Properties of Water
Matter and Energy
Key Concept 1 and 2: Water freezes and ice melts at 0
degrees Celsius. Water boils at 100 degrees Celsius.
Passage
As with any substance, water has the ability to change states of matter once it
reaches a certain temperature. Water begins to change from a liquid to a solid at
_____°C (Celsius), and this is called the freezing point for water. Interestingly,
the _______________ point of water also occurs at this same temperature as
water begins changing from a ______________ to a liquid. The
________________ point of water is the temperature at which water begins to
change from a liquid to a gas and this occurs at _____°C. Temperature plays an
important role in having substances like water change states of matter.
Illustration: Draw an image of what occurs when water reaches 100°C.
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Properties of Water
Matter and Energy
Key Concept 3: We can identify the boiling and melting/freezing
points of water using a thermometer.
Passage
We often use tools in science to help us accurately measure what we
observe. If we said, “This cup of milk is cold,” we might be correct, but
not accurate. We could measure the ________________ of the milk,
and we may see a reading of +7°C. Then, we could make a statement
much more accurate stating the exact temperature, instead of simply,
“This milk is ____________!” A ________________ is a tool used for
measuring temperature. These tools are marked in degrees
________________. The Celsius scale is based on the temperature
at which water melts/freezes at 0°C .
Illustration: Show a thermometer reading the freezing point of water. Label.
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Properties of Water
Matter and Energy
Key Concept 4: The boiling and melting/freezing points of a
substance are specific to that material, and can change only when
the physical properties of the material changes
(like water versus salt water).
Passage
One drizzly winter evening, the temperature dropped to 0°C, and ice
began to form on the road. The road crews spread salt on the road to
cause the ice to start ________________, which would make it less
slippery. This happens to the ice because salt dissolves in the water
around the ice and lowers the ________________ temperature. In some
cities farther ________________ of the Houston area, residents sprinkle
other substances, such as calcium chloride or magnesium chloride, on
the sidewalks to help melt the ________________! This is handy when
the temperature stays below freezing for a long period of time.
Illustration: Sketch what occurs to an icy road once salt is sprinkled over the ice.
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