How and Why Does Water Climb?
Did you ever wonder about how water gets up into the stem
and leaves of a plant? Have you ever noticed how a paper
towel or clothing soaks up water? Did you know that water can
defy gravity by pulling itself upward? This special event is
called capillary action. How far do you think water will climb?
Let’s test different kinds of paper to watch it moving and to find
out which material will allow water to climb the highest. We will
use colored water, so we can observe it more closely, and
record our observations on a recording sheet. Don’t forget to
measure how far the water travels each time.
How and Why Does Water Climb?
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How and Why Does Water Climb?
Suggested Grade Span
K–2
Task
Did you ever wonder about how water gets up into the stem and leaves of a plant? Have you
ever noticed how a paper towel or clothing soaks up water? Did you know that water can defy
gravity by pulling itself upward? This special event is called capillary action. How far do you
think water will climb? Let’s test different kinds of paper to watch it moving and to find out which
material will allow water to climb the highest. We will use colored water, so we can observe it
more closely, and record our observations on a recording sheet. Don’t forget to measure how
far the water travels each time.
Big Ideas and Unifying Concepts
Cause and effect
Models
Systems
Physical Science Concepts
Motion and forces
Properties of matter
Mathematics Concepts
Data collection, organization and analysis
Measurement
Number properties, numeration and number sense
Time Required for the Task
Approximately 45–60 minutes (over 2 days):
Day 1: Exploration of capillary action
Day 2: Investigation and recording of observations and results
How and Why Does Water Climb?
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Context
This investigation is an extension of a previous water activity (and larger unit of study) that
involved the observation of surface tension. (See "What Do We Know About Water?") Students
use their prior knowledge from that and other activities to extend their conceptual understanding
for this inquiry.
What the Task Accomplishes
This task combines the skills needed for measuring, recording, and organizing data to make
comparisons with observation skills. The more students practice these skills, the greater
success and confidence they will experience. This has promoted a positive attitude toward
science in my classroom and in the homes of many of my students, where investigations often
continue.
How the Student Will Investigate
On the first day, after observing that students were having difficulty controlling the variables such as folding the paper, adding the water, and observing the absorption (timing and
measuring) - I moved from group to group guiding them in developing techniques for using the
materials consistently. As a class, we decided to fold the paper the “long way” and to use the
classroom clock’s red second hand to time the samples of paper in the colored water, each for
one minute. We also talked about putting the same amount of water on the paper to make it a
“fair test.”
On the second day, groups of students were given a recording sheet and asked to test five
types of paper and to record results. Each type of paper was to be labeled. The height the
water moved up the paper was measured and recorded after one minute, and a drawing was
made to show the results. Although each student completed an individual recording sheet, jobs
were assigned and rotated for each sample: (1) timer, (2) measurer, (3) label checker and (4)
drawing checker. (These jobs could also remain the same throughout the testing. An easy way
to facilitate task assignments is to give each student in the group a number (1 - 4) and
designate job tasks for each number.)
Interdisciplinary Links and Extensions
Science
Other related capillary action activities could include timing water races on different types of
strings, observing celery stalks in colored water, comparing absorption rates for a plant with and
without root hairs attached to the main root, and/or product testing of different brands of paper
towels or sponges. Cross sections of plant stems could be examined to see the path the water
takes to the leaves.
Students could discuss why blood vessels are called capillaries and how blood moving though
the body is like water moving though plants or soils.
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Social Studies
Learning about water systems designed by humans, for purposes such as irrigation and
filtration, artesian wells or aqueducts, might provide interesting comparisons to natural systems
and how gravity plays a part.
Language Arts
Some of the children’s literature I used for this unit were: Let’s Look at Rain, by Jacqueline
Dineen; Water, by Webb & Fairclough; The Magic School Bus Wet All Over and A River Ran
Wild, by Lynn Cherry. These books illustrated the water cycle, the importance of rain for plants
and different habitats, the history of a Native American Indian culture on a river, and gravity
experiments with water.
Movement/Music
My students enjoy water songs, rounds and raps, using such songs as“The Dirty Water Blues”
and “Evergreen Everblue.”
Mathematics
Throughout our unit on water, I asked my students to keep logs (counting and measuring)
tracking the use of water at home and in school. We include minutes in the shower, numbers of
flushes and glasses of water consumed to talk about water conservation strategies. We also
create original story problems to solve. (If five people are in the family and each person drinks
two glasses of water. . . or, If a large dog drinks three gallons of water a day. . .) Students can
research, graph and compare how much water different animals require daily.
Teaching Tips and Guiding Questions
I have found that my students are much more successful when I allow for free exploration in
cooperative groups at least one day before I ask them to record data for any given inquiry. This
approach also encourages them to draw on their prior knowledge to formulate predictions and
challenge misconceptions. For students who have not had many rich, multisensory
experiences, this also gives them opportunities to build a solid base of conceptual
understanding. I try to promote “thinking out loud” by asking questions like:
• How do you think we should fold the paper? Time the results? How can we be sure that
each test uses the same amount of water?
• What differences (texture, the weave, feel, etc.) do you see in the papers?
• Did the colored water travel at the same or at different rates?
• Can you demonstrate to me how you measured your paper?
• Which paper would be best for cleaning up spills? Why do you say so?
• Did any of the papers do something you did not expect it to do?
• Why do you think this paper (coffee filter, wax paper, paper towel, etc.) is the kind of paper
used for this specific purpose?
• Did you notice anything about water that reminds you of something we have already done
with water investigations?
• Why do you think the roots of plants have different shapes, sizes and textures?
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Concepts to be Assessed
(Unifying concepts/big ideas and science concepts to be assessed using the Exemplars
Science Rubric under the criterion: Science Concepts and Related Content)
Physical Science – Properties of Matter: Students explore, observe and describe physical
properties and characteristics of water and liquids (capillary action - ability to climb up a surface
against the pull of gravity; absorption - water molecules “sticking” to other substances; cohesion
- water molecules “sticking” to each other).
Scientific Method: Students observe and explain reactions when variables are controlled and
describe cause-effect relationships with some justification, using data and prior knowledge
(cause and effect). Students see that how a model works after changes are made to it may
suggest how the real thing would work if the same thing were done to it (models).
Mathematics: Students use timing, counting and measuring to describe events, answer
questions and provide evidence for scientific explanations.
Skills to be Developed
(Science process skills to be assessed using the Exemplars Science Rubric under the criteria:
Scientific Procedures and Reasoning Strategies, and Scientific Communication Using Data)
Scientific Method: Observing, predicting, hypothesizing, collecting and recording data,
manipulating tools, controlling variables, drawing conclusions, communicating findings and
raising new questions.
Other Science Stamdards and Concepts Addressed
Scientific Method: Students describe, predict, investigate and explain phenomena. Students
control variables.
Scientific Theory: Students look for evidence that explains why things happen and modify
explanations when new observations are made.
Physical Science – Properties of Matter: Students observe, describe and sort objects and
materials according to observations of similarities and differences of physical properties.
Physical Science – Motion and Forces: Students can explain that everything on or near the
earth that is pulled toward the earth’s center by gravitational force.
Mathematics: Students use number sense, counting, and grouping numbers; understand and
apply concepts of more than/less than; and use numerical data and (precise) measurements in
describing events, answering questions, providing evidence for scientific explanations and
challenging misconceptions.
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Suggested Materials
For paper samples, I provided store-brand paper towels, wax paper, coffee filters, brown
(school) paper towels, white drawing paper, newsprint, computer paper and colored
construction paper. Students selected five to test and were encouraged to try others they could
find in the room. (Some tried playing cards, old bookmarkers and different-colored paper.) Each
group placed the cups of colored water in a clear plastic tub. I added green food coloring to the
water ahead of time. Magnifying lenses and math manipulatives were available as needed for
examining and measuring. Each student had a recording sheet to complete.
Possible Solutions
Student drawings, recordings and explanations should demonstrate understanding of the
concepts of cohesion, absorption and capillary action, although I did not expect students to use
the scientific terms. A minimum of five papers should be recorded, labeled, drawn and
measured. Students should measure accurately to the nearest half inch (of object used) and
identify that papers such as paper towels and coffee filters absorb more water than wax paper,
etc. Differing rates of absorption should also be noted, and some observations about the
differing textures or weaves of the papers might be described.
Task-Specific Assessment Notes
Novice
This student’s solution is complete but lacking in necessary details. The drawings are not
accurate (for example, there should be water drops running off the wax paper, the tip of the
coffee filter should be wet, and the white drawing paper and brown paper look exactly the same
but have different measurements). There is some evidence of understanding how to use tools
and record data.
Apprentice
This student’s solution is labeled and more than five items are tested. The measurement for
wax paper is missing, and some of the drawings are unclear or inconsistent with measurements
(e.g., the cup says “0” for the measure, yet the drawing shows water absorption). There is
evidence that the student collected data, but additional observations are noted for only three
papers (e.g., “slid of” for wax paper). The student did not clearly identify which paper allowed
the water to climb the highest.
Practitioner
This student’s solutions are complete. All data are recorded accurately; labels are clear and
drawings are vivid, showing how water beads up on the wax paper. The student has included
the rate of capillary action for the one minute that was observed (fast/slow notations). The
student tests additional items (playing card, sorting cup, etc.), as well. Conclusions are drawn
from data collected – evidence of conceptual understanding and reasoning.
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Expert
This student’s solutions are complete and detailed. The drawings are clearly labeled, and
additional detailed observations are noted for most of the items tested. Conclusions are drawn
from data collected and include a comparison of the two fastest materials – evidence of
conceptual understanding and reasoning.
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Novice
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Apprentice
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Apprentice
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Practitioner
How and Why Does Water Climb?
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Practitioner
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Expert
How and Why Does Water Climb?
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Expert
How and Why Does Water Climb?
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