This activity is a great way to familiarize students with polymers.
Before this activity, it would be helpful to define a polymer and talk about its
structure. (You could begin this discussion by talking about macromolecules and
the prefixes on the words "monomer" and "polymer.")
You may ask students to list some items that they use
everyday that are polymers.
The activity can be used as a part of a polymer unit or can be modified to teach basic
science concepts.
Objective:
We suggest using this unit to teach about polymers, elastomers, crosslinking, and/or structure of
organic molecules.
In this activity your students can use household items such as glue and borax and lab
chemicals such as sodium silicate and ethanol to create fun polymer balls.
Students can observe and note (by creating a table) physical properties of each type of polymer ball such
as their density, volume, texture, color, bounce height, etc.
Students can study structures of poly (vinyl alcohol), borax, sodium silicate, ethanol, and
acetic acid.
Students can learn about elastomers, polymerization and crosslinking.
Materials:
Borax can usually be found with laundry products, though it is not available
at all stores.
The liquid latex is often used to make molds for craft projects and can be
found at a craft or hobby store.
Safety:
If you choose to make the latex and vinegar ball with your students, be sure to mix in a well-ventilated area
or outside. The latex has strong fumes!
Wearing rubber gloves provides an added safety measure that can eliminate any
possible skin irritation from prolonged contact with the sodium silicate or with
the ammonia preservative in the liquid latex .
If you prepare the 5% acetic acid solution or 50% ethanol solution from the concentrated
reagents, be sure to use a fume hood and wear safety goggles.
All materials used in this lab can be washed off hands or clothes with soap and water.
If any chemical is splashed into eyes, rinse with lots of water immediately.
Tap water can be used to rinse the balls in all experiments; distilled water is
not required.
MSDS sheets are available for all chemicals, if you wish to have your students read these
in advance.
Experiment:
The instructions for making each ball can be found by clicking in the box
beneath the name of the ball you wish to create.
A printable page of this activity is available by clicking on "Printable Version" at the
bottom of the Level 3 Page.
The instructions for making each ball can also be printed by clicking on the instructions
and then clicking the print button in the pop-up box.
After the creation of your bouncy balls, they must be sealed in a plastic bag to prevent
drying.
When computing volume, students must use the radius of the spherical ball they created.
(Volume of a sphere = 4/3pr3.)
The radius can be found by placing the ball on the ruler to determine its diameter, which
can then be halved to find the radius, OR students can use a piece of string to find
the circumference and use the C=2pr
formula. It is interesting to see if students can
figure this out without teacher prompting.
Suggestions for Assessment:
An on-line computer quiz with instant feedback is available in this section.
A printable version is also available. Click here for answers.
You may also want to have students write a lab report or keep
a lab journal where they can discuss what they have learned from this experiment.
A teacher-created worksheet could also be helpful and more directly meet the
level and needs of your class.
Extensions:
The first two activites that are listed in this section of the Level 3 are
linked directly to our page and would be very helpful as pre- or post-lab
activities.
The "Story of Rubber" page has lots of history facts about rubber and its first
appearance and uses.
The "Has Your Ball Lost Its Bounce?" page has video footage and a discussion of
what happens to a rubber ball at varying temperatures.
Encourage students to apply their knowledge of the scientific method by asking
them to choose one of the polymer balls, write a hypothesis, and conduct an
inquiry lab. For example, they can observe changes in the properties of
the product when the amount of one reagent is changed.
Students may use structural formulas for other monomers to illustrate the
processes of addition and condensation polymerization.
Students may also compete to create a Super Ball - the ball that bounces highest.
Enrichment Activities:
The activities found at the bottom of the page are links to some more information and
activities involving polymers. These links will take you off our page
to other pages on The Polymer Science Learning Center site.
