the materials were somewhat critical, as no additional materials were going to be available for us during the Expo itself. As a
result, we needed to plan for purchasing everything we needed —
We carefully reviewed the procedures and created spreadsheets
for all the materials we needed. Then we categorized the materials
into items we already had and items that needed to be purchased.
For items that needed to be purchased, we did a simple Internet
search to find a vendor. With careful planning, organizing our participation was completely doable, especially with Nancy’s aid.
The activities for children
The Oobleck and slime activities were extremely well received.
Chemically, the experiments are similar because they show the
cross-linked polymerization products that borax forms with polyvinyl acetate and polyvinyl alcohol, respectively. To a chemist, this concept is rather trivial, but to the children in our
audience, the results were nontoxic, tangible products that
could be felt, played with, and enjoyed! Allowing children
to stir the mixture as the reagents were added gave them
a feeling of inclusion and stimulated even greater interest.
The Oobleck activity even showed off the properties of a
non-Newtonian fluid, which intrigued some of the older
During the “magic breath” activity, we showed how
carbon dioxide exhaled from the lungs generated carbonic
acid, which neutralized a basic calcium hydroxide solution
(which we colored purple using a phenolphthalein indicator). As the solution became more acidic, the color faded,
which astonished the volunteers blowing bubbles into the
solution. While this was well received, interest quickly faded,
since the effect was quite brief. In contrast, the Oobleck and
slime experiments were enjoyed for much longer lengths of
time, due to the formation of lasting products.
The demonstrations drew a large crowd (since everyone
loves explosions!), but were relatively short-lived. The
elephant toothpaste was our most grandiose performance,
Unfortunately, we only had enough potassium iodide cata-
lyst for one reaction, so we waited until we drew enough people
to show it off. We supplemented this event with our can implo-
sion demonstration, which took advantage of pressure changes
due to water vapor condensation. While the elephant tooth-
paste “wowed” everyone, the can implosions served to keep
them interested while we explained the processes behind both
demonstrations. Since we required cans for crushing, we let
the kids drink the soda so we could crush the cans later… with
parental permission, of course!