Description
The ‘Thermal illusion’ introduces you to how we perceive temperature. We feel how warm something is with temperature receptors in our skin. Your body can adapt to changes in temperature as a result.
When you walk outside in winter, the blood vessels in your hands narrow, reducing heat loss. If you then wash your hands, your body needs some time to react. So, even cold water can feel hot. Conversely, that same tap water on a hot summer day feels pleasantly cooling.
You experience the same principle in this exhibit: the red side is hot (40°C), the blue side is cold (10°C). In the middle lies the temperature in between. The temperature of the middle part feels warm or cold, depending on where you place your other hand. With one hand on the warm part and one hand in the middle, the middle feels cool. With one hand on the cold part and the other on the middle, the middle feels warm. If you put one hand on the warm part and the other hand on the cold part, it can even cause a ‘burning’ sensation. Your body is confused and sends out an alarm signal!
This principle is used, among other places, in hospitals. Combining heat and cold therapies can relieve chronic pain.
Why is ‘hot’ not always the same and ‘cold’ not always the same?
- Put one hand on red and the other on blue. Hold for a moment.
- Then put both hands in the middle.
