第33屆國際青年物理學家競賽英文賽題全網首發

在2019年CUPT參賽隊員緊張備賽之時，2020年IYPT賽題已悄然發布！PT起家的BNU物理視界對此密切關注，兩任社長——趙蕓赫師姐和馬宇翰師兄馬不停蹄地認真推敲與翻譯，將中英文一并呈遞給大家，希望能對接下來一年的PTer有所幫助。全網首發，歡迎轉發！

以下為賽題

IYPT2020文字版

1. Invent Yourself

Design an instrument for measuring current using its heating effect. What are the accuracy, precision and limits of the method?

1.自己創造

設計一種利用熱效應測量電流的儀器。該方法的準確性 精確度和局限性是什么？

2.Inconspicuous Bottle

Put a lit candle behind a bottle. If you blow on the bottle from the opposite side, the candle may go out, as if the bottle was not there at all. Explain the phenomenon.

2.“隱形”的瓶子

把點燃的蠟燭放在瓶子后面。如果你從對面吹瓶子，蠟燭可能會熄滅，就好像瓶子根本不在那里一樣。解釋這一現象。

3.Swinging Sound Tube

A Sound Tube is a toy, consisting of a corrugated plastic tube, that you can spin around to produce sounds. Study the characteristics of the sounds produced by such toys, and how they are affected by the relevant parameters.

3.轉動的聲管

聲音管是一種玩具，由波紋塑料管組成，你可以旋轉它來發出聲音。研究這些玩具發出的聲音的特征，以及它們如何受到相關參數的影響。

4.Singing Ferrite

Insert a ferrite rod into a coil fed from a signal generator. At some frequencies the rod begins to produce a sound. Investigate the phenomenon.

4.會唱歌的鐵氧化物

將鐵氧化物插入由信號發生器供電的線圈中。在某些頻率下，桿開始發出聲音。研究這一現象。

5.Sweet Mirage

Fata Morgana is the name given to a particular form of mirage. A similar effect can be produced by shining a laser through a fluid with a refractive index gradient. Investigate the phenomenon.

5.甜蜜的海市蜃樓

Fata Morgana 是海市蜃樓的一種特殊形式。用激光照射具有折射率梯度的液體也可以產生類似的效果。研究這一現象。

6.Saxon Bowl

A bowl with a hole in its base will sink when placed in water. The Saxons used this device for timing purposes. Investigate the parameters that determine the time of sinking.

6.撒克遜人的碗

一個底部有洞的碗放在水中會下沉。撒克遜人使用這個裝置來計時。研究決定下沉時間的參數。

7.Balls on a String

Put a string through a ball with a hole in it such that the ball can move freely along the string. When you move the free end periodically, you can observe complex movements of the two balls. Investigate the phenomenon.

7.繩上的球

用一根繩子穿過帶孔的球，使得球可以在繩上自由移動。在繩的另一端連接另一個球。當你周期性地移動繩的自由端時，你可以觀察到兩個球之間的復雜運動。研究這一現象。

8.Soap Membrane Filter

A heavy particle may fall through a horizontal soap film without rupturing it. However, a light particle may not penetrate the film and may remain on its surface. Investigate the properties of such a membrane filter.

8.肥皂膜過濾器

一個重粒子可以穿過水平的肥皂沫而不使其破裂。然而，一個輕粒子可能穿不透薄膜，并可能停留在它的表面。研究這種薄膜過濾器的性能。

9.Magnetic Levitation

Under certain circumstances, the “flea” of a magnetic stirrer can rise up and levitate stably in a viscous fluid during stirring. Investigate the origins of the dynamic stabilization of the “flea” and how it depends on the relevant parameters.

9.磁懸浮

在一定條件下，磁力攪拌器的“磁子”在攪拌過程中可以在粘性流體中穩定地上升和懸浮。研究“磁子”動態穩定的原因及其如何依賴于相關參數。

10.Conducting Lines

A line drawn with a pencil on paper can be electrically conducting. Investigate the characteristics of the conducting line.

10.導電回路

用鉛筆在紙上畫的線可以導電。研究導電回路的特性。

11.Difting Speckles

Shine a laser beam onto a dark surface. A granular pattern can be seen inside the spot. When the pattern is observed by a camera or the eye, that is moving slowly, the pattern seems to drift relative to the surface. Explain the phenomenon and investigate how the drift depends on relevant parameters.

11.漂流斑點

用激光束照射黑暗的表面。在斑點內部可以看到顆粒狀的圖案。當用相機或眼睛觀察到這種緩慢移動的圖案時，它看起來正在相對于表面漂浮。解釋這一現象，并研究這種漂浮現象如何依賴于相關參數。

12.Polygon Vortex

A stationary cylindrical vessel containing a rotating plate near the bottle surface is partially filled with liquid. Under certain conditions, the shape of the liquid surface becomes polygon-like. Explain this phenomenon and investigate the dependence on the relevant parameters.

12.多邊形渦

一個靜止的圓柱形容器，包含一個靠近底部表面的部分填充液體的旋轉板。在一定條件下，液體表面的形狀會變成多邊形。解釋這一現象，并研究其對相關參數的依賴關系。

13.Friction Oscillator

A massive object is placed onto two identical parallel horizontal cylinders. The two cylinders each rotate with the same angular velocity, but in opposite directions. Investigate how the motion of the object on the cylinders depends on the relevant parameters.

13.摩擦振子

一個大質量物體被放置在兩個相同的平行水平圓柱體上。兩個圓柱體以相同的角速度旋轉，但方向相反。研究物體在圓柱體上的運動如何依賴于相關參數。

14.Falling Tower

Identical discs are stacked one on top of another to form a freestanding tower. The bottom dics can be removed by applying a sudden horizontal force such that the rest of the tower will drop down onto the surface and the tower remains standing. Investigate the phenomenon and determine the conditions that allow the tower to remain standing.

14.下降的塔

相同的圓盤，一個疊在另一個上面，形成一個獨立的塔。底部的圓盤可以通過施加一個突然的水平力而撤出，使塔身的其余部分掉到表面上，而塔身保持直立狀態。研究這一現象，并確定讓塔身保持屹立的條件。

15.Pepper Pot

If you take a salt or pepper pot and just shake it, the contents will pour out relatively slowly. However, if an object is rubbed along the bottom of the pot, then the rate of pouring can increase dramatically. Explain this phenomenon and investigate how the rate depends on the relevant parameters.

15.胡椒罐

如果你拿一個鹽或者胡椒粉罐，搖一搖，里面的東西就會慢慢倒出來。然而，如果一個物體沿著罐底摩擦，那么倒出的速度會急劇增加。解釋這一現象，并研究速率如何依賴于相關參數。

16.Nitinol Engine

Place a nitinol wire loop around two pulleys with their axes located at some distance from each other. If one of the pulleys is immersed into hot water, the wire tends to straighten, causing a rotation of the pulleys. Investigate the properties of such an engine.

16.鎳鈦合金發動機

將鎳鈦合金線圈繞在兩個滑輪上，使它們的軸彼此保持一定距離。如果其中一個滑輪浸入熱水中，電線就會變直，導致滑輪旋轉。研究這種發動機的性能。

17.Playing Card

A standard playing card can travel a very long distance provided that spin is imparted as it is thrown. Investigate the parameters that affect the distance and the trajectory17.撲克牌一張標準的撲克牌在它被旋轉著拋出時，它可以運動很長的一段距離。研究影響距離和軌跡的參數。