Ice Cream Saturday
Students learn the chemistry of ice, salt and exothermic reactions.
Curriculum/State Standards
5.2 Physical Science: All students
will understand that physical science
principles, including fundamental ideas
about matter, energy, and motion, are
powerful conceptual tools for making
sense of phenomena in physical, living,
and earth systems science. 5.2B Changes
in matter: substances can undergo
physical or chemical changes to form new
substances. Each change involves energy.
Overview
This was a great simple chemistry lesson
where students investigated the changing
states of matter, chemical reactions,
and the properties of ice and salt while
working for their dessert. Students
learned the chemistry of ice, salt and
exothermic reactions.
Objectives
The students will investigate the effects of
temperature changes on phase changes.
The students will investigate the effects of
changes in freezing point and utilize the
law of conservation of energy.
Materials
milk
heavy cream for ice cream machine
5lb bag of sugar
vanilla flavoring
mint flavoring
sodium chloride (NaCl) table salt
3 bags of ice
1 ice chest
2 boxes of quart Ziploc bags
3 boxes of gallon Ziploc bags
10 Thermometers
10 Measuring cups 4 boxes of Plastic spoons 1 chart paper
1 set of markers
1 set of permanent markers
notebooks
pencils
pocket folders
1 Ice cream machine
ice cream cones
chocolate syrup
paper towels
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GRADE LEVEL
Readiness Activity
Students will answer pre lab questions
utilizing prior knowledge. Pre lab
questions: 1. What is a freezing point? 2.
Is freezing an exothermic or endothermic
process? 3. Is melting an exothermic
or endothermic process? 4. How does
energy flow? Vocabulary: endothermic,
exothermic Procedure: Teacher will go
over the pre lab questions and discuss
the recipe for making ice cream.
Strategies/Activities
• Add 1/4-cup sugar, 1/2-cup milk, and
1/4-teaspoon vanilla or mint to the quart
Ziploc bag. Seal the bag securely.
• Put 2 cups of ice into the gallon Ziploc
bag.
• Use a thermometer to measure and
record the temperature of the ice in the
gallon bag.
• Add 1/2 to 3/4 cup salt (sodium
chloride) to the bag of ice.
• Place the sealed quart bag inside the
gallon bag of ice and salt. Seal the gallon
bag securely.
• Gently rock the gallon bag from side to
side. It’s best to hold it by the top seal
or to have gloves or a cloth between the
bag and your hands because the bag will
be really, really, cold.
THIS WINNING PROJECT IDEA SUBMITTED BY:
Dianne Chester Tanis
George Washington Carver
East Orange, NJ
4
2
HOURS
$478
TOTAL BUDGET
Ice Cream Saturday
....continued....
• Continue to rock the bag for 1015 minutes or until the contents
of the quart bag have solidified
into ice cream. If the students
shake the bag too vigorously, be
ready to add another Ziploc bag.
• Open the gallon bag and use
the thermometer to measure and
record the temperature of the
ice/salt mixture. You will be able
to feel the mixture getting harder.
• Remove the quart bag, open it,
serve the contents into cups or
eat the ice cream right out of the
bag with spoons and ENJOY!
Culminating Activity
The students learned that liquid
(milk mixture) turns into a
solid (ice-cream). As the liquid
got colder it expanded. The
molecules in the liquid slow
down and eventually freeze in
place. The end product was
their delicious ice cream. The
students enjoyed tasting each
other’s creations. We made ice
cream using an ice machine. We
wanted to see the difference in
the process. The machine had an
inner base that had to be frozen
for 24 hr. prior to adding our
ingredients. The entire process
took 20 min., and the students
were happier with their own
creations but enjoyed seeing
another way to make ice cream.
Evaluation Method
As part of the evaluation,
students were able to answer the
analysis questions in groups.
1. What state of matter was the
milk when we began?
2. What state of matter was the
milk when we were done?
3. In order to change the phase
of milk, what had to be removed?
4. What happened to the heat
energy?
5. Why was the salt added to the
ice?
6. If you did not add sugar, would
the ice cream freeze faster or
slower?
7. Why did the outside of the bag
get wet?
8. Describe the transfer of energy
that occurred in the lab?
9. How could you improve the
recipe? Compare and Contrast:
would an ice cream machine use
the same physical energy as the
bags?
10. How did the ice cream taste?