temperatures affecting rate of crystalliaztion in handwarmer

[Egypt123]

Dear whom this may concern,
I am in the tenth grade and i am doing an experiment testing supersatured sodium acetate solution in EZ heat handwramers. I placed these handwarmers in different temperatures of water baths and then once the handwarmer was the same temp as the water id snap it and time how long it takes to solidify and then right after it solidifies I would take it out of the water and measure its temperature after crystallization. I used 5 temperatures: 0degrees celsius,22 degrees celsius(room temperature),40 degrees celsius,60 degrees celsius,and 80 degrees celsius. For each temperature I had to do 5 trials. Therefore,I'd have 25 data collections. Everything worked pretty well for the first 4 temperatures. However, for the 80 degrees celsius temperature, I made the handwramers 80 degrees celsius and then snapped them and started the timer and its been almost 2 and a half hours and nothing has happened;the sodium acetetate solutions in all 5 hand warmers are still liquid and not one sign of crystallization has occured. What do I do? Do I just include that in my conclusion or do 5 more trials for another temperature? Do you think that I did something wrong while testing for the 80 degrees celsius temperature variable? Please Help! Any advice is welcome and greatly appreciated!:)
Thank you!

P.s: I got this experiment from this website(science buddies)

http://www.google.ca/search?hl=en&q=Ez% ... a=N&tab=wi ( click this link to see a pic of the hand warmer!!!)

[deleted-71882]

Hello Egypt123,

I understand that these handwarmers are reusable by putting them in very hot water to resolubilize the sodium acetate. I think you made the correct observation that the crystals don't form at 80 deg. C or higher.

Carefully obtained results from an experiment don't have to be expected to be valid. If you knew everything that would happen in an experiment, then why do it at all?

If you want to do it, you might try other temperatures below 80 deg. C and try to find the lowest temperature where the crystals don't form. That's another interesting bit of data. If you have learned any of the theory behind the crystallization, could you apply this theory and the minimum recrystallization temperature to deduce anything about the crystallization reaction?

Good luck, WW

[Egypt123]

Thank you very much

Um I guess i can come to the conclusion that since these hand warmers can only go until about 130-136 degrees farenheit (58 degrees celsius) when they are snapped. So, by using a temperature of 80 degrees celsius,it would not create any crystallization because it is higher than 58 degrees celsius-its maximum temperature that it can reach -and 60 degrees celsius most likely worked because it was very close to 58 degrees celsius. ???
Thankss

[deleted-71882]

Egypt123,

I'd say you've proved that the maximum crystallization temperature is somewhere between 60 and 80. More tests would be needed to narrow the uncertainty.

WW