Capillary action and temperature

[Sarah C]

My daughter (1st grade, 7 years old) wanted to investigate capillary action for her science fair project. She decided to find out whether temperature affects capillary action in carnations. We put three white carnations in three glasses of red water and put one in the oven at 140 degrees F, one in the refrigerator and one on the kitchen counter (air temp about 68 degrees F). The carnation in the oven turned completely pink in about 3 hours, then the stem collapsed. The one on the kitchen counter was edged in red in about 5 hours, but 10 hours after that (15 hours after the experiment began) the room-temp carnation has not changed much. The one in the fridge has hardly any red on it at all. We'll have to check the flowers again this afternoon, but I suspect that the two remaining ones will still be white with red edging. I think my daughter can conclude that she found that temp does affect the speed of the capillary action. But one question I can't answer is why the carnation in the oven turned uniformily pink whereas the other two seem to be just getting edged in red. I do have a theory that it might have to do with the oven drying the carnation out, but I really am not sure...

Thanks in advance for helping me help my daughter.

EDIT: Forgot to add that this is due tomorrow!!!

[ChrisG]

Hi Sarah C.,
Welcome to the Ask an Expert forum. Those are very interesting results, and a great way for your child to learn about physical and biological sciences. Ideally, you would want to use three or more carnations in each temperature condition, but maybe that would be overkill for a 1st grade project. Lets assume that the results you saw would be the same in any number of trials. The possible responses to temperature that could affect your results include
1) physical processes affecting transport of water & dye
2) biological processes affecting the uptake and redistribution of water due to transpiration through active plant tissues.
Specifically, I can imagine that the pink vs red coloring could be affected by higher rates of diffusion at higher temperature, or more uniform transpiration across the surface of the petal as the plant tries to cool itself by opening more stomata. There might also be physical changes to the plant structure and redistribution of the dye due to desiccation, as you mentioned.

Here are a couple of web pages describing the response of plant & flower transpiration to temperature changes:
http://www.actahort.org/members/showpdf ... rnr=624_57
http://books.google.com/books?id=03S6Vb ... n#PPA84,M1

I hope that helps.
Good luck!
Chris

[Sarah C]

Thank you Chris, that is a big help!

[ChrisG]

Great! Good luck with that project. Please let us know if you have any more questions.