Say hello to Changesite-（Y）— the sixth new lunar mineral（月球矿物）!

Chinese scientists found it in moon samples（样品）brought back by the Chang’e 5 lunar probe in December 2020. It has become the first lunar mineral found by Chinese scientists, making China the third nation in the world, after the United States and Russia, to have achieved such a success, reported China Daily.

Changesite-（Y）looks crystal（晶莹的）clear like a diamond. But its chemical content is different from any other known mineral.（A）It has a high level of rare earth（稀土）, reported China Science Daily. Li Ziying, chief scientist of the lunar sample research, said that the finding of this new mineral will help researchers study the history and physical traits（特征）of the moon. The value of the rare earth in（B）it will also be studied.

（C）Besides the new mineral, scientists also measured the content（含量）of helium-3（氦-3）from the Chang’e 5 samples. Helium-3 is a valuable fuel（燃料）that can provide safer nuclear energy（核能）. It is not radioactive（放射性的）and would not produce dangerous waste. On Earth, we have only 15 to 20 tons of helium-3 that can be used. But after studying the moon’s soil, scientists said there could be at least 1 million tons of helium-3 on the moon. That’s enough for all people on Earth to have clean energy for 10,000 years!

Have you ever seen the soldiers pile sandbags on the trenches (战壕) in battles? This is because the sandbags can stop flying bullets (子弹). So why are these little grains of sand so powerful? Now let’s do an experiment to find out the secret behind the sandbags.

Before doing the experiment, I prepared the materials, including a paper tube, two pieces of white paper, some dry sand, several rubber bands and a thin stick about 30cm long. With all these things prepared, the experiment began.

First, I covered one end of the paper tube with one piece of paper and tied it with a rubber band. Then, I broke the white paper with a stick. