十万个为什么·科学启蒙30篇（4）

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为什么气球摩擦后能吸小纸片

Rubbing a balloon on hair transfers electrons from hair to rubber, giving the balloon a negative static charge.
Neutral paper bits have positive and negative charges evenly spread—but they become polarized near the charged balloon.
The balloon’s negative charge repels electrons in the paper, leaving the near side slightly positive and attractive.
This electrostatic force is strong enough to lift lightweight objects against gravity for a few seconds.
Dry air helps because moisture would let charges leak away quickly through thin water films.
The effect fades as charges slowly equalize or leak into the air, especially in humid conditions.
Unlike magnets, static attraction works on insulators like paper, plastic, or hair—not just metals.
You can test polarity by seeing whether two charged balloons push apart—confirming like charges repel.

听 → 读 → 学表达 → 懂 → 今天会说这一句 → 跟读录音 → 自己说一句。

Unlike magnets, static attraction works on insulators like paper, plastic, or hair—not just metals. 与磁铁不同，静电吸引可作用于纸、塑料、头发等绝缘体，而不仅限于金属。
Dry air helps because moisture would let charges leak away quickly through thin water films. 干燥空气有助于维持静电，因为湿气会通过薄水膜使电荷快速泄漏。
You can test polarity by seeing whether two charged balloons push apart—confirming like charges repel. 可通过观察两个带电气球是否相互排斥来验证电性——同种电荷相斥。

这篇中文题目最接近哪一句？为什么气球摩擦后能吸小纸片一次学校运动会的通知一份超市购物清单

课文第一句的意思更接近？用气球摩擦头发，会使电子从头发转移到橡胶，使气球带上负静电。今天学校放假了。请把窗户打开。

这一课主要在讲什么？（看英文标题） Why Rubbed Balloons Attract Paper Bits How to cook noodles A maths worksheet

Unlike magnets, static attraction works on insulators like paper, plastic, or hair—not just metals.

Unlike magnets, static attraction works on insulators like paper, plastic, or hair—not just metals.

第一版：录下来、回听、再听标准音。系统打分以后再加。

用今天的表达，自己说一句。

例子：Unlike magnets, static attraction works on insulators like paper, plastic, or hair—not just metals.