Baking Soda Challenge
The Baking Soda design activity is a week-long, chemistry-oriented
design task that comes from the Challenges
of Physical Science curriculum. Watch MOVIE 1 for
an Quick Peek of the design scenario that asks students
to act as a consultant to a baker who needs a replacement
for yeast to make her bread rise. Specifically, teams
must determine the ratio of baking soda and vinegar
that will produce the greatest volume of the bubbly
carbon-dioxide brew that forms after mixing. After working
experimentally with a balloon, thermometer, and setup
where the bubbly mix (detergent added to make bubbles
last) raises a ping-pong ball up a transparent plastic
tube, teams are introduced a paper-based model
of molecules at work (sodium bicarbonate + acetic acid).
This gives students a mental model of the reaction that
also helps them predict the optimal ratio for a given
total mass of ingredients that yields maximum gas production
and minimal residue (after-taste) for their client.
DITC's Baking Soda section holds the following:
Students are introduced to the challenge, and begin
a "messing about" investigation with the
two ingredients, baking soda and vinegar, by observing
the products and quantities once they react.
Students conduct more qualitative experiments to determine
the nature of the reaction (endothermic) and the gas
that gets produced.
the Optimal Mix
Students use a cylindrical plastic tube and ping-pong
ball to measure the volume of gas produced with different
proportions of the active ingredients. All teams display
on a chart results of their experiments with different
baking soda/vinegar ratios.
the Chemical Reaction
Students are introduced to a model of the experiment
and using a weighing scale, paper clips, meter stick
and pieces of oaktag, confirm the proportions they
found experimentally to best meet the challenge.
- Vinegar, baking soda
- Weighing scale, 100 ml graduated cylinders
- Ping-pong ball, meter stick
- Balloons, thermometer
- 1-meter tall plastic cylinder with an open end
- Stand and clamps to hold meter stick and cylinder
- Paper clips, scissors
- Oaktag paper or manila paper stock (from folders)
Baking Soda Teachers Materials (12 page)
DESIGNS II project was funded by NSF
grant ESI-9730469. The authors are Philip Sadler, Harold
Coyle, Cynthia Crockett, Kerry Rasmussen, and Francine
Rogers. Copyright 2002 by The President and Fellows
of Harvard College, used with permission.