The Chemistry of Water
Grade Level: Elementary
Focus Question: How does water’s structure contribute to its unique properties?
Learner Objective(s): 1) The student will be able to identify unique properties of water like
surface tension. 2) The students will be able to observe that water sticks to itself and objects like
pennies.
NGSS Standard(s): 2-PS1-1: Matter and Its Interactions; 2-ESS2-3: Earth’s Systems
IA Core Standard(s): S.K-2.PS.2: Understand and apply knowledge of characteristics of liquids
and solids; S.3-5.PS.1: Understand and apply knowledge of how to describe and identify
substances based on characteristic properties.
Main Ideas: Students observe and describe properties of water. Water sticks to itself and to
objects, forming a unique dome shape.
Materials:
Model or image of water
Activity 1: (Per group) Eye dropper, water in container, penny
Activity 2: (Per group) Eye dropper, penny, another substance (e.g. vegetable oil)
Safety/Special/Academic Language Considerations: No safety issues. Penny should be clean.
Academic language considerations include the use of vocabulary like molecules, cohesion,
adhesion, and surface tension.
Lesson Sequence:
Activity (5E) Description of activity
(Engage)
Draw a picture of a water molecule on board or show picture.
Ask students if they have seen this before. Where? What is it?
What is it made out of? Ask students to predict how many
drops of water will fit on a penny before it overflows. Record
the class’ prediction on the board.
(Explore)
Activity 1: Water Drop on a Penny
1. In each group of students, students will carefully drop
water, one drop at a time, onto the penny. Students will
count each drop.
2. Students will record the results of their activity on the
classroom board.
Time
5-10
minutes
(Explain)
10-15
minutes
Ask students how their prediction compared to the results of
their activity. Ask students why water acts like this; ask
7-10
minutes
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Property of the University of Iowa:
(Elaborate)
(Evaluate)
students to justify their reasoning.
Because of the property of water called surface tension, water
forms a tight arrangement with other water, making the drops
of water stick together and pile on the penny. The surface
tension of water causes the drops of water to stick together on
the penny instead of rolling off. The molecules of water on the
surface of the penny are attracted to each other, so they tend to
combine into one large drop rather than overflowing. The
property of water called cohesion allows water to stick to
itself. The property of water called adhesion allows water to
stick to objects like the penny. Do all liquids act this way?
Ask students to think about where else they have seen these
properties of water take place in real life. For instance, think
about some insects like mosquitos being able to “walk” along
the surface of a liquid lake. The surface tension of water
makes water at the surface of the lake strong and harder for the
insects to penetrate, allowing them to stay on the surface. An
example of the property of adhesion is shown when water can
travel up a tree trunk. The water sticks to the inside of the tree,
allowing it to travel up from the roots of the tree.
Activity 2: Comparing Substances
1. In each group of students, students will use the eye
droppers to carefully drop a different liquid, one drop
at a time, onto a penny. Students will count each drop.
2. Students will record the results of their activity on the
classroom board.
Ask students to compare the results of Activity 2 with their
prediction. Why do you think this liquid acted differently than
water? Do all liquids act similarly to water? Why is this? Ask
students to explain their reasoning.
Water has unique properties that allow it to stick to itself
(called cohesion) and other objects (called adhesion).
7-10
minutes
5-10
minutes
Assessment(s): Students will explain how water and another substance differ and what
properties make this possible.
Closure: Students name two concepts learned in today’s class about water.
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Property of the University of Iowa:
Resources
From http://sciencefairwater.com/wordpress/wpcontent/uploads/2011/01/WaterMoleculeH2Ox72.jpg
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Property of the University of Iowa: