSESSMENT OPPORTUNITIES
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The following suggestions are intended to help identify major concepts covered in the activity
that may need extra reinforcement. The goal is to provide opportunities to assess student
progress without creating the need for a separate, formal assessment session (or activity) for
each of the 40 hands-on activities at this grade level.
1. Session I—Activity 8: Ask, Why did you cover the leaf with a plastic bag? (to hold the
water vapor inside the bag and keep it from disappearing into the air) Where did the water
in the bag come from? (It came out of the leaf as water vapor and then condensed into
drops.) Do you think the type of soil you use would make a difference in how much water
evaporated from the soil? (Yes, some types of soil, such as soil with a lot of decaying
leaves in it, may hold water better than other soils.)
2. Session II—Activity 9: Remind students that they used an Activity Sheet to record their
observations and results. Ask, Why is it important to record information when you do a
science experiment? (Recording helps us remember what we saw and did. It makes sure
that we don’t forget measurements. It helps us make sense of our results and figure out
why things happen.)
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3. Use the Activity Sheet(s) to assess student understanding of the major concepts in the
activity.
In addition to the above assessment suggestions, the questions in bold and tasks that
students perform throughout the activity provide opportunities to identify areas that may
require additional review before proceeding further with the activity.
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activities 8 & 9 More Water into the Air
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vit
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8&9 More Water into the Air
OBJECTIVES
The students observe that water evaporates
not only from bodies of water, but also from
soil and plants.
The students
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observe that plants and soil give off water
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infer that water loss occurs through the
leaves of plants
For the class
2
light sources
1
marker, felt-tip*
1
plant, potted*
1 bag soil, potting
1 roll tape, masking
water, tap*
Delta Science Reader Water Cycle
*provided by the teacher
SCHEDULE
Session I—Activity 8 About 30 minutes
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VOCABULARY
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MATERIALS
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For each student
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Activity Sheet 8
1 pr
safety goggles*
Session I—Activity 8
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Session II—Activity 9 About 30 minutes,
1–2 days after Session I
transpiration
1
Make a copy of Activity Sheet 8 for each
student.
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You will need to obtain a potted plant.
Allow the soil to dry out.
3
Identify either trees with low branches or
large-leafed bushes on or near the school
grounds. If none are available, obtain
additional potted plants to use in this
activity.
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Fill each tumbler half-full with potting soil.
Fill each 1-oz plastic cup with water.
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Check to be sure that the two light
sources are in a place where there will be
room for the students’ soil set-ups.
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Each team of two will need one plastic
bag and tie, a sheet of white paper, a
small plastic cup filled with water, and a
tumbler half-full of potting soil. Each team
will also need a strip of masking tape.
For each team of two
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1
1 sht
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PREPARATION
bag, plastic, with tie
cup, plastic, 1-oz
paper, white*
tumbler, plain
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Session II—Activity 9
Each student will need his or her copy of
Activity Sheet 8.
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BACKGROUND INFORMATION
Activity Sheet 8
Not all of the water in soil is absorbed by
the soil, and not all of it travels downward
to remain stored in the rock below. Some of
the water evaporates into the air. Some of
the water is pulled in by plants, which
absorb water through tiny hairs on their
roots. The water travels upward through
cells that form long tubes extending from
the roots, through the stems, all the way to
the leaves.
In the leaves of green plants, the water is
used for photosynthesis. Photosynthesis is
the process by which, in the presence of
light, water and carbon dioxide combine to
form oxygen and sugar, which the plant
uses for food.
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Transpiration is the evaporation of water,
primarily through the stomata, into the air.
Plants in temperate climates transpire
99 percent of the water taken in by the
roots. About 1 percent of the water is used
in the cells of the plant for photosynthesis
and other processes.
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The stomata contain guard cells, which
function as gates to open and close the
pores. Generally, the stomata are open
during the day and closed at night. This
way, the plant takes in carbon dioxide for
photosynthesis during daylight hours.
However, transpiration is greater during the
day than at night, due to the heat of the
sun. When a plant begins to dry out, the
stomata will close, even during the day.
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activities 8 & 9 More Water into the Air
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The leaves of plants contain small openings,
or pores, called stomata (singular, stoma).
The stomata function in allowing the
exchange of carbon dioxide and oxygen.
However, plants also lose water through
these openings.
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Guiding the Activity
Additional Information
Session I—Activity 8
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Show the students the potted plant. Ask,
What do you notice about the soil?
It is dry.
Pour a little water onto the soil. Ask, What
happens to this water? Does the water stay
in the soil? Does it go into the plant?
Remind the students that plants contain
water. Ask the students, How do plants
obtain water?
Accept all reasonable ideas.
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Tell the students that they will perform two
activities to investigate these questions. Give
each student a copy of Activity Sheet 8. Give
each team of two a plastic bag and tie, a
sheet of white paper, a small plastic cup of
water, and a tumbler of potting soil.
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Have students moisten the soil by adding the
water from the plastic cup. If the soil is not
fully moistened, refill the plastic cup and add
more water to the soil (see Figure 8-1).
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Students may know that they take up water
from the soil through their roots.
Ask, What do you think happens to the
water once it is in the plant?
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Students should say that it seeps into the
soil. They may suggest that some seeps all
the way through the soil. They may also
realize that some water is taken into the
plant.
The soil should be well moistened, but does
not have to be soaking wet. The amount of
water the students need to add will depend
on the moisture level of the soil at the start.
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Tell the students to write their names on the
piece of white paper. Carefully dump the soil
onto the paper and spread it out.
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Have the students observe the soil, and
record their observations on the activity
sheet. Then refer them to the light sources
and show the students where to leave their
soil samples overnight.
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Figure 8-1. Adding water to the soil
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Guiding the Activity
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Give each team a strip of masking tape and
instruct them to write their names on the
tape and attach it to their plastic bag. Make
the marker available for this purpose. Tell the
students they will now go outside to set up
the second experiment. Explain that they will
attempt to collect water from the leaves of
plants.
Additional Information
If you are using house plants, assign groups
to each plant.
Outside, demonstrate how to secure a plastic
bag over a single leaf. Emphasize that the
leaves must remain attached to the plant
during the collection process (see Figure 8-2).
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Ask, How tightly should you twist the wire?
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Have the students place their bags on the
leaves.
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Figure 8-2. Collecting water from leaves
The wire ties should be twisted just enough
to prevent air and water from entering the
bag, but not so tight as to damage the plant.
Once inside, collect each student’s copy
of Activity Sheet 8 for use in Session II,
Activity 9.
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Give each student his or her copy of the
activity sheet. Have the students retrieve
their soil samples, and instruct them to
complete step 2 on the activity sheet.
Ask the students, What happened to the soil
when it was left out?
It dried out.
Ask, Based on what you already know, what
do you think happened?
Students should infer that the water in the
soil evaporated.
activities 8 & 9 More Water into the Air
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Session II—Activity 9
Guiding the Activity
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Additional Information
Ask, Why were the soil samples placed
under a lamp?
The heat from the lamp aided the process of
evaporation.
Ask, Once the water evaporated, what
happened to it?
It entered the air as water vapor.
Take the students outside to observe the
plastic bags. Ask, What is in the bag?
Water droplets coat the inside of the bag.
Ask, How did water get into the bag?
Lead students to realize that the water came
from the soil, was taken up by the plant
through its roots, and evaporated into the air
in the bag.
Have the students carefully remove the bags
from the leaves. Return to the classroom with
the students.
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Ask the students, From which part of the
plant do you think the water evaporated?
The students should infer that because the
leaf was enclosed in the bag, the water came
from the leaf.
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Explain that plants lose through their leaves
most of the water that is taken up by the
roots. Write the word transpiration on the
board. Explain that the leaves of a plant
contain tiny openings, or pores. The water in
the plant passes through these tiny openings,
and evaporates into the air. This process is
called transpiration.
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Tell the students to complete their activity
sheets.
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Ask the students, If water is constantly
transpiring from leaves, why don’t you see
water falling from leaves all the time?
Again show the students the potted plant and
pour a small amount of water onto the soil.
Ask, Based on what you observed in this
activity, what can you now say about what
happens to this water?
As soon as the water evaporates as water
vapor, it is carried away by the outside air.
As the students tell what happens to the
water, list the items on the board. They
should say that the water enters the soil, and
some of the water is taken up by the plant.
Most of that water evaporates into the air
through the plant’s leaves. The water in the
soil also evaporates directly into the air.
As appropriate, read or review pages 8–9 of
the Delta Science Reader Water Cycle.
