Which one of the following statements with regard to expansion of materials due to heating is not correct ?

Statement 1 is incorrect because water exhibits anomalous expansion. When ice melts at 0°C and is heated, the resulting water actually contracts (its volume decreases) as its temperature rises from 0°C to 4°C. It reaches its maximum density and minimum volume at approximately 4°C. Only after exceeding 4°C does water begin to expand normally with further heating. Statement 2 is correct as mercury thermometers rely on the thermal expansion of mercury to indicate temperature. Statement 3 is correct because engineers leave small gaps (expansion joints) between railway rails to accommodate the increase in length during hot weather, preventing buckling. Statement 4 is correct as metallic wires undergo linear thermal expansion, where length increases proportionally with temperature.