What do you think makes one liquid more dense than another?I'm trying to find a liquid that I havent yet identified (color green) with a density of...

Density is defined as mass per unit volume (D=m/v). The standard against which liquid densities are compared is of course water, with a density of about 1 g/ml.  Something more dense than water has more of its molecules (mass) packed into a given space (volume); something less dense is just the opposite, having a lesser number of molecules in a given space.  Since by experiment, you've got an unknown liquid with a density 1.0028 g/ml, round the number to 1.003 and compare with known values in your textbook.