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Ice Experiments
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This experiment is courtesy of 
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Fun With Ice: Really Cool Experiments
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Developers:
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Kathleen B. Horstmeyer
Gladwyne School
Gladwyne, PA 19035 |
Dr. Paul Reibach
Agricultural Products Development Research
Rohm and Haas Company
Spring House, PA 19422 |
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This
unit is a series of lessons dealing with various aspects of
temperature, ice, and freezing. Individual lessons revolve around
melting ice, the freezing point, making ice cream, and the birth of ice
crystals. The experiments are designed to encourage observation skills
and to enhance the student's understanding of scientific principles. Experiments 1 to 4 are done in teams. Active participation by
all team members is encouraged by assigning individual responsibilities
to all team members. The students should be reminded that scientists
generally work in teams. Following the experimental section, the
students are invited to participate in a scientific convention and
present their findings. As part of the convention, the students are
challenged to explain how their findings relate to the manufacturing of
ice cream and to find a practical use for their discoveries.
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SAFETY
Several important safety issues must be considered:
- It is highly recommended that you use alcohol thermometers only. Alcohol thermometers are generally fill with a colored liquid. Mercury is not recommended due to its toxic properties.
- Care
should be taken when handling glass thermometers of any type. Do not
use them for stirring. Be careful not to bang the bulbs on any hard
surfaces.
- If a thermometer breaks be sure to clean up all glass fragments with a hand held vacuum cleaner.
- If salt gets into the ice cream mixture be sure not to eat it (it will taste really bad anyway).
- Safety glasses should be worn while performing the hands-on experiments.
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Topic Area:
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Experiment #1 : Ice Cubes and Salt
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Introduction:
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Experimenting
with the water/ice mixture is much more than having fun with a "cold"
substance. While students are participating in the water/ice
activities, they are developing skills in the art of scientific
investigation. Students will form small laboratory teams to investigate
the water/ice mixture. They will learn how scientists describe the
"properties" of a substance. During the lab sessions, they will
observe, hypothesize, and experiment with water/ice to determine its
unique properties. Students will be challenging each other to define
the properties of the water/ice mixture more accurately while refining
their communication skills. The experiments following the introduction
will allow active participation by all students, thus broadening their
understanding of the water/ice mixture using the skills of a real
scientist. |
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Grade
Levels:
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K-5 |
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Goal:
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Observe an ice cube alone, with salt and with sugar.
Predict change in the ice cube over time.
Discuss changes of the ice cube alone, with salt and with sugar. |
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Specific
Objectives:
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Students
will describe the properties of ice. Students will observe that the ice
is melting. Students will observe that salt increases the rate at which
ice melts compared to adding nothing or sugar. |
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Materials:
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Ziploc® bag #1 Labeled control
Ziploc® bag #2 Labeled salt
Ziploc® bag #3 Labeled sugar
Plastic teaspoon |
Ice Cubes
Plastic Ziploc® Bags
Salt, Sugar
Plastic sheet or paper to cover work areas |
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Background:
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Observation
skills are important for any scientific investigation. The experiments
that follow in this series deal with the properties of salt, water, and
ice. Many substances are known to effect the properties of water and
ice, with salt being the most common. |
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Procedure:
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Using
three Ziploc® bags, place an ice cube of the same size into each
Ziploc® bag. Measure one teaspoon of salt and gently sprinkle the salt
onto the ice cubes in Ziploc® bag 2 . Measure one teaspoon of sugar and
gently sprinkle the salt onto the ice cubes in Ziploc® bag 3. Seal the
bags. Observe the three ice cubes to estimate the rate of the melting
process. Compare when no ingredient is added, and when salt or sugar
are added to the ice cubes. Discuss predictions relating to the changes
the ice cubes will have over time. |
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Questions:
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*What does the ice cube feel like?
*Does the ice cube feel different with sugar or salt? How?
*Did both ice cubes melt in the same way? Why?
*What can you do to help ice melt?
*What is happening to the ice cube as you hold it?
