Answer:
1. What is the true density of water?
The true density of water is 1 g/cm³. (Actually, the exact density if water is not really 1 g/cm³, but a bit less (very, very little less), at 0.9998395 g/mol at 40 degree Celsius)
2. What variables change the density of water?
Temperature and purity can change the density of water.
3. How does water go against the concept of "Thermal Expansion"?
When water is a liquid, the water molecules are packed relatively close together but can slide past each other and move around freely(as stated earlier, that makes it a liquid). As the temperature increases or decreases from 4 degree Celsius, the density of water decreases.