Can you give me 35 good numericals on density, relative density and volume which are appropriate for the eighth grade?

The best number to begin with is the density of water: 1 g
per cubic centimeter.

The density of other common materials
can be found on many Web sites by Googling "density"

By
"Relative density" you may be thinking of "specific gravity" which is the density
relative to water.  For example, lead metal has a density of 11.6 g per cc.  Its
specific gravity is = 11.6 g per cc/ 1 g per cc = 11.6.  This means that it is 11.6
times denser than water.

What is the specific gravity of
copper metal whose density is 7.9 g per cc?  It is 7.9!  It is 7.9 times as dense as
water.

What is the specific gravity of ethyl alcohol which
as a density of .85 g per cc? .85.  It is .85 or 85% the density of
water.

I don't know what you mean by
"volume".