*Would the container or article you place the ice cube in influence the rate of melting ? |
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Topic Area:
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Experiment #2: Freezing Point Depression
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Grade
Levels:
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K-5 |
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Goal:
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Observe
the effects of salt on ice and on an ice water mixture. Measure the
temperature of ice and ice water with a thermometer after each teaspoon
of salt is added. Record temperature each time salt is added to the
mixture. |
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Specific
Objectives:
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Learn
how to read a thermometer. Students will investigate the temperature
lowering as each teaspoon of salt is added to the mixture. |
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Materials:
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Salt
Water
Crushed Ice
Stirrers
Plastic Teaspoons
Glass Baby Food Jars |
Petri Dishes
Graph for Class
Graph for Students
Measuring Beaker
Thermometers
Shallow bowls for salt |
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Background:
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students
will be introduced to scientific variability when they compare their
results with other groups. The addition of salts (various types)
results in lowering the freezing point of the solution. This lowering
is called the freezing point depression. This is the same phenomenon
that allows salt to melt ice on the road. |
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Procedure:
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Using
25 ml of water and 100 ml of crushed ice, students will stir this
mixture; then using a thermometer, observe and record this temperature
on their graph. Students will add one gram of salt to the water/ice
mixture (one teaspoon can be substituted for one gram), then observe
and record the temperature on their graph. Students should repeat this
procedure until they reach -10 degrees c. More ice should be added if
necessary. |
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Theory:
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Why
is this happening? Why does the temperature go down? Why does the ice
melt? These are the most common question you will hear about this
experiment. Although the principles involve thermodynamics, the study
of energy, and are quite complicated, there is a simple answer. When
any type of salt, e.g. sodium chloride, is added to water, the freezing
point is lowered and the boiling point is raised. Basically, plain
water freezes at 0 degrees centigrade and boils at 100 centigrade. Salt
water will not freeze until the temperature is below 0 centigrade. The
more salt...the lower the freezing point. In the above experiment
energy is lost from the water in the form of heat. This heat is used to
melt the ice. Since heat is lost from the water the temperature of the
water goes down. Since there is now salt dissolved in the water it
cannot freeze again, hence we observe a lowers temperature. |
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Questions:
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*What happens to water and ice when salt is added to this mixture?
*What happens to the temperature when salt is added to the mixture?
*Why are the numbers different between the groups?
*What variables would cause these differences?
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Topic Area:
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Experiment #3: Making Cream Into Ice-Cream
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Grade
Levels:
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K-5 |
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Goal:
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Students will consolidate all their previous Ice/Water/salt/temperature experiences to make Ice-cream. |
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Specific
Objectives:
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Students will make Ice-cream using common household ingredients without specialized equipment. |
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Materials:
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Glass Beakers or Glass Baby Food Jars
Crushed Ice
Bucket to hold Ice
Plastic sheet to cover work area
Stirrers (3 for each student)
Half and Half Cream
Small vials to dispense ingredients
1/8 teaspoon vanilla |
Thermometers
Scooper
Measuring plastic teaspoon
Water
Salt
Kool Aid Drink (for Water Ice)
Large container for mixing
1 teaspoon sugar |
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Background:
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Ice-cream
is made from freezing cream, flavoring, and sugar over a period of
time. In order to make ice-cream creamy and smooth, the mixture must be
stirred during the freezing process. This lesson will consolidate what
we have learned about ice, water, and salt mixtures. |
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Procedure:
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Stir
100 ml of crushed ice and 5-6 grams of salt. If desired test the
temperature with your thermometer after each gram of salt has been
added. Students should understand that they are lowering the Freezing
Point. When the Freezing Point has been lowered, students will place
the glass beaker or a glass baby food jar onto the Ice/Water/salt
mixture. The teacher should prepare a mixture of cream, vanilla, and
sugar. Dispense 25-50 ml of the mixture to each student. Add to glass
jar in ice mixture. Stir the cream mixture until you have turned the
cream into ice-cream. Taste the ice-cream. |
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Questions:
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*What happens to the cream when the beaker is placed onto the Ice/Water mixture?
