Final answer:
The statement that viscosity is lower if the oil is thicker is false. Thicker oils have higher viscosity, and viscosity decreases as temperatures increase due to the higher kinetic energy of the molecules.
Step-by-step explanation:
The student's question incorrectly states that viscosity is lower if the oil is thicker, which is measured at 212°F (100°C). This statement is false. Viscosity is a measure of a liquid's resistance to flow, which means thicker oils, which flow more slowly, have a higher viscosity. As temperature increases, the viscosity of motor oils decreases because the molecules gain kinetic energy, enabling them to overcome intermolecular forces that resist flow. Motor oils must maintain an effective level of viscosity across a wide range of temperatures to lubricate an engine properly, which is why viscosity control is crucial in their formulation.