1.  Water and Cola

W01 Most of the earth is covered by water
W02 Distribute water: From litre (L) to millilitre (mL)
W03.Distribute water: From millilitre (mL) to microlitre (µL).
W04 How much weighs water?
W05 Water becomes invisible by evaporation and by boiling
W06 Density: Compare 1-ml samples of Cola, water, Dead Sea water
W07 The volume of water and Cola increases during freezing
W08 Making electricity, electricity in water, salt water and Cola
W09 Distilled water made of Cola

W10 Salt sugar, citric acid: Can you make them invisible?
W11 Salt sugar, citric acid: Can you make them visible again?
.W12 Water dissolves only a small amount of air
........ Fresh water not only an environment for fishes
........ Sea water an environment for animals, plants (and men?)
.......  Mineral water
W13 Lemon juice corrodes fossiles and egg shells
W14 Lemon juice contains two different acids
W15 Sour cherries and an opponent of acids
W16 Soap reduces the surface tension of water
W17 Soap solution to test for the hardness of washing water
W18 Washing-up liquid to mix oil and water

3. Chemical reactions of water and its solutions

W19 Oxyhydrogen gas from water
W20 About water molecules and hydrogen atoms
W21 One salt, two colours: Cobalt chloride forms crystals with water molecules
W22 Cobalt chloride paper to test for water vapour in air.