Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Water purification

  1. Feb 16, 2004 #1
    i have to design a device that can purify seawater using only solar energy

    i have just one idea but still not sure it would work
    the idea is to buy a plastic bucket and a long cup or long and smaller bucket. then i put the long and smaller bucket into the big plastic bucket right in the middle. than i pour the sea water into the big bucket so it surrounds the small bucket. after that i cover the big bucket with glad wrap put it in the sun. i get a pebble (rock) and place it in the middle of the glad wrap. than the water that forms on the glad warp will all gather in the center and eventually fall into the smaller bucket.. the PROBLEM IS the water formed in the smaller bucket would vapourise too

    any ideas that could help me ?
  2. jcsd
  3. Feb 16, 2004 #2
    yah it would but it would also keep going back into the smaller cup. i think.
  4. Feb 17, 2004 #3
    what i want to do is just have some water left in the small bucket
    soon as i open it. is there anyway to keep the water in the small bucket ? i just want to make it vapourise slower than the sea water in the big bucket
  5. Feb 17, 2004 #4
    Put a funnel in the top of the small bucket, large end at the top small end pointing down into the small bucket, and seal around it. The water will drop down the funnel, the vapor inside will form on the underside of the funnel and drop back into the small bucket (except the small amount that will come out through the hole at the bottom, which should form on the celephane as water drops and fall back in).
  6. Feb 19, 2004 #5
    hmmmm thats a good idea but how would i seal the funnel ?
    and.... the hole... the water from small bucket would vaporise and leak out of the hole... hmm ahhh damit!! so confusing

    thanx for the help

    anyone have anymore good ideas ?
  7. Feb 19, 2004 #6
    Silicone seal would work to seal the funnel. The funnel could be opaque white to reduce the effects of the sun on heating the water in the small bucket and the amount lost through evaporation through the hole would just drop back in anyway.
  8. Feb 19, 2004 #7


    User Avatar
    Science Advisor

    Put some lighty crumpled aluminum foil in the small bucket.

  9. Feb 20, 2004 #8

    by putting those crumpled aluminium foil in the small bucket
    what does it actually do ?

    i think the funnel idea is the best i got.. and thats what i had planned to do before posting it here.

    but there has to be a better way. have you guyz ever done this experiment before? if u did, did u guyz use any other different idea?
    what materials did u guyz use ?

    thanx heaps..~
  10. Feb 21, 2004 #9


    User Avatar
    Homework Helper
    Gold Member

    I got a good one, to prevent evaporation from the purified water.

    E-mail me, and I'll send you a picture, or plan. It is to elaborate to explain in words.

    It is very similar to your plan, but the purified water will not get any of the solar energy, which is what you want.

    Maybe you'll figure it out yourself, so I'll give you a hint.

    "Think outside of the bucket."

    E-mail: rox_jason@hotmail.com
  11. Feb 21, 2004 #10
    it is called a solar still
    a common item on offshore small boats
    or in liferafts/lifeboats
    uses a tube to carry the pure water outside the still
  12. Feb 21, 2004 #11
    i will be trying the experiment with the filter funnel tomorrow
    and i will see if its really effective or needs more improving
  13. Feb 23, 2004 #12

    i tried the filter funnel it worked ok but i want some more better way


    professors help me on this plz~!
  14. Feb 23, 2004 #13


    User Avatar
    Homework Helper
    Gold Member

    Also, make sure the bucket is black, and the surrounding area is light. All the energy will go towards the bucket.
  15. Feb 24, 2004 #14
    the idea that u gave me over the email
    that really helps
    ta again
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook