GOOD GODE, A GEODE!
LESSON OVERVIEW
Grade Levels: K-12
This tutorial will instruct participants on how to create simulated geodes with pipe
cleaners and Borax. These can be used as table decorations or ornaments. The
lesson will lead students through a discussion about geodes, solutions, and how
temperature can affect processes.
MATERIALS
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Metallic pipe cleaners (can use regular but metallic make more crystals)
Borax
Distilled water
Food coloring
Pencils or popsicle sticks
Glass jars (recycled food or canning jars)
Glass measuring cup
Pot and burner
Optional: timelapse camera such as a GoPro
STANDARDS
NGSS
MS-PS1-4.
Develop a model that predicts and describes changes in particle motion, temperature, and
state of a pure substance when thermal energy is added or removed.
NGSS
MS-PS1-2.
Analyze and interpret data on the properties of substances before and after the substances
interact to determine if a chemical reaction has occurred.
NGSS
HS-PS1-5.
Apply scientific principles and evidence to provide an explanation about the effects of
changing the temperature or concentration of the reacting particles on the rate at which a
reaction occurs.
CCSS
ELA.RST.6-12.3
Follow precisely a multistep procedure when carrying out experiments, taking
measurements, or performing technical tasks.
OBJECTIVES
 Students will create a model of a geode.
 Students will make observations about geode formation.
 Students will analyze and discuss the precipitate process and how it is affected by temperature.
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PROCEDURE
STEP 1:
Start with a brief introduction to geodes. See guiding information below for more details and vocabulary.
Discuss what students think will happen when water that carries things like minerals cools down.
STEP 2: Tell students that they will be making their own geodes today.
STEP 3: Thoroughly clean jars.
STEP 4: Coil a pipe cleaner tightly from the center to form a circular or bowl shape.
STEP 5: Attach a second pipe cleaner to the coiled pipe cleaner. Attach the other end of the second pipe
cleaner to a pencil or popsicle stick.
STEP 6: Boil distilled water (1 cup of water for each jar/geode), then turn off the heat and measure 1 cup with a
glass measuring cup. Pour this into a jar.
STEP 7: Add three tablespoons of Borax to the water in the jar, stirring until dissolved. Add food color if desired.
STEP 8: Lower the coiled pipe cleaner into the jar, laying the pencil/popsicle stick on the mouth of the jar so that
the pipe cleaner does not touch the bottom or sides of the jar.
STEP 9: Repeat the process for the remaining jars and pipe cleaners. You may need to reheat the water as hotter
water makes better geode crystals.
STEP 10: Let jars stand for at least 5 hours or overnight. (Optional: set up a timelapse camera to film the crystal
formation process.) Then remove geodes from the water and set on towels to dry. Optional: Use wire
cutters to remove extra pipe cleaner.
STEP 11: Use boiling tap water to rinse out the remaining crystal formations inside the jars.
STEP 12: Discuss student observations about the crystals. Why do you think crystals formed instead of powdered
Borax like what we put in? The Borax was dissolved into the water, why did it come back out? What
happened to the water temperature? Do you think this had any effect on the Borax? Why do you think we
used boiling hot water? What do you think would happen if we used cold water? Why? Discuss the
science behind the simulation (see guiding information below).
GUIDING INFORMATION
Geodes: Geodes are semi-hollow rocks that have crystals inside of them. Most geodes are round and spherical, but some
are cylindrical. Geodes are made when a bubble of gas forms inside of cooling rock deep inside the earth or near
volcanoes. They can also form when a plant or animal decays underground, creating a hollow space. The outside of the
geode forms a hard rock, while the inside stays hollow. As ground water moves through these hollow rocks, minerals in the
water get left inside the rock. These minerals form crystals as they leave the water solution. The crystals grow bigger and
bigger as more minerals are deposited over many years. People break open geodes in order to display the beautiful
crystals inside.
Science Behind the Simulation: The process occurring in this simulated geode formation is called recrystallization.
Recrystallization is where a solution of compounds can be dissolved in hot water and then cooled. As the solution cools,
the substance in the solution (solute) crystalizes. In this case, Borax is dissolved in water. The hotter the water, the more
the solubility of Borax increases. Hot water can hold more Borax than cold water. This is why the geode results are better
when you use boiling hot water instead of cold or warm water. When the water cools the solubility of Borax decreases, so
more and more Borax separates from the mixture and forms crystals.
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VOCABULARY
Geode
A geode is a semi-hollow rock that contains crystal formations inside its structure.
Solution
A solution is a combination of a liquid (solvent) and a solid (solute), which is evenly mixed. In this example,
a water/Borax solution.
Solvent
A solvent is a liquid that is able to dissolve substances (solutes). In this example, water is the solvent.
Solute
A solute is a dissolved substance in a solution. In this example, Borax is the solute.
Precipitate A precipitate is the solid that forms out of the solution. In this example, the Borax crystals are precipitated
from the Water/Borax solution.
RUBRIC
Target (3)
Meets (2)
Partially Meets (1)
DISCOURSE
Contributes to the
discussion with well
thought out responses
that include supporting
observations.
Contributes to the
discussion with
responses that include
at least one supporting
observation.
Contributes to
Does not contribute to
discussion, but
the discussion.
responses not relevant
or lack supporting
observations.
CONSTRUCTION
Great care is taken in
the construction
process so that the
product is neat,
attractive and follows
plans accurately.
Construction was
careful and accurate
for the most part, but 12 details could have
been refined for a more
attractive product.
Construction accurately Construction appears
followed the plans, but careless or haphazard.
3-4 details could have Many details need
been refined for a more refinement for a strong
attractive product.
or attractive product.
COLLABORATION
Works well with others
and discusses ideas in
a fair, respectful,
encouraging way and
is considerate of the
feelings of others.
Works okay with others
and discusses ideas in
a fair, respectful way,
but may not have been
encouraging.
Considers the feelings
of others.
Works with others, but
did not contribute a fair
share of work OR was
discouraging and did
not consider the
feelings of everyone.
Did not work well with
others and/or
discusses ideas in an
unfair, disrespectful
way.
REQUIREMENTS
Meets all of the
requirements for the
project.
Meets most of the
requirements for the
project.
Meets some of the
requirements for the
project.
Does not meet the
requirements for the
project.
DEMONSTRATION OF
KNOWLEDGE OF
CONTENT IN
DISCUSSIONS AND
ACTIVITIES
Does a great job
showing an
understanding of the
content covered in
class.
Does an okay job with
showing an
understanding of the
content covered in
class.
Tries but has a difficult
time showing an
understanding of the
content covered in
class.
Does not show an
understanding of the
content covered in
class.
Total
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Does Not Meet (0)
/15