The candles below are an example of the weight-versus-volume.
Both of the candles have the same weight (8 ounces) yet look at the difference in volume (height).
The candle on the left is a traditional paraffin based wax. The mottled looking candle is made out of a palm stearic soy combination.
This example illustrates why soapmakers prefer measuring oils by weight to ensure precise lye usage.
