JSYPT2015选题

1. Packing

The fraction of space occupied by granular particles dependson their shape. Pour non-spherical particles such as rice, matches, or M&M’scandies into a box. How do characteristics like coordination number, orientational order, or the random close packing fraction depend on the relevant parameters? 堆积 被颗粒状物体占据的小部分空间取决于它们的形状，将例如米、火柴或 M&M 糖果的非球状物体倾倒进一个盒子里，相关参量如何影响如配位数、排列顺序和随机紧密堆积分数等特征？

3. Artificial Muscle

Attach a polymer fishing line to an electric drill and apply tension to the line. As it twists, the fibre will form tight coils in a spring-like arrangement. Apply heat to the coils to permanently fix that spring-like shape. When you apply heat again, the coil will contract. Investigate this ‘artificial muscle’.

人造肌肉/伪肌肉 将一个高分子聚合物的钓鱼线固定在电钻上并使其绷紧，当它扭转时，钓鱼线纤维会形成像弹簧一样排列的牢固的线圈，当再次加热时，线圈会收缩。研究这个"人造肌肉"。

4. Liquid Film Motor

Form a soap film on a flat frame.

Put the film in an electric field

parallel to the film surface and

pass an electric current through

the film. The film rotates in its

plane. Investigate and explain

the phenomenon.

液体膜电机 在平整的边框上形成一个肥皂膜，将膜放在平行于膜面的电场中并通上贯穿膜的电流，膜会在所在平面中旋转。研究并解释这个现象。

5. Two Balloons

Two rubber balloons are partially inflated with air and connected together by a hose with a valve. It is found that depending on initial balloon volumes, the air can flow in different directions. Investigate this phenomenon.

双气球 将两个橡胶气球不完全充气，并用一个带阀的塑料管连接，会发现空气由于初始气球体积不同而流向不同的方向。研究这个现象。

6. Magnus Glider

Glue the bottoms of two light cups together to make a glider. Wind an elastic band around the centre and hold the free end that remains. While holding the glider, stretch the free end of the elastic band and then release the