a see-saw is what ?

Seasaw is 蹺蹺板 / 搖搖板 in Chinese.

蹺蹺板，又稱為搖搖板，是指以某些東西作為支點，支撐著很長但十分狹窄的板在上方，讓一方上升時，另一方下降的遊戲。這運用了槓桿原理，並且是兒童遊樂場裡的典型遊戲。

在遊樂場的設定裡，這塊板通常會被設置在正中，而兩邊則各坐一個人然後輪流以其腳踏地使自身的那邊升上去。而在遊樂場裡的蹺蹺板通常會有扶手讓玩者抓牢。而蹺蹺板最大的問題是如果一邊的兒童比另一邊的重很多的時候，當該較重的兒童突然用力踏地或坐下不願踏地時，另一邊的兒童可能會跌下並受傷。而為了這個原因，蹺蹺板通常會安裝在柔軟的膠質地面上。

A Seesaw (also known as a teeter-totter) is a long, narrow board suspended in the middle so that, as one end goes up, the other goes down...

In a playground setting, the board is balanced in the exact center. A person sits on each end and they take turns pushing their feet against the ground to lift their end into the air. Playground seesaws usually have handles for the riders to grip as they sit facing each other... One problem with the seesaw's design is that if a heavier child allows himself/herself to hit the ground suddenly after jumping, or exits the seesaw at the bottom, the lighter child may fall and be injured. For this reason, seesaws are often mounted above a soft surface such as foam or wood chips.

In dog agility, the board is off balance so that the same end always returns to the ground after the dog has run across it.

Seesaws are also used in acrobatics, mainly to propel an acrobat on the shorter end into the air.

Seesaws, and the eagerness of children to play with them, are also used to aid in mechanical processes. For example, at the Gaviotas community in Colombia, a children's seesaw is connected to a water pump.

For the mechanics of a seesaw, see lever. The simple mechanics of a seesaw make them appear frequently in school exam paper questions on mechanical problems...

see-saw 係搖搖板

千秋
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