杠杆、滑轮和齿轮

认识一些机械装置，如杠杆、滑轮和齿轮，能让较小的力产生更大的效果。

Recognise that some mechanisms including levers, pulleys, and gears allow a smaller force to have a greater effect

学习证据 / Evidence

• 描述杠杆的工作原理：在一端施力，通过中间支点移动另一端的重物。
• 解释滑轮如何改变力的方向，并让提起物体更省力。
• 描述齿轮如何传递和改变力的大小或方向。

• Describe how a lever works: effort at one end moves a load at the other, with a pivot in between
• Explain how a pulley changes the direction of a force and can make lifting easier
• Describe how gears transfer and change the size or direction of forces

评估问题 / Assessment

{{name}}能解释跷跷板、旗杆上的滑轮或自行车的齿轮是如何让人用更小的力气移动重物的吗？

Can {{name}} explain how a see-saw, a pulley on a flagpole, or the gears on a bicycle make it easier to move heavy things with less effort?