THE HYDROMETERCalculate

Basic facts:

1 litre of water weighs 1 kg (1 000 grammes)

1 litre of alcohol weighs 0.8 kg (800 grammes)

1 litre of water weighs 1 000 grammes = which is neither
more or less than 1 kg. That gives 0 degrees on the
hydrometer (with Oechslescale).

1 litre of alcohol weighs 800 grammes, or 200 grammes less than 1 kg.
This would be 200 minus degrees on the hydrometer (with Oechslescale)

if it had a minus scale long enough (coloured scale).

1 litre water = 1 kg (1 000 grammes)

1 litre alcohol = 800 grammes

10% alcohol/water – mixture

100 ml alcohol x weight 0.8 = 80 grammes

900 ml water = 900 grammes

80
900
980 grammes

980 grammes is 20 grammes less than 1 kg = minus 20 hydrometer (with Oechslescale) degrees