Question

At what temperature is the density of water maximum? Why does water have a maximum density (other liquids do not)?

Answer 1

1. The variation of volume of water with the temperature.
2. It is evident from the graph that above $4^o$c (actually 3.98°C) water expands with increasing temperature, but from $4^o$c down to $0^o$c, it expands with decreasing temperature.
3. Figure 7.1b shows the variation of density of water with temperature.
4. The graph shows that with a rise in temperature the density of water rises and becomes a maximum for a temperature of $4^o$ C.
5. Thereafter with an increase in temperature the density falls.
6. Thus, water has a maximum density at $4^o$C.