Question

why density of water is high at 4 degree Celsius and why not 5 degree Celsius and 3 degree Celsius

Answer 1

because 4 degree celsius is the normal temperature of a room

Answer 2

When the ice melts to liquid water, the structure collapses and the density of the liquid increases. At temperatures well above freezing, the molecules move faster and getfurther apart. The density decreases as temperature increases. ... Thus, the density of water is a maximum at 4 °C.