why are the sippy cups wet?
October 1, 2008 6:14 PM Subscribe
Why do the thin, plastic things (ie, ziploc containers) in my dishwasher still wet after the drying cycle when the stainless steal and porcelain things are dry?
I thought I remember a teacher explaining that plastic is hydrophilic, whereas glass and porcelain are hydrophobic. The water molecules don't cling to glass the way they cling to plastic. I don't think temperature has anything to do with it, since everything (glass and plastic) reaches about the same temperature during the wash cycle.
posted by spikeleemajortomdickandharryconnickjrmints at 6:38 PM on October 1, 2008
posted by spikeleemajortomdickandharryconnickjrmints at 6:38 PM on October 1, 2008
Best answer: Spike has it exactly backwards.
On the hydrophilic glass and ceramic surfaces, the water forms a thin film that evaporates rapidly. On the hydrophobic glass surfaces, it beads up. The beads have a much lower surface/volume ratio than the film, and they evaporate much more slowly.
posted by mr_roboto at 7:05 PM on October 1, 2008 [3 favorites]
On the hydrophilic glass and ceramic surfaces, the water forms a thin film that evaporates rapidly. On the hydrophobic glass surfaces, it beads up. The beads have a much lower surface/volume ratio than the film, and they evaporate much more slowly.
posted by mr_roboto at 7:05 PM on October 1, 2008 [3 favorites]
Well, I learned something today. Thanks!
posted by Cat Pie Hurts at 7:09 PM on October 1, 2008
posted by Cat Pie Hurts at 7:09 PM on October 1, 2008
Great question - I was just thinking about it yesterday. Figured it had something to do with hydrophilic/phobic properties.
posted by wfrgms at 7:19 PM on October 1, 2008
posted by wfrgms at 7:19 PM on October 1, 2008
Well I fail, but that makes sense to me.
posted by spikeleemajortomdickandharryconnickjrmints at 7:44 PM on October 1, 2008
posted by spikeleemajortomdickandharryconnickjrmints at 7:44 PM on October 1, 2008
Response by poster: Thanks all. This has bugged me for a long time.
posted by shothotbot at 6:34 AM on October 2, 2008
posted by shothotbot at 6:34 AM on October 2, 2008
mr_roboto, don't you mean on the hydrophobic plastic surfaces?
posted by entropic at 7:06 AM on October 2, 2008
posted by entropic at 7:06 AM on October 2, 2008
I leave the reason as it's a sign that plastic sucks.
posted by dasheekeejones at 8:26 AM on October 2, 2008
posted by dasheekeejones at 8:26 AM on October 2, 2008
mr_roboto, don't you mean on the hydrophobic plastic surfaces?
Yes. Yes, I do.
posted by mr_roboto at 2:33 PM on October 2, 2008
Yes. Yes, I do.
posted by mr_roboto at 2:33 PM on October 2, 2008
This thread is closed to new comments.
Hopefully someone will come in with the exact science of it.
posted by Cat Pie Hurts at 6:21 PM on October 1, 2008