Since this one has more marbles for each box part (4) than the first one (3), we can say that the second one is DENSER. Salinity adds to mass (no. of marbles) but not to the volume (size of box). Thus, the more salinity, the denser. Temperature may also affect water density. When the temperature is high, molecules in water disperse and move around more rapidy than they usually do in order to spread the heat energy.