所需材料 Required materials： 

1. 10顆5X3mm的強力磁鐵
2. 兩條細線分別是50cm、100cm     
3. 一些硬幣或是華司(配重用)   

1. 10 5x3mm neodymium magnets 
2. Two thin strings, 50 cm and 100 cm in length respectively 
3. Some coins or washers (for counterweight purposes) 

說明 Introduction： 

需吸附在白板、黑板或鐵製物質表面使用，讓同學們實際拉拉看所需力度的改變，可達到更棒的教學效果！

It needs to adhere to surfaces like whiteboards, blackboards, or iron materials for use, allowing students to physically pull and experience the changes in required force, achieving an even better teaching effect!

我所參考的影片 The video I referenced：