Experience teaches us that a large balloon takes longer to deflate than a small one of the same kind. But what is the quantitative relation between the deflation time τ and the radius R of a balloon? A simple analysis, depending only upon elementary physics, shows that $\tau \sim R^{7/2}$—a prediction that is surprisingly easy to illustrate with a party balloon, a tape measure, and a smart-phone app.

中文翻译：

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球，膀胱和气球中的气体：使弹性球体放气所需的时间

经验告诉我们，大气球比小气球需要更长的时间才能放气。但是放气时间τ和气球半径R之间的定量关系是什么？仅仅依赖于基本物理学的简单分析表明：$\tau 〜{\mathrm{[R}}^{7/2}$-通过聚会气球，卷尺和智能手机应用程序可以轻松说明这一预测。