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SCIENCE JOURNALS
Repeat the activity using two house plants,
one that has been watered and one that has
not been watered for several days. Have the
students predict which will give off more
water. (the one that was watered) Allow time
for water to collect in the bags. Ask the
students why the plant that was watered
gave off more water. (The plant that was not
watered had no source of water, so no water
was available for transpiration.)
Have students place their completed
activity sheets in their science journals.
CLEANUP
Assessment Opportunity
This Reinforcement also may be used
as an ongoing assessment of students’
understanding of science concepts
and skills.
Tell the students to return as much of the
soil as possible to its original bag for reuse.
Have them remove the tape from their
plastic bags and hang the bags to dry.
Rinse and air dry the tumblers and plastic
cups. Have students return the bag of
potting soil to the kit, along with the
masking tape, wire ties, and light sources.
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activities 8 & 9 More Water into the Air
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REINFORCEMENT
Connections
Science Extension
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Make sure students understand that
during transpiration, plant leaves release
water vapor, not liquid water, and that the
water droplets they observed in the bags
did not come directly from the plant leaves
but formed (condensed) from the water
vapor they released. To demonstrate this,
have students seal a small, shallow dish
filled with water in a plastic bag and place
it and an identical water-filled but
uncovered dish in direct sunlight for
several hours. Students will see that water
evaporates from both dishes. With the
enclosed dish, water vapor condenses
again to form liquid water droplets on the
inside of the bag. With the uncovered dish,
the water vapor simply dissipates into the
surrounding air—just as it does with
transpiration from plant leaves.
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Set up several microscopes in the classroom
so students can observe prepared slides of
stomata. If microscopes are not available,
provide color photographs or projector slides
for students to examine. Ask students to
choose one example and draw what they see.
Encourage them to make their drawings as
accurate as they can and to color them so the
different parts can be clearly seen. Then have
students find scientific illustrations of
stomata in biology textbooks and other
sources and compare the illustrations with
their own drawings. (Also see Science and
Careers below.)
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Science and Careers
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The following activity will enable students to
observe the movement of water up a plant
stem. Have each team add several drops of
different food coloring to each of three
glasses filled about halfway with water. Give
each team two celery stalks with leaves. Tell
students to snip the ends off both stalks
and put one stalk into one of the glasses.
Have them split the other stalk up to the
beginning of the leaves and then put one
split end in the second glass and the other
in the third glass. Students should leave the
glasses in a warm place for a few hours and
check the stalks periodically. (The colored
water will gradually move up the stalks and
into the leaves. With the split stalk, half the
leaves will be colored one color and half the
other color.) Let students remove the stalks
from the glasses, wipe them dry with a
paper towel, and examine the cut ends with
a magnifier. They should notice colored dots
around the edge of each stalk. Explain that
these are the ends of tubes that lead from
the plant’s roots up to its leaves. Students
might like to use this method at home to
dye white carnations or other fresh flowers.
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Science and the Arts
As a follow-up to Science and the Arts
above, explain that some artists specialize
in doing scientific illustrations for books and
magazines. Invite a medical illustrator or
scientific illustrator to visit the class and
describe his or her work. Encourage the visitor
to bring examples of illustrations he or she
has created and to describe the research that
must be done in order to produce accurate
pictures. Students who are particularly
interested in art might like to ask the visitor
questions about the education and training
required for this field.
Science and Language Arts
Have students use a dictionary to find out the
derivation of the term transpiration. (from the
Latin trans, meaning “across” or “through,”
and spirare, “to breathe”) Also ask students
to list as many other words as they can think
of that begin with the prefix trans- and to
define each one in their own words. Let
students share their lists and definitions.
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activities 8 & 9 More Water into the Air
© Delta Education. Photocopying and distribution prohibited.
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Activity Sheet 8
Name
More Water into the Air
Permission granted to purchaser to photocopy for classroom use.
Session I—Activity 8
1. Carefully dump the soil onto the paper and spread it out.
Observe the soil. Record your description in the table.
Soil at
beginning
Soil at
end
Session II—Activity 9
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2. Observe the soil again. Record your description in the table.
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What happened to the water in the soil?
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© Delta Education
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3. Observe your plastic bag. Answer questions a and b.
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a. What was in the bag?
b. Where did they come from?
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