Question

Is density of ice affected melting rate or is adding objects

Answer 1

It isn't a major factor in determining melting point.

Here is a table of compounds with their densities and melting points.

Compound; Density/g·mL⁻¹; mp/°C

hexane; 0.65; -95

ethanol; 0.79; -114

water; 1.00; 0

chloroform; 1.48; -64

dimethyl ether; 1.97; -141

sodium chloride; 2.16; 801

methyl iodide; 2.28; -66

mercury; 13.59; -39

The density increases as we go down the list, but the melting points vary all over the map.

The intermolecular attractions are much more important factors in determining the melting point.