* agarose gels (weighing of agarose and buffer);
* AA gels (weighing of all components);
* 1x electrophoresis buffers from the stocks (weighing of water and stock solution);
* salt solutions;
* in the cases of viscous liquids, large volumes etc.
It is really convenient if there are two balances in the laboratory. One (that is used more often) is with the 0.01g gauge and the range to 1.5-3kg. It is used for preparation of large volumes of buffers, balancing of centrifuge tubes etc. The other balance has 0.0001g gauge and the range of 50-100g. It is used for preparation of small volumes of buffers (it is sufficient if the neighboring laboratory has such a scale).
If the density of the solution is known, it is possible to calculate the water volume (weight) that is necessary for its preparation. It is very convenient, because otherwise phrase "add water to the final volume…" forces you to use the graduated cylinder for the preparation of solution (calibration of all other laboratory glassware is only approximate).
See also: /web-links/
what liquids do not readily dissolve in water subject to a contastant agitiation and are lighter so remain on the surface? (other than oil) preferable also that do not leave a film like oil does on thinngs
can i find the density of liuquids by making and using a straww hydrometer
Density and solubility are two different things.
You should put densities of liquids peole might have heard of or have in their home. For example, honey, Mountain dew, Liquid soap, coffee, or Shampoo.