The fourth class in Tiangong classroom is mainly about space science experiments and popular science lectures. It introduced some interesting space science phenomena and experiments to teenagers and the public, and also showed some facilities and equipment of China Space Station. The relevant knowledge is as follows:

1. The fourth lesson of Tiangong Classroom is a wonderful space science experiment and popularization activity, which was conducted by China astronauts, scientists and related experts in China Space Station.

2. Space science experiments In this course, astronauts conducted some interesting space science experiments, such as water film experiments. In the microgravity environment of the space station, water droplets can form a water film on the surface of the object instead of flowing downwards. This is because the surface tension of liquid is dominant in microgravity environment, which makes the liquid unable to flow freely.

3. Water polo optical experiment. In the microgravity environment of the space station, the water molecules on the surface of the water polo are arranged more orderly, so light can be displayed. This experiment shows the relationship between liquid surface tension and optical properties in microgravity environment. In the experiment of effervescent tablets, in the microgravity environment of space station, effervescent tablets will produce bubbles after being put into water, which is more intense than on earth.

4. Flame burning experiment. In the microgravity environment of the space station, the shape and color of flame burning are different from those on the earth. This is because the influence of fuel diffusion and buoyancy on the flame is weakened in microgravity environment, which makes the flame burn more evenly. Space technology application, space technology application is a method to apply space technology and achievements to actual production and life.

Spatial related knowledge

1, Space Science, Space Science Lectures In this course, astronauts and scientists gave some wonderful space science lectures. Space science and technology is one of the frontier fields of modern science and technology, involving astronomy, physics, chemistry, biology and other research.

2. Space breeding. Space breeding is a method of selecting seeds by using special environmental factors in space (such as microgravity and high radiation). Through space breeding, some new varieties with excellent characters can be cultivated, such as short growth cycle, high yield and strong disease resistance. These new varieties are of great significance for improving the efficiency and quality of agricultural production.

3. Space medicine. Space medicine is a subject that studies the influence of space environment on human health. In the space environment, the human body is under the action of special environmental factors such as microgravity and high radiation, which will have a series of effects and reactions on the body. The research and application of space medicine is helpful to prevent and treat some health problems caused by space environmental factors.