Evaporation
Exploration
from
Y
ou’re geared up and ready to play. Wait!
What are you wearing? Fabrics like
cotton can soak up sweat and water, and
they dry slowly. So as you sweat, cotton
clothes can become wet and sticky, even
heavy—they hold on to the water they soak
up. The new high-tech fabrics in modern
sports clothing are different. They have the
ability to pull moisture away from the skin
and carry it to the outer surface of the clothing, where it can evaporate more easily and
cool you off. In the following activity, you will
compare the rate of evaporation of water
from cotton and a paper towel, which will
act like a high-tech fabric.
Be sure to follow Milli’s Safety
Tips and do this activity with
an adult! Do not eat or drink any of the materials
used in this activity.
SAFETY!
Materials
Permanent
marking pen
Small cup
Hot tap water
Roomtemperature
water
4 zip-closing
plastic bags,
quart size
2 droppers
2 brown paper
towels
2 pieces of
3” x 3” cotton
fabric swatches
Celebrating Chemistry
Procedure
1.Use a marking pen to label the cup “Water”.
2.Use the marking pen to label 2 zip-closing bags with
“Room Temp”. Label the other 2 bags with “Hot
Water”.
3.Add about 1 cup of room-temperature water to each
of the 2 zip-closing plastic bags labeled “Room
Temp”. Get as much air out as possible, and seal the
bags securely. Lay the bags down flat.
4.Have your adult partner add about 1 cup of hot tap
water to each of the 2 zip-closing plastic bags labeled
“Hot Water”. Get as much air out as possible, and seal
the bag securely. Lay the bag down flat. This bag will
serve as a heat source.
5.At the same time, use a dropper to place 1 drop of
room-temperature water in the center of 2 separate
pieces of brown paper towel.
6.Repeat step 3 with the cotton fabric swatches.
7.Allow the drops to spread for about 10-20 seconds
until they don’t seem to spread any more.
8.Place one paper towel on the bag labeled “Room
Temp”. Place the other paper towel on the bag
labeled “Hot Water”.
9.Repeat step 8 with the cotton swatches.
10.Observe every few minutes. Compare the amount
of water on each paper towel in the “What Did You
Observe?” section.
11.Thoroughly clean the work area and wash your hands.
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Evaporation Exploration page 2
Wa te r
Room temp
Room tewmapter
water
What Did You Observ
e
Does adding heat to
water increase the rat
e of
evaporation?
________________
________________
____
________________
________________
____
Which sample of wa
ter evaporated faster
, the
cotton swatch or the
paper towel?
________________
________________
____
________________
________________
____
Hot water
Hot water
Where’s the Chemistry?
The fabrics used in modern sports clothes have pores to move
water away from the skin and to the outer surface of the fabric so
that it will not soak up. The pores provide a way for sweat to evaporate faster, keeping you dry and comfortable. Evaporation happens when water is heated and goes into the air. It takes energy
to evaporate water. Heat is a form of energy, so water evaporates
more quickly at warmer temperatures. The material that soaked up
the water will have a slower rate of evaporation versus the material that contains pores for the water to easily evaporate, just like
what is used in high-tech clothing.
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Science Activities for Kids
T
he American Chemical Society develops
materials for elementary school age children
to spark their interest in science and teach developmentally appropriate chemistry concepts. The
Activities for Children collection includes hands-on
activities, articles, puzzles, and games on topics
related to children’s everyday experiences.
The collection can be used to supplement the
science curriculum, celebrate National Chemistry Week, develop Chemists Celebrate Earth Day
events, invite children to give science a try at a
large event, or to explore just for fun at home.
Find more activities, articles, puzzles and games
at www.acs.org/kids.
from the American Chemical Society
Safety Tips
This activity is intended for elementary school children
under the direct supervision of an adult. The American
Chemical Society cannot be responsible for any accidents
or injuries that may result from conducting the activities
without proper supervision, from not specifically following
directions, or from ignoring the cautions contained in the
text.
Always:
• Work with an adult.
• Read and follow all directions for the activity.
• Read all warning labels on all materials being used.
• Wear eye protection.
• Follow safety warnings or precautions, such as wearing
gloves or tying back long hair.
• Use all materials carefully, following the directions given.
• Be sure to clean up and dispose of materials properly when
you are finished with anactivity.
• Wash your hands well after every activity.
Never:
• Never eat or drink while conducting an experiment, and
be careful to keep all of the materials used away from your
mouth, nose, and eyes!
• Never experiment on your own!
For more detailed information on safety go to www.acs.
org/education and click on “Safety Guidelines”
MAIN LOGO
ACS
Chemistry for Life
PILLAR BRANDS
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ACS Publications
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American Chemical Society ©2008
High quality. High Impact
ENDORSED BRANDS
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Chemistry for Life
TM