This episode covered a wide spread of practical science knowledge, from kitchen appliances and plastics to astronomy, aviation, materials, and insect societies. Here is a reorganized set of notes based on the explanations given during the quiz segments.
Everyday science
An induction cooker heats food through electromagnetic induction. The changing magnetic field generates induced currents in a conductor, and the resulting heat cooks the food. That is why it works with metal cookware, such as an iron pan. Different metals have different magnetic properties, so heating efficiency also varies. To improve performance, cookware designed for induction use often has a bottom layer containing a ferromagnetic material with stronger magnetic conductivity.
Plastics are mainly made from resin. They are non-conductive and do not rust. Because they can be molded easily into many shapes, they are widely used in daily life. At the same time, their poor biodegradability means they can create serious environmental pollution.
A disposable heat pack releases warmth through an exothermic chemical reaction. When the outer packaging is opened, oxygen from the air becomes available, allowing the reaction to continue and produce heat over time.
Light and color
In the visible spectrum, red light has the longest wavelength and the lowest frequency, while violet light has the shortest wavelength and the highest frequency. Since wavelength equals wave speed divided by frequency, wavelength and frequency are inversely related. Energy is proportional to frequency, so violet light carries more energy than red light.
Blue light, being closer to violet in the spectrum, also has a relatively short wavelength and high frequency. Waves with shorter wavelengths scatter more easily. In the atmosphere, suspended particles continuously scatter the blue portion of natural light, which is why the sky appears blue.
People and discoveries
Shiing-Shen Chern was a Chinese mathematician who studied at Nankai University and Tsinghua University. Often honored as the father of differential geometry, he received the Wolf Prize and later founded the Nankai Institute of Mathematics.
Stephen Hawking is regarded as one of the most outstanding physicists of the modern era. He was born on the 300th anniversary of Galileo Galilei’s death. Hawking made major contributions to black hole theory and wrote A Brief History of Time.
At the beginning of 2018, the Chinese Academy of Sciences cloned two macaques, which were named Zhong Zhong and Hua Hua.
Space and planets
In ancient times, Venus was known as the Morning Star. It is one of the eight planets in the solar system, and its orbit is the closest to a circle, with the smallest eccentricity. Venus rotates in the opposite direction from its revolution around the Sun, which makes its rotation extremely slow. It is also described here as the only planet in the solar system without a magnetic field.
Flight and lift
For safe operation, aircraft ideally take off and land into the wind. Compared with a tailwind, a headwind increases the aircraft’s speed relative to the air. Because of the shape of the wing, this helps generate more lift, making takeoff and landing safer.
During takeoff and landing, pilots extend the flaps on the trailing edge of the wings according to operating procedures. These flaps provide additional lift, allowing the aircraft to take off safely within a limited distance. During landing, flaps also help slow the aircraft down while still providing extra lift at lower speed, so that the vertical forces allow for a stable descent and touchdown.
Materials and their properties
Gold melts at about 1064°C. It is relatively soft, which is why it can be shaped into many kinds of jewelry.
The main component of diamond is carbon, and it can burn at high temperatures.
Crystal is mainly made of silicon dioxide, with a melting point of around 1700°C.
Social insects
A bee colony is a matriarchal society. Both the queen bee and the worker bees are female. Male bees mainly serve a reproductive role, providing females with sufficient sperm for reproduction. Ants are another example of a matriarchal insect society.