今天的电瓶车课堂，从一句老话开始：「一场秋雨一场凉」。
Today’s e-bike classroom starts with an old saying: “Each autumn rain brings a cooler day.”
先问 Leo：什么叫秋雨？他说，秋天的雨。昨天下过，出门一摸，果然凉了。我接着讲：天上有冷空气，也有暖空气。它们俩一打仗，雨就下来了。
I asked Leo first: What is autumn rain? He said, rain in autumn. It rained yesterday; stepping outside, you could feel it had turned cooler. I went on: there is cold air and warm air in the sky. When the two start fighting, the rain falls.
Leo 马上问——为什么会打仗？我说，因为太阳光往南「跑」了。秋天，太阳的直射点往南移；地球正中间有条线叫赤道，直射点越过赤道，往南半球走。北边渐渐凉下来，冷空气变强，就往南冲，撞上暖空气，于是打起仗来，雨也就落了。地球像个大西瓜，是圆圆的球体；把西瓜竖着放，从正中间拦腰横切一刀，最鼓的那一圈就是赤道。
Leo asked at once—why do they fight? I said, because the sun’s rays have “run” south. In autumn, the sun’s direct rays shift south; around the middle of the Earth there is a line called the equator. When those rays cross the equator into the Southern Hemisphere, the north cools, the cold air grows stronger, pushes south, and meets the warm air—so they fight, and the rain comes down. The Earth is round like a big watermelon; if you stand a watermelon upright and slice it horizontally right across the middle, the circle around its widest part is the equator.
听完，Leo 自己总结了一句：
After listening, Leo summed it up himself:
雪是冷空气的队长，太阳是热空气的队长。 Snow is the captain of the cold air; the sun is the captain of the hot air.
六岁，已经在给天气分队了。
Six years old—and already assigning teams to the weather.
By Felix · Growth & Wealth · International Education