第十七课

seventeen17

Revelation of sole pattern鞋底花纹的启示

1．Have you observed the pattern of the sole? What is the effect of these patterns?

你观察过鞋底的花纹吗?这些花纹有什么作用?

Material package材料包

2．Towels, small pieces, etc毛巾、小木块等

Activity process活动过程

3．Play a push-pull game, what do you find?玩一玩推拉游戏，有什么发现?

4．When we push or pull an object on the ground, there is a force between the object and the ground that hinders the motion of the object.

当我们在地面上推或拉一个物体时，在物体和地面之间会产生阻碍物体运动的力。

5．A force like this is friction.像这样的力是摩擦力。

6．What factors are related to the friction force?摩擦力的大小与什么因素有关?

7．It may be related to the smoothness of the contact surface.可能与接触面的光滑程度有关。

8．Also possible...还可能....

9．Do an experimental study. 做个实验研究一下吧。

Thinking Navigation思维导航

10．What are the same conditions compared to experiment 1 and experiment 2? What are the different conditions? Which experiment has a large friction force? What does it mean?

实验1和实验2相比，相同条件是什么?不同条件是什么?  哪个实验中的摩擦力大?说明了什么?

11．What about experiment 1 as compared to experiment 3? 实验1和实验3相比呢?

Information Card资料卡

12．The force on an object can be measured by a dynamometer物体受到的力可以用测力计测量。

13．Use force measurement timing to first set the pointer to the zero scale line.

使用测力计时，要先将指针调到零刻度线处。

14．A unit of force is Newton, or cow, expressed in N".力的单位是牛顿，简称牛，用“N”表示。

15．Each dynamometer has a certain range of measurements.每个测力计都有一定的测量范围。

16．In order to obtain more accurate data, the average value is obtained after multiple measurements.

为了得到更准确的数据，实验时，一般多次测量后求平均值。

17．When an object is pushed or pulled on a horizontal plane, the rougher the contact surface, the greater the friction; the heavier the object is pushed or pulled, the greater the friction.

在水平面上推或拉一个物体时，接触面越粗糙，摩擦力越大;被推或拉动的物体越重，摩擦力越大。

18．What is the relationship between friction and our lives?摩擦力与我们的生活有什么关系?

19．If there is no friction...假如没有摩擦力....

Outreach activities拓展活动

20．Learn how people prevent skid when roads freeze in snow days.

了解雪天路面结冰时人们是怎样防滑的。

 Unit evaluation单元评价

Knowledge Park知识乐园

concept概念

Fill in a fill, say say. 填一填，说一说。

 steamer轮船

 buoyancy浮力

apply应用

 concept概念

Common forces常见的力

 spring balance 弹簧秤

elastic force弹力

apply应用

概念

 concept摩擦力

apply应用

The Hall of Science科学殿堂

Some fish have a swim bladder (biao) in the body. 有的鱼身体内有鱼鳔(biao)。

Find information and understand the swim bladder. 查找资料，了解鱼鳔的用途。

 swimming bladder 鱼鳔

Reflection on Space反思空间

My Harvest我的收获

●The sole pattern increases the friction force. 鞋底的花纹可以增大摩擦力。

I want to improve我想改进的

●Experiments on whether sinking objects are subject to buoyancy. 下沉物体是否受到浮力的实验。

I want to continue exploring the我想继续探究的

●What are the ways to reduce friction?减小摩擦力的方法有哪些?