Level 1 · Reading series
Lesson 23 · A Balloon on the Wall
Audio track 23
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Blow up a balloon. Rub it on a wool sweater for a few seconds. Then hold it near a wall. The balloon may stick to the wall without glue.
Rubbing moves some electric charges. One object can gain extra charges, while the other is left with fewer. The charged balloon can attract charges in the wall. This is called static electricity. Try it on a dry day because wet air can make the effect weaker.
Check your understanding
After reading, state the main idea in one sentence and find a line that supports it.
Chinese translation
把气球吹起来，在羊毛衫上摩擦几秒钟，再把它靠近墙壁。气球也许不用胶水就能贴在墙上。
摩擦使一部分电荷转移：一个物体得到额外电荷，另一个则失去一些。带电的气球可以吸引墙壁中的电荷。这叫静电。最好在干燥的日子试一试，因为潮湿的空气会减弱效果。
Key words and expressions
Key terms have Chinese explanations. Hover over dotted words in the English passage for word help and pronunciation when available.
- balloon
- 气球。
- rub
- 摩擦；擦。
- sweater
- 毛衣。
- stick
- 粘住；也可指‘刺入’。本文是‘粘住’。
- electric charge
- 电荷；物体所带电的量。
- gain
- 获得；增加。
- fewer
- 更少的；用于可数事物。
- attract
- 吸引；把……引过来。
- static electricity
- 静电。
- effect
- 效果；影响。
Background notes (Chinese)
静电与物体表面电荷的分布不均有关。天气干燥时，电荷较不容易散失，所以气球实验以及碰门把手时的小小放电更容易发生。雷电也涉及大量电荷的移动，但规模与家庭实验相差很远。
资料来源：Library of Congress, How does static electricity work?