“A ball rolls differently on different surfaces, some surfaces create more friction, with the ball friction is a force that slows down things that are moving.
一个球在不同的表面滚动是不同的,有些表面会产生更多的摩擦,摩擦会减轻物体在表面的运动。
然后会让孩子尝试不同的表面,球的运动是怎样的,
Tap the button or tap t to get the ball moving. You think will help the ball roll far enough to reach the hole.
轻击按钮使球移动。选择你认为会帮助球滚入洞内表面。
当孩子尝试不同的表面时,也会解释结果,
例如上图中的选择sandpapar,但是摩擦力太大,球没有进洞,他会提醒孩子,Oh,the sandpaper is too rough.