英語六級聽力材料及翻譯

Ow! Why Hot Feels Cold

Kids don’t try this at home!

Have you ever dipped your toe into a very hot bath and felt a flash of icy cold just before you realize that its really burning? After you pull your toe out, you might wonder what causes very hot water to feel cold.

This odd sensation is called paradoxical cold and is caused by the temperature receptors in the skin. There are separate, specific receptors that respond to decreases or increases in skin temperature. If skin temperature drops, the cold receptors fire and if it increases, the warmth receptors fire.

However, if a strong stimulus, like very hot water, can stimulate not only the warmth receptors but also stimulate the pain receptors. These warn us that we are doing ourselves damage, and should take action to prevent it. The strong stimulus can also cause the abnormal stimulation of the cold receptors.

Over-stimulation can cause the confusing sensation of cold, hot and pain, but as long as we’re clear about pulling the toe out to safety, paradoxical cold is just another strange trick of the senses.

噢！為什麼明明是熱的卻讓人感到冰冷呢？

小孩子不要在家嘗試以下實驗！

你是否嘗試過把腳趾伸進很燙的浴盆裏卻感到瞬間的冰冷，回過神來才意識到水是滾燙的'？也許抽出腳趾之後你很想知道，是什麼原因讓人覺得這滾燙的熱水很冷。

這種怪異的感受稱為詭冷覺，其實是皮膚內的温度感受器在作祟。皮膚內分佈着獨立的專門感受器，能對皮膚温度的升降作出反應。如果皮膚温度下降了，冷感受器就發出警告，如果皮膚温度上升了，暖感受器則發出警告。

可是，如果遇到很強烈的外部刺激，比如很燙的水，不僅能激發暖感受器，而且會激發痛感受器。這些反應提醒我們，我們正在傷害自己，應該馬上採取措施制止傷害的繼續。這種強烈的刺激也會導致冷感受器被異常激發。

過度刺激會使人體對冷、暖和痛覺的感受發生錯亂，但只要我們清醒地意識到應該把腳趾挪到安全的地方，詭冷覺也只是一種奇怪的感官遊戲而已。