熱對流實驗 想想看,熱空氣為何會往上浮?冷空氣又為何往下沉呢? <object width="425" height="355"><param name="movie" value="http://www.youtube.com/v/oFJuPXr-wk8&hl=en"></param><param name="wmode" value="transparent"></param><embed src="http://www.youtube.com/v/oFJuPXr-wk8&hl=en" type="application/x-shockwave-flash" wmode="transparent" width="425" height="355"></embed></object> <!-- more -->