Physics

This article focuses on the question of why a spinning top can stand upright without falling over. It introduces the long history and basic form of the top, explains the reason why the top can stand upright while spinning through the principle of inertia and the phenomenon of precession, and also illustrates the principle of traditional top games such as twirling bamboo sticks, as well as the practical application of the characteristic of keeping the direction of the axis of rotation unchanged during spinning in fields such as guns, shells, and artificial Earth satellites.

This article focuses on the issue of why woodpeckers can hammer on tree trunks at high speed without suffering from concussions, and introduces the research methods of Ivan Schwab's team from the University of California, USA, who won the 2006 Ig Nobel Prize. It elaborates on the shock-absorbing protection mechanisms evolved by woodpeckers in multiple aspects, including the hyoid bone, jaw muscles, beak, skull, brain structure, pecking angle, and eye structure. It points out that the head not being injured is the result of a combination of multiple factors, and this finding can help in the design of brain protection devices for humans.

This article focuses on the question of "why can glass or tiles be broken by scratching the surface", introducing the limitations of traditional strength theory in explaining the phenomenon of glass breaking, describing the background of British scientist Griffith's pioneering fracture mechanics and the related principles of stress concentration and low-stress fracture in fracture mechanics, and listing the applications of fracture mechanics in daily life, such as the design of tear-open points for food plastic packaging bags

This article focuses on the question of "why hot air balloons can carry people into the sky", introducing the development history of hot air balloons, explaining the principle of hot air balloons rising into the sky by air buoyancy, and elaborating on the discovery process of Archimedes' principle and its application examples in multiple fields.

This article focuses on the phenomenon that the whistle of a train becomes sharper when it approaches and quieter when it moves away, and introduces the origin of the discovery of the Doppler effect, its working principle, the Mach number parameter that affects its intensity, and the application of this effect in fields such as traffic speed measurement and medical blood flow detection.

This article focuses on the question of "why ants can fall from a height without getting hurt", and, based on the relevant principles of air resistance, explains the reasons why ants can fall from a height without getting hurt: air resistance can easily balance with the ant's gravity, making its falling speed slow; it suffers less impact from the ground; and since ants are small in size and have relatively high physical strength, the ground's impact force does little harm to them.

This article combines the event of Ko Shuangliang, who was honored as "the first flying man in Asia", driving a car to fly over the Hukou Waterfall of the Yellow River in 1997. It explains the principle of how a car can fly over the Yellow River from the perspective of the mechanics of inclined throwing, introduces the preparatory measures and safety design for the flight, and points out that the success of the flight also requires the performer to have excellent skills and great courage.

This article focuses on the issue that heavier slabs are actually safer in the "crushing a large stone on one's chest" performance, introduces the common forms and related cases of this acrobatic performance, explains the physical principles and other safety measures involved, and reminds non-professionals not to attempt it lightly.

This article focuses on the reason why geckos can climb on smooth walls, introduces the process of excluding past related hypotheses, and points out that geckos mainly rely on the Van der Waals force between the bristles on their feet and the surface of objects to achieve adhesion. Their rapid movement is related to the rapid formation and disappearance of the Van der Waals force. In addition, the adjustment of the angle of the bristles, muscle and nerve regulation, and capillary action also have an impact on their adhesion and climbing. At the same time, it mentions that there are still many mysteries of gecko feet that have not been unraveled, and that there are problems such as mutual adhesion and difficulty in converting between adhesion and detachment in current artificial bristle imitations.

This article takes Adili, a tightrope walker who is renowned as the "High-altitude Prince" of China, as an example to explain, from a mechanical perspective, why tightrope walkers hold long poles. That is, by adjusting the position of the long pole to adjust the center of gravity, the line of human gravity always passes through the supporting surface of the tightrope, thus maintaining body balance.

This article focuses on the topic of "why singing can shatter glass". Through the cases of Vitas breaking the crystal chandelier on the roof of the Kremlin during his performance and Naomi Watts shattering the glass on the hotel balcony with her screams, it explains the reason why high-pitched singing can shatter glass based on the physical principle of resonance, and introduces the definition of resonance, the factors affecting the natural vibration frequency of objects, and the relevant conditions under which glass can be shattered by singing.

This article focuses on the question of why a jack can lift a car, introduces the principles of slope-based force saving and self-locking, explains the working mechanism of mechanical jacks that use a spirally coiled slope combined with the lever principle to generate large lifting force, and also mentions that hydraulic jacks use hydraulic transmission principles. It demonstrates that the working principles of different types of jacks are basically the same.