Monday, 8 October 2012

Hard water testing method

Equipment list

Measuring cylinder (10ml, 50ml)
Boiling tubes
Bungs to fit boiling tube
Rack
Stopclock
Ruler
Soap solution
Selection of waters to test.

Method

Measure out 25ml of water to be tested and pour into the boiling tube.
Measure out 2ml of soap solution and add to the boiling tube.
Insert the bung and put your thumb over the top.
Use the stopclock to time vigorously shaking the tube for 15 seconds.
Place the tube into the rack and note the height of the foam formed from the water surface to the top of the lather.
Repeat three times for each water sample to find a mean.

Safety

Ensure the bung does not slip out during the shaking. This could go into the eyes or could leave a slip hazard. Should any tubes be droped and broken any spills should be cleared up straight away.

Results

The hardest water should produce the least bubbles and also produce a soap scum (Calcium Stearate)