Man is a sun;
and his senses are the planets.
Novalis
Sense of temperature
You use your sense of temperature to observe how hot or cold objects or your surroundings are. The sense of temperature is made up of distinct sensory receptors for hot and cold located in the dermis. There are more receptors for cold than for hot. As with the sense of touch, every part of your skin senses temperature. There is a difference, however. When something touches you, you feel which part of your body is touched. The sense of temperature is observed in relation to your own temperature and to the body surface area being exposed to coldness or heat. If you put your finger in a bucket of water, and then into water which is 3 degrees warmer, you would hardly feel the difference. You would feel some difference if you stuck your hand into the buckets, and if you submerged your entire lower arm you would feel the temperature difference even more strongly.
The larger the surface area perceiving the change in temperature, the more accurately you estimate the difference. Lying naked in a bath, you can perceive deviations of only 0.3 degrees Celsius. When the bathwater has cooled a little, you will perceive it as a large difference.
Warmth and cold enter your body through your skin. By exposing a large area of skin to warmth, more warmth can enter the body and you would feel warmer than if you only exposed a small part of your skin. Because of your sense of touch, you know that something is situated outside your body. In perceiving the temperature outside your body, however, the cold or warmth penetrates into you. Likewise, we do not feel the temperature as being only of the outside of an object, but perceive it as coming from the whole object, as radiating from the inside.
Your sense of temperature is closely connected to your own temperature. In other words, you do not measure absolute temperatures, but temperatures relative to your own. Put one hand in water at 10 degrees for three minutes, and the other in water at 40 degrees; then submerge them both in 27 degrees. For a few minutes, this water will seem cold to one hand and warm to the other. This effect slowly fades until both hands –feel the same temperature.
Temperature affects your mood more strongly than other senses. This is partly because the sense covers your whole body, and for another part because warmth or cold can make your whole body feel comfortable or uncomfortable. The cold chills you, and severe cold can numb or even paralyse you. Warmth can make you feel enthusiastic, but too much heat can cause apathy. Only moderate temperatures do not affect your mood.
You should also take account of warmth and cold for the sake of your social life. If you want to get to know somebody, radiate warmth. You can then expect warmth in return. But if you feel cold, you will feel rejected. You need to feel warmth from your fellow human beings, otherwise you cannot live in a community. There is a reason for such sayings as: to be left out in the cold.
Exercises
Fill three bowls of water at temperatures of 10, 27 and 40 degrees Celsius, respectively. Hold one hand in the 10 degree water for 3 minutes and the other in the 40 degree water. Then put both hands in the middle bowl for some minutes. Describe your observations.
Fill two buckets with water of different temperatures. The difference should be 3 degrees Celsius. Put a finger in one bucket of water for 3 minutes, and then in the other bucket. Repeat this with a hand, and if possible with your lower arm. Keep the temperature of the water constant (use a thermometer!). Describe your observations.
Measure the surface temperature of an animal, for example a cow, by placing your hands on various parts of its body (side, legs, head, horns, nose, etc). Which parts are warmer, which parts are colder? Search your memory for situations in which the atmosphere between people was warm, and situations in which the atmosphere was cool. Discuss these with your group. Can you discover any patterns?