Show notes
單字：
centripetal (向心的), force (力量), circular (圓的), motion (動力), continue (繼續),
spin (旋轉), create (創建), marble (彈珠), jar (罐), accelerate (加速)。
句子：
- What happened when you spun the bebe in the balloon ?（It went in a circular motion around the balloon.）
- How could you pick up the marble with the jar ? （I used centripetal force to pick up the marble.）
- What is centripetal force ?（It is any force that causes an object to move in a circular path.）