How does temperature affect the flow rate of water in pipes?

The correct response highlights that warmer water flows more easily due to a reduction in viscosity. Viscosity is a measure of a fluid's resistance to flow; as temperature increases, the molecules in the water gain kinetic energy and move more freely. This decrease in viscosity allows water to flow through pipes more efficiently, resulting in a higher flow rate.

In contrast, colder water has a higher viscosity, which can impede flow and result in slower movement through the pipes. The statement that temperature has no effect overlooks the fundamental principles of fluid dynamics and the significant impact changes in temperature have on fluid properties. The claim that hot water becomes heavier is also misleading; temperature increases do not inherently make water heavier but rather make it less viscous, facilitating faster flow. This understanding is crucial for plumbing applications, where managing flow rates effectively can impact system performance.