Why does a thin layer of skin appear on the milk?
This article explains the cause of thin skin on the surface of milk after heating and cooling. Because the lipase in milk breaks down fat globule membrane protein and releases free fat globule. Heating accelerates decomposition and reduces viscosity, making fat globule easily float. In addition, surface water evaporates, fat and protein (mainly lactalbumin) are solidified. The milk skin has high nutritional value.
Why does a bright path appear when light passes through milk?
This article explains the phenomenon of light passing through diluted milk and forming a bright path, which is called the Tyndall phenomenon. The British physicist Tyndall explained that the principle is that fat and protein particles in milk scatter light. Compared with pure tap water, there is no such phenomenon. Examples are also given. Tyndall phenomenon in life such as urban laser beams.
Why does jelly not melt at room temperature?
This article explains the principle that jelly does not melt at room temperature: jelly is made by adding a thickener (gelatin, agar, etc.) to water, sugar, and fruit juice. The polymer structure of the thickener increases the viscosity coefficient of the solution, making it in a semi-solid state, so it will not melt at room temperature. If the viscosity coefficient is reduced when heated, it will change back to the liquid state.
Why does it foam when adding detergent when washing dishes?
This article explains the reason why detergent can foam when washing dishes. The core component of detergent is a surfactant containing hydrophobic and hydrophilic groups; when washing, it wraps the crushed oil stains to form oil droplets, and the airflow enters the wrap to create bubbles. At the same time, the surfactant reduces the surface tension of water and keeps the foam stable.
Why can sailboats sail against the wind?
When sailing against the wind, the wind force acts vertically on the sail. Through the decomposition of force, it generates a forward thrust. By adjusting the course in a zigzag pattern, it is possible to achieve sailing against the wind.
Why could Native Americans kill prey from tens of meters away with blowgun darts?
Native American blowgunners utilize the principle of accelerating from coarse to fine air flow to shoot arrows. Combined with biological toxins, they can quickly paralyze and hunt high-altitude prey from a long distance.
Why can fire hoses spray high-speed water jets?
Fire hoses use small nozzles based on fluid mechanics to increase the speed of water flow. High-pressure water can extinguish fires and has also been used in wars to clear mines and break through defenses, playing a crucial role.
Why does the phenomenon of "an unmanned ferry crossing with a boat adrift on the water" occur?
This principle is one of the theoretical foundations for the study of navigation stability in modern navigation and aerospace technologies.
Why did the wind destroy the Tacoma Narrows Bridge?
The Tacoma Narrows Bridge collapsed due to resonance caused by the Kármán vortex street. The military marched across the bridge, and since then, the engineering design must undergo wind tunnel verification for safety.
Why study physics?
Physics is a fundamental discipline that explores the origins of nature. It uses modeling, mathematics, and experiments to reveal laws, permeates and promotes the development of human civilization and technology.
