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Photo
1: Inside the cooling tower of a power plant
water evaporates and ascends very quickly
as water vapour. White clouds can be seen.What to do
1. Boil 5 drops of water first in an ampoule closed by a stopper with a nozzle and after that in a Cola can (3 ml).
2. Quickly dip them int cold water.
Material
Tray, high ampoule (5mL) with stopper, micro burner in a stand, aluminium beaker of a tea candle for coloured water, plastic pipette tip, micro test tube holder (wooden clothes-peg or 10 cm of insulated copper wire), empty soft drink can, container with 1 - 2 litre of cold water toilette paper, matches, methylated spirit, dropper bottle with coloured water (stale Cola).
Experiment 1
1. Add 5 drops of water into a high ampoule. Close it with a stopper pierced from upside by a pipette (nozzle).
2. Hold the ampoule with a peg, heat it above the burner until the liquid boils and water vapour appears ascends (Photo 2).
3. Quickly turn the ampoule upside down and dip its nozzle deep into the beaker full of coloured water (Photo 3).
Observation
Compare your result with Photo 4).
Explanation
At the beginning the ampoule was not empty but it contained drops of water and 6 ml of air.
During boiling water vapour replaced the air inside the ampoule.
During condensation 6 ml water vapour were transformed into a negligable small volume of liquid water. A vacuum inside the ampoule sucked it full of coloured water in a fountain.
Experiment 2
1. Add about 3 ml of water to an empty Cola can and boil it. Hold it with wet pieces of toilette paper (Photo 5).
2. As soon as the water is boiling, quickly turn the can upside down and dip it to the bottom of the container full of cold water.
Observation Compare your result with the one seen in Photo 6 and 7). Can you hear a bang?
Explanation
Like in experiment 1 water vapour replaced the (300 ml) air inside the can. During cooling these 300 ml of water vapour condensed leaving a negligable small volume of liquid water inside the can. The vacuum was equalized by in a different way, the can collapsed with a bang: right photo.
Explosion
of a can