*Will you need to lower the temperature of the Ice/Water mixture? Why?
*What should you add to the Ice/Water mixture?
*How will you accomplish lowering the temperature?
*What is happening to the cream as you lowered the temperature of the Ice/Water mixture? |
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Topic Area:
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Experiment #4: The Birth and Growth of Ice Crystals
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Grade
Levels:
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K-5 |
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Goal:
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Observe the crystal design pattern starting to form (just before the slush stage). Discuss what you see. |
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Specific
Objectives:
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Investigate the crystal design pattern forming in the petri dish by initiating (poking slightly) with a stirrer. |
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Materials:
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Crushed Ice
Glass Petri Dishes
Kool-Aid Drink
Plastic bowls
Plastic sheet to cover work area
Individual Flash Lights |
Salt
Stirrers
Overhead Projector
Aluminum trays
Plastic trays
Glass Container for Crushed Ice |
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Background:
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Freezing
occurs when water is cooled down; the molecules move more slowly,
causing the water molecules to come together and begin the formation of
an ice crystal. Usually this process takes a long period of time
because the cooling is done slowly. This process can be speeded up by
rapid cooling to temperatures just below the freezing point. This
process is known as super cooling. When ice crystals form from a super
cooled water solution, the crystals form very rapidly. Under these
condition the ice crystals can actually be seen to grow. |
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Procedure:
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Using
a Kool-Aid drink, place some orange Kool-Aid into a petri dish.
(Experiments prior to this experiment dealt with reading temperatures
on a thermometer and discovering the degrees just below the freezing
point). Students prepare a bowl of ice and salt. If desired, test the
ice/salt mixture with a thermometer to make sure that the temperature
is below the freezing point. Place the petri dish on the ice/salt
mixture; watch patiently for 3-5 minutes. Poke the liquid slightly a
few times with a rod during this waiting period. Then, the ice CRYSTAL
will start forming! Amazingly, it continues to grow very quickly and
you can observe this process very vividly. The growing will last about
1 minute. Student should hold a flashlight under the petri dish to
observe the crystal structure. A follow-up to this experiment is to do
the same experiment on an overhead projector. Light shining through the
glass petri dish from the overhead projector or a flashlight allows the
close visibility of the crystal formation and structure. |
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Questions:
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Before:
*What will happen to the Kool-Aid mixture on the petri dish?
*How can we use the materials available to change the properties of Kool-Aid?
*If we poke the warm liquid slightly with a stirrer, what do you think will happen? Why?
*When you poke the super cooled liquid slightly with a stirrer, what do you think will happen?
Why?
After:
*Did anything happen when you poked the super cooled liquid? What?
*Why did we place the petri dish onto the crushed ice salt mixture?
*What do you call the process that you just observed?
*If we leave the petri dish on the crushed ice for a longer period, what happens?
*Do you think that you can stop the crystals from growing? |
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Additional Literature:
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Water. Copycat Magazine Vol. 8 No. 4. 1993
The Water Journey. Eleanore Schmid. North-South Books. 1990
The Magic School Bus at the Waterworks. Joanna Cole. Scholastic. 1987
Letting Swift River Go. Jane Yolan. Little Brown. 1992
Water, Stones, Fossils, Bones. Karen K, Lind. National Science Teachers Association. 1991
Water Science Experiments for Young Children. Rosemary Althouse and Cecil Main Teachers College Press NY. 1975
Sink or Swim-The Science of Water. Barbara Taylor. Random House .1991
Water and Ice. Joan Westley. Creative Publications. 1988
Water Science. Deborah Seed. Addison-Wesley. 1992
Science With Water. Helen Edom. EDC Publications. Tulsa Oklahoma.
Investigating Water. A Teachers Guide. Delta Science Module. Delta Education. 1988
Science Club Liquid Magic. Philip Watson. Walker Books LTD. 1982
A Walk in the Rain. Ursel Scheffer. Putnam and Sons. N. Y.
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This experiment is courtesy of
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