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What you need
50-ml infusion bottle with a stopper pierced by a drinking straw and connected to a piece of infusion tubing. Electric hot plate, 5-ml injection bottle, digital thermometer.
Investigation
* Left: Put 30 ml Red Sea water into a 50-ml infusion bottle.
* Close it with a stopper pierced by a plastic pipette tip which is connected with a transfusion tubing.
* Insert the other end of this tubing into an injection bottle cooled by air.
* The sea water is heated on an electric hot plate: The liquid boils.
* Vapour is cooled by air inside the tubing.
Spritze o
Results
* A colourless, transparent liquid collects in the small bottle.
* Right: The digital thermometer placed inside the big stopper at the side of the tubing shows 100°C.
* Water boils at 100°C and condenses at the same temperature during cooling.
* This liquid is called pure water or distilled water.