Answer
The hand that contains vegetable oil doesn't feel cool because it evaporates at a slower rate than water.
Work Step by Step
The hand that contains vegetable oil doesn't feel cool because it evaporates at a slower rate than water. This is because the hand feels cooler when a liquid evaporates from the surface. Since vegetable oil has a higher boiling point than water it will evaporate slower than water and thus the hand that contains vegetable oil doesn't feel cool.
