The man with the wire-frame glasses and the wrinkled blue shirt makes for an unlikely superstar.
"Today we will talk about work and energy," the 71-year-old Dutch physics professor says. He turns from his audience and begins filling a blackboard with mathematical equations.
But toward the end of the lecture at the Massachusetts Institute of Technology, Professor Walter Lewin does something that has brought him fans across the world. He does an experiment on a willing subject: himself.
PHOTO: NYT
"I have here a pendulum," he declares, dangling a huge metal ball from a line. "I am such a strong believer in the [rules of] mechanical energy that I am willing to put my life on the line."
Lewin stands against a wall with the ball touching his chin. He's ready to release the ball. He's confident that on its return it will not swing up any higher.
"This is no joke. If I don't succeed ... this will be my last lecture."
He releases the ball. It swings back, dangerously close to his chin, but does not rise any higher. The audience laughs and cheers.
"Physics works and I'm still alive," Lewin proclaims.
Performances such as this have helped turn Lewin into an Internet celebrity. He has topped the most downloaded list at iTunes U. He has also attracted fan mail from around the world.
In one lecture Lewin rides a tricycle powered by a fire extinguisher to demonstrate how a rocket lifts off. In another he beats a student with cat fur to show the effects of electrostatics.
Lewin's appeal has even spread to Iraq.
"You are now my Scientific Father," wrote an Iraqi physics teacher. "In spite of the ... war against my lovely Iraq, you made me love the USA because you are there and MIT is there."(THE GUARDIAN)
這個戴著金邊眼鏡、穿著藍色皺襯衫的男子看起來不太像個超級巨星。
這位七十一歲的荷蘭物理學教授說：「今天我們要討論功和能。」他轉身背對聽眾，開始在黑板上振筆寫下數學公式。
但就在這堂在麻省理工學院的授課結束前，華特．萊溫做了一件為他帶來世界各地仰慕者的事，他做了一個實驗，而自願受試者就是他本人。
一條線上懸吊著一顆大金屬球，他說：「這裡有一個鐘擺，我對機械動能法則深信不疑，所以願意把命賭在這條線上。」
萊溫靠牆站著，將球放在剛好碰到他的下巴位置，準備放開這顆球，他確信這顆球盪回來的位置不會高過他的下巴。
「這不是件玩笑事，如果我不成功…這就是我最後一堂課了。」
他放開球，球盪回來的位置離他的下巴只有毫髮之差，但並沒有升得更高，課堂上傳來一陣歡呼大笑。
萊溫宣布：「力學發揮作用，而我還活著。」
像這類的表演讓萊溫成了網路上的名人，他的課成為iTunes U（iTunes學院）上最多人下載的影片，他也吸引了世界各地的仰慕者寫信致意。
在某堂課上，萊溫騎了一台由滅火器提供動能的三輪車示範火箭如何升空；還有一次，他用貓的毛皮拍打一位學生以呈現靜電的作用。
萊溫的吸引力甚至遠播伊拉克。
「現在你是我心目中的科學之父，」一位伊拉克物理老師寫道：「儘管美國向我所愛的伊拉克開戰，但是因為你和麻省理工學院，所以我愛美國。」
（衛報�翻譯：袁星塵）
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