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A Titanic situation...

August 11, 2008

Hi, I'm a grade 12 student from Australia.
I'm doing an experimental investigation assignment and I can't find any information on why cold temperatures mean that iron (in salt water) corrodes less. I understand that it has something to do with an increase in salinity and/or the cooling down of particles and loss of kinetic energy but I can't find anything more specific. My assignment is focussing on the factors of the corrosion of the RMS Titanic and I did experimental work on temperature and oxygen concentration because the Titanic was found 12460 feet below the sea's surface and was at near freezing temperature with almost no oxygen, both of which contributes to the slowing down of corrosion rates and the main thing corroding the Titanic is the bacteria that flourishes in anaerobic (no-oxygen) conditions. But I cannot find WHY the corrosion rate is slower in cold water.
Thanks for your help :)

Anna M
Student - Brisbane, QLD, Australia

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Hi, Anna. The short answer is that corrosion and almost every other chemical reaction occurs slower at lower temperature and you will understand why if you think about what heat is. Heat is the movement or vibration of atoms. The more quiescent and still an atom is, the less those atoms are bouncing around, the less likely they are to find themselves within reaction distance to an atom of another substance.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
August , 2008

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In chemistry books there are formulas to calculate the speed of a chemical reaction ,and one of the parameters is temperature. An increase of 10 degree C would double the speed.

Khair Shishani
aircraft maintenance - Al Ain, UAE
August 13, 2008

Thank you for responding so quickly to my question. Quicker than my teacher =P I would have it in my chemistry book, except its absolutely rubbish and the school won't buy new ones :). Thanks for your answers.

Anna M.
- Brisbane, QLD, Australia
August 13, 2008

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Anna,
yes, the chemical reaction goes faster with each extra degree of heat. Heat acts as catalyst and there are other conditions as well.

I am just curious about your experiment. Are you doing it on actual titanic parts? Sounds very intresting to me:-)))

Good luck

Hemant Kumar
- Florida, USA
September 4, 2008

Look up the Arrhenius Equation on the web.

George Brackett III
- Maine
September 24, 2008