Thursday, October 21, 2010

What does a plant do with all the water we pour on them?

To find out what the plant does with the water we give it we put a plastic bag on a sprig of a plant.  We used a Ziploc bag and taped over the part where the plant went into the bag so that it was like it was in it's own little personal green house.

The plant went on a stool in front of the slider window for a few hours in the afternoon to get a couple good hours of sunlight.  Within those few hours a little bit of condensation formed in the bag.  Squint and you can see it in the corner, it amounted to about six drops when we touched the sides of the bag to get it to all go to one corner.  

Now for the science part of it.  A plant looses about 90% of the water it absorbs through it's pores, the stomata and the leaves.  A large tree can loose up to 15,000 pounds of water in 12 hours.  We felt that when we went to the arboretum a few weeks back.  When we walked into the room where all the tropical plants were it was so humid it was hard breath.  This loss of water is called transpiration. 

I think if we had tried this experiment in the summer when it get hotter in the window we would have seen more condensation.

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