Here's why:

* Density: Density is a measure of mass per unit volume. Sulfuric acid has a higher density than water.

* Concentrated Sulfuric Acid: Concentrated sulfuric acid has a density of about 1.84 g/mL at room temperature, while water has a density of 1 g/mL. This means that 1 mL of concentrated sulfuric acid is about 1.84 times heavier than 1 mL of water.

Important Note: It's important to remember that the density of sulfuric acid varies depending on its concentration. Diluted sulfuric acid will be less dense than concentrated sulfuric acid.