IYPT 2013 in Taipei, Taiwan
The IYPT 2013 will take place in Taipei, Taiwan. Further information will be announced in due time.
Problems
As decided by the IOC 2012-07-28, released 2012-08-01
PDF for printing
There are more things in heaven and earth, Horatio,
Than are dreamt of in your philosophy.
Shakespeare

1. Invent yourself
It is more difficult to bend a paper sheet, if it is folded “accordion style” or rolled into a tube. Using a
single A4 sheet and a small amount of glue, if required, construct a bridge spanning a gap of 280
mm. Introduce parameters to describe the strength of your bridge, and optimise some or all of them.
2. Elastic space
The dynamics and apparent interactions of massive balls rolling on a stretched horizontal
membrane are often used to illustrate gravitation. Investigate the system further. Is it possible to
define and measure the apparent “gravitational constant” in such a “world”?
3. Bouncing ball
If you hold a Ping-Pong ball above the ground and release it, it bounces. The nature of the collision
changes if the ball contains liquid. Investigate how the nature of the collision depends on the
amount of liquid inside the ball and other relevant parameters.

4. Soliton
A chain of similar pendula is mounted equidistantly along a horizontal axis, with adjacent pendula
being connected with light strings. Each pendulum can rotate about the axis but can not move
sideways (see figure). Investigate the propagation of a deflection along such a chain. What is the
speed for a solitary wave, when each pendulum undergoes an entire 360º revolution?
5. Levitation
A light ball (e.g. a Ping-Pong ball) can be supported on an upward airstream. The airstream can be
tilted yet still support the ball. Investigate the effect and optimise the system to produce the
maximum angle of tilt that results in a stable ball position.

6. Coloured plastic
In bright light, a transparent plastic object (e.g. a blank CD case) can sometimes shine in various
colours (see figure). Study and explain the phenomenon. Ascertain if one also sees the colours
when various light sources are used.
7. Hearing light
Coat one half of the inside of a jar with a layer of soot and drill a hole in its cover (see figure). When
light from a light bulb connected to AC hits the jar’s black wall, a distinct sound can be heard.
Explain and investigate the phenomenon.

8. Jet and film
A thin liquid jet impacts on a soap film (see figure). Depending on relevant parameters, the jet can
either penetrate through the film or merge with it, producing interesting shapes. Explain and
investigate this interaction and the resulting shapes.
9. Carbon microphone
For many years, a design of microphone has involved the use of carbon granules. Varying pressure
on the granules produced by incident sound waves produces an electrical output signal. Investigate
the components of such a device and determine its characteristics.
10. Water rise
Fill a saucer up with water and place a candle vertically in the middle of the saucer. The candle is lit
and then covered by a transparent beaker. Investigate and explain the further phenomenon.

11. Ball bearing motor
A device called a “Ball Bearing Motor” uses electrical energy to create rotational motion. On what
parameters do the motor efficiency and the velocity of the rotation depend? (Take care when
working with high currents!)
12. Helmholtz carousel
Attach Christmas tree balls on a low friction mounting (carousel) such that the hole in each ball
points in a tangential direction. If you expose this arrangement to sound of a suitable frequency and
intensity, the carousel starts to rotate. Explain this phenomenon and investigate the parameters that
result in the maximum rotation speed of the carousel.

13. Honey coils
A thin, downward flow of viscous liquid, such as honey, often turns itself into circular coils. Study
and explain this phenomenon.
14. Flying chimney
Make a hollow cylindrical tube from light paper (e.g. from an empty tea bag). When the top end of
the cylinder is lit, it takes off. Explain the phenomenon and investigate the parameters that influence
the lift-off and dynamics of the cylinder.
15. Meniscus optics
Cut a narrow slit in a thin sheet of opaque material. Immerse the sheet in a liquid such as water.
After removing the sheet from the liquid, you will see a liquid film in the slit. Illuminate the slit and
study the resulting pattern.
16. Hoops
An elastic hoop is pressed against a hard surface and then suddenly released. The hoop can jump
high in the air. Investigate how the height of the jump depends on the relevant parameters.

17. Fire hose
Consider a hose with a water jet coming from its nozzle. Release the hose and observe its
subsequent motion. Determine the parameters that affect this motion.

1.自己创造
如果一张纸被“手风琴式”折叠或者被卷成筒，那么它将更加难以弯曲。使用一张单一的A4纸和少量胶水，如果需要的话，构建一座跨越280毫米间隙的桥梁。介绍相关参数，用以描述该桥梁的强度，并优化其中的部分参数或全部参数。
2．弹性空间
大球在水平拉伸膜上滚动的动态效果和它们之间明显的相互作用通常用于说明引力场。进一步探究该系统。在这样一个“引力场世界”确定和测量明显的“引力常数”是否可能？

3．弹力球
如果你站在地面上拿着乒乓球，并释放它，它会反弹。如果乒乓球内含有液体，碰撞的性质会发生变化。探究碰撞的性质如何取决于球内液体的含量和其他相关参数。
4．孤子
沿水平轴等距离安装一链相似的摆，相邻的摆用轻绳相连接。每一个摆可以绕轴旋转，但不能侧向移动（见图）。探究沿着这样一条链的一种旋转的传播。当各摆都经历360º旋转时，孤立波的速度是多少？
5．悬浮空中
一个轻球（如乒乓球），可以被向上的气流所支撑。气流的方向可以倾斜，然而它仍然可以支撑球。探究气流倾斜的影响，并优化该系统，得出在保持球处于稳定状态的情况下，气流倾斜的最大角度。

6．彩色塑料
在明亮光线的照射下，一个透明的塑料物体（如一张空白的CD外壳）有时可以呈现各种不同的颜色（见图）。研究和解释这种现象。确定一下，当使用各种不同颜色的光源时，是否也可以看到这些颜色。
7．聆听光的声音
将一个罐子内表面的一半涂一层锅灰，并在它的盖子上钻一个孔（见图）。当连接交流电的灯泡发出的光线射到罐子的黑墙（锅灰层）时，可以听到明显的声音。解释和探究这种现象。
8．喷射和薄膜
喷射的细液体流对肥皂薄膜的作用（见图）。喷射的液体流可以渗透通过薄膜或者与薄膜合并，产生有趣的形状，这取决于相关参数。解释和探究这种相互作用，以及由此产生的形状。
9．碳麦克风
一个麦克风的设计已经涉及碳颗粒的使用很多年了。入射声波在颗粒上产生的压力变化会产生电的输出信号。探究这样一个装置的组成，并确定其特性。

10.水上升
在一个装有水的碟子中间垂直放置一根蜡烛。点燃蜡烛,然后罩上一个透明的烧杯。探究并解释发生的现象。
11.滚珠轴承电机
一种被称为“滚珠轴承电机”的装置通过使用电能产生转动。该电机的效率和转速取决于哪些参数?( 高电流工作时一定要小心！)
12.亥姆霍兹旋转木马
在低摩擦的装置上(如旋转木马)系上圣诞树球,每个球都有沿切线方向的洞。如果将这个装置放在合适频率和强度的声音环境里，该装置会开始旋转。解释这一现象并研究使该装置达到最大转速的参数。
13.蜂蜜线圈
一种细的,向下流动的粘稠液体,如蜂蜜,往往会形成圆形线圈。研究和解释这一现象。
14.会飞的烟囱
用一张轻的纸(例如一个空的茶叶袋) 制成一个空心圆筒。当点燃该圆筒的上端时,它会飞起来。解释这种现象，并探究影响圆筒起飞的参数和动力的参数。

15.半月板光学
在一张薄片状的不透明材料上剪切一条狭缝。把该材料浸泡在液体（如水）中。从液体中拿出该材料后,你将看到狭缝里有液膜。照亮该狭缝并研究液膜上的图案。
16.弹性环
将一个弹性圆环压在硬表面上,然后突然释放。圆环可以跳起来。探究圆环跳起的高度如何取决于相关参数。
17.消防水带
有一根带有喷嘴的软管，水流从喷嘴射出。释放该软管并观察其后续运动。研究影响该运动的相关参数。

马克。