Letter 24686

Does hot and cold air effect the rate at which rust forms?

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My name is Sarah, and I am in 10th grade. I need to know what rust is and how it forms in order to carry out my experiment on what conditions rust forms the quickest. I will be testing my problem by placing a piece of metal in a cup into a refrigerator and pouring water into the cup then draining it to simply moisten the metal. Then I will just repeat that until rust forms. That will be my moist cold air part, and I will also have a moist hot air part. For hot air, I will place the same kind and size of metal into another cup and place that outside in the sun. Every time I drain water over the cold air part, I will also drain water over the hot air part. My conclusions should be either hot air or cold air forms rust on metals the quickest, proving that people in warm temperatures, or people in cooler temperatures, should be more or less careful with everyday metal uses, for example a gardener and his or her shovel. Do you think this is a good conductive experiment?

Sarah E.
student - Providence, Rhode Island, United States

+++ First of two simultaneous responses.

It is a fair attempt. What you need to remember is that if you are trying to test the effect of one thing. (hot and cold air) you need to make that the only change between the two tests.

Will the temperature affect whether the parts stay wet or dry?
Try two tests in each temperature.

One in a sealed container to keep the moisture in and one in an unsealed container to let the moisture out.

Ciaron Murphy
- Great Britain

+++ Second of two simultaneous responses.

Sarah,

I think your experiment is worth pursuing for a tenth grader. You have a good plan, methodical, and you know the steps. You will want to know not just what happened but why.
That is what science is all about. I would suggest you use a bare sheet metal steel of the same size and thickness, and not just any metal.

This will correlate better with the shovel. Also, I would suggest using the same soil/dirt, of the same amount, in a same size glass (not metal cup) and pack it well around the metal and wet it with the same amount of water. You may have to wait for a few days to see noticeable corrosion.

Also, put the set up in a plastic bag so water will not escape/evaporate. You have to do the experiments under the same conditions (constants) except for temperature (variable) to get meaningful results.

Others may have some more suggestions.

Mandar Sunthankar
- Ft. Collins, CO