Practical tips: One trick to keep mosquitoes quiet! | Expo Daily

Practical tip: One trick to keep mosquitoes quiet!

Compared with outdoors, it seems that the probability of being bitten by mosquitoes indoors is much lower, and air conditioning has played a big role. Mosquitoes are very sensitive to temperature and humidity. They usually like warm and humid environments, while air-conditioned rooms usually maintain lower temperatures and lower humidity, which is not suitable for the survival and reproduction of mosquitoes. Generally speaking, the most favorite temperature for mosquitoes is 25-30 degrees Celsius, while the temperature in air-conditioned rooms is usually between 18-24 degrees Celsius.

Also, air conditioning systems usually create a constant flow of air, which is bad for mosquitoes. Mosquitoes are weak flying insects and they have a hard time keeping their flight stable in strong winds or constant air flow. Therefore, the air flow in an air-conditioned room can make it difficult for mosquitoes to stay and move around in the room.

Mosquitoes mainly find hosts through smell, and the odor environment in an air-conditioned room may not be consistent with the olfactory habits of mosquitoes. Air conditioning may mask or confuse the odor emitted by the human body, making it more difficult for mosquitoes to find their targets.

Image source: veer gallery

After the success of Chang'e 6 mission,

Two more good news

Zhang Yuhua of China Aerospace Science and Technology Corporation said that the success of Chang'e 6 mission represents the height of China's technology and also represents the progress of mankind. After the success of Chang'e 6 mission, there are two more good news: one is that the Chang'e 8 project has been launched , and the other is that the lunar landforms are expected to have new Chinese place names . Looking forward to it!

The endangered level is higher than that of the giant panda ! The world's critically endangered species was discovered in Beijing

Not long ago, the water ecological health monitoring team of the Beijing Haidian District Water Affairs Bureau discovered a low-spotted dragonfly-like insect for the first time while conducting a survey of aquatic insects along the Shangzhuang Reservoir. After review and identification by relevant experts from Beijing Forestry University, it was finally determined to be a critically endangered (CR) insect of the order Odonata in the class Insecta in the "Red List of Endangered Species of the World Conservation Union".

The low-spotted dragonfly belongs to the genus Dragonfly of the family Odonata in the order Odonata. It is also known as the six-spotted dragonfly and the amber dragonfly. It is a large dragonfly with colored wings and lives mostly in low-altitude river and lake wetlands. The low-spotted dragonfly was once widely distributed in North my country and East China, but its living environment has been seriously affected by urbanization and the reduction of farmland. The low-spotted dragonfly has poor adaptability to the environment and its population migration and diffusion ability is not strong, which makes it more vulnerable to environmental pressure.

The low-spotted dragonfly has special requirements for its living environment. It prefers small still water bodies and has high requirements for water quality. However, with the progress of urbanization, suitable habitats are becoming increasingly scarce, causing this species to face an extremely endangered situation.

According to the World Conservation Union (IUCN), the global population of the lesser spotted dragonfly is less than 5,000 and is declining year by year. The endangered level of the lesser spotted dragonfly is even higher than that of the national treasure giant panda, and is the same as the endangered level of the Chinese sturgeon and the Baiji dolphin, both of which are first-class national protected animals.

Why did the SpongeBob SquarePants we raised as children "grow up" and "have babies"?

Did you raise colorful balls like the one in the picture below when you were a child? After soaking for a day or two, the small plastic beads will become round and "pregnant" and "give birth" to new balls.

The official name of "SpongeBob" is Bubble Beads. The main component is polypropylene polymer, a hydrophilic resin with strong water absorption and a large expansion coefficient. It can absorb hundreds to thousands of times its own weight of water. It has high water retention and will not be squeezed out even with pressurized water. When the expansion exceeds the limit of its expansion coefficient, it will burst and release new collagen. This is the principle of Bubble Beads producing small beads.

However, as an aromatic hydrocarbon compound, it contains metal elements such as magnesium, titanium, and zinc. When the skin comes into contact with it, the heavy metals in it may penetrate into the cells and cause harm to the human body.

Bubble beads were originally used for growing flowers to ensure drainage and water retention. They can absorb excess water to prevent plants from drowning. When they absorb too much water, they can burst and release water for plants to absorb, providing a moist growth environment for plants.

You can no longer count on the “ money tree ”, but you can still use it as a guide at the village entrance!

In October 2013, Australian scientists used X-ray imaging technology to discover trace amounts of gold in the leaves of a type of eucalyptus. The particles are very small, only about one-fifth the diameter of a hair. However, there is gold in almost every leaf of this eucalyptus tree. Isn't this the legendary "money tree"?

It turns out that the root system of this eucalyptus tree is more developed than that of other trees. When it grows, if it encounters tiny gold particles, it will absorb them along with groundwater and then gather them on its branches and leaves. Unfortunately, there is very little gold on each leaf. To make a gold ring, you need to find at least 500 such "money trees" to extract enough gold.

You won't make much money by collecting these gold particles bit by bit, but they are good clues for finding gold mines and may help save a lot of survey costs!

This type of plant that absorbs and gathers underground minerals can be called "mineral indicator plants". After a long geological period, the underground metal ore bodies are dissolved, eroded and transported by groundwater, often resulting in the surface soil being rich in such metal elements. Moreover, many elements gradually become ions that can be absorbed and utilized by plants. Once they are absorbed by plants, they may be reflected in the growth of plants.

Gold particles take a ride on a eucalyptus elevator. Image credit: Melvyn Lintern et al; Nature Communications

The content is compiled from China Science Expo Weibo, Bring Science Home, People's Daily, Xinhua News Agency, Institute of Physics, Chinese Academy of Sciences, Museum

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