Why do you feel different temperature when you switch your finger from hot to tap water?

When you switch your finger from hot water to tap water, your skin’s thermoreceptors rapidly adapt to the change in temperature. In hot water, your skin becomes accustomed to the higher temperature, so when you switch to cooler tap water, it feels significantly colder due to the sudden contrast. This phenomenon is a result of how our sensory receptors respond to changes in temperature, leading to a heightened perception of the difference. Thus, the sensation of temperature is relative to what your skin has just experienced.