Nationals Poster Final
Published on: Mar 3, 2016
Transcripts - Nationals Poster Final
Circuitry & DrivetrainSafety FeaturesCost
Iodine Clock Reaction
1. Solution changes color from clear to
2. Rate Law = 1.18×10-4 [IO3
3. Increasing concentration of iodate or
bisulfite will shorten the time for the
solution to turn dark, as shown in Fig. 1.
The iodide ion is generated by a slow reaction between iodate and bisulfite:
Rate-determining step: The iodate in excess will oxidize the previously
generated iodide to form iodine.
However, the iodine is reduced immediately back to iodide by the bisulfite:
(aq) + 3HSO3
(aq) à I-
(aq) + 3HSO4
(aq) + 5I-
(aq) + 6H+
(aq) à 3I2 + 3H2O(l)
I2(aq) + HSO3
(aq) + H2O(l) à 2I-
(aq) + HSO4
(aq) + 2H+
When the bisulfite is fully consumed, the iodine will survive, causing the
solution to darken.
Drifter is powered by a zinc-alkaline battery with the overall reaction of:
Zn(s) + 2MnO2(s) à ZnO(s) + Mn2O3(s)
Secondary containment for the batteries prevents leakage of chemicals.
Syringes reduce the potential for spills and provide an easy, accurate delivery of reactant.
Secondary containment for the stopping mechanism chemicals is compact and provides
reliable housing for the photoresistor and light bulb.
In the case of an emergency, flipping the large red switch will cause the car to stop.
All circuit components are housed to prevent chemical contact.
The gearbox cover serves as protection from moving parts.
The photoresistor detects light passing through the solution and
triggers the relay to open the circuit once the solution turns dark
blue. This cuts off power to the motor, causing the car to stop.
Drifter employs a zinc-alkaline battery
reaction to generate electrical
energy, which is then used to power a
motor. The stopping mechanism
utilizes an iodine clock reaction,
which turns dark after a given
amount of time, triggering the
photoresistor to cut power to the
Zn(s) + 2OH-
(aq) à ZnO(s) + H2O(l) + 2e-
2MnO2(s) + H2O(l) + 2e- à Mn2O3(s) + 2OH-
Zinc and a gelling agent are
added to a KOH solution.
Manganese dioxide, water, and a
conductor are mixed to create a
stable reaction substrate.
The reaction generates about 1.5 V and
2.0 A per cell. Three cells are attached
in series to obtain the power necessary
to move Drifter to the finish line.
Each substrate is spread thinly onto a copper plate, forming
the anode and cathode of the battery.
The entire cell sandwiches a
fabric separator that serves as a
salt bridge to facilitate ion flow.
Use of rapid-prototyping
technology such as 3D
printing and laser cutting
reduces wasted material
while ensuring precision.
Figure 1: Volume of Solution B vs. Time
y = 152.4x-0.63
R2 = 0.990
0 50 100 150 200 250
Photoresistor detects light Solution cuts off light
The gearbox motor
has a gear ratio of
1:41.7 and an overall
gear reduction ratio of
Copper Plates & Separator
Chassis & Drivetrain
• All materials are abundant in nature
• Emission-free power source
• Copper is reused, reducing waste
• Highly efficient chemical energy
A Special Thanks to: Professor Roseanna Zia, Professor Lynden Archer, Cornell
School of Chemical and Biomolecular Engineering, Cornell College of
Engineering, Cornell Student AIChE Chapter, The Leeds Family, Alumni Family
Cornell ChemE Car Team Members: Daniel Recalde, Charles Wan, Sophie Le,
James Dong, Christine Soong, Dhruv Ragunathan, Reginald Lin, Courtney Bui,
Doris Chen, Neil Mehta November 8, 2015
2015 ChemE Car National Competition - Salt Lake City, UT