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Fresh
water is released from sea water during boiling
* Left: At a single
day such a lot of fresh water is consumed for each person in Sharm El Sheikh.
This fresh water
has to made from Red Sea water.
What
you need
15 boxes with empty minerals
water bottles, electric hotplate, metal can with five 10-ml bottles, sea
water (white colour added), closure nozzled by a pipette tip connected
to a transfusion tubing, Heparin bottle in a film canister with cooling
water.
Experiment
* Middle: Quarterfill
one of the five 10-ml bottles with sea water. Add a drop of milk.
* Close this bottle by a
stopper connected to 20 cm of transfusion tubing.
* The tubing ends in a Liquemin
bottle placed in a film canister for cooling.
* An adult heats the can
on an electric hotplate. (The
hotplate must be cooled before the demonstration!)
Observations
* Right: The sea
water boils and disappears from the bottle. Water drops re-appear in the
tubing.
* Water collected in the
Liquemin bottle is drinkable, salt remains in the 10-ml bottle.
Explanation
During boiling of sea water
only the water disappears from the bottle while salt does not.
Due to the cooling fresh
water re-appears.
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modification : 04.06.2001