A 0.50-quart jar contains 2.0 pounds of honey. 1.9 g/ml is the density of the honey.
Density is a measure of how much "stuff" is in a given space. For example, a block of the heavy element lead (Pb) is denser than the softer, lighter element gold (Au). Styrofoam blocks are less dense than bricks. Defined as mass per unit volume.
The density of an object is one of the most important and easiest physical properties to measure. Density is commonly used to identify pure substances and to characterize and estimate the composition of various types of mixtures. Density is an important concept because it can determine which substances float and which sink when placed in a liquid. In general, matter floats as long as its density is less than that of the liquid.
Solar- the sun is not always shining, for example at night you can't get any energy from the sun Wind-it's not always windy Water- there can be drought Really the main issue of all three of these is that they are not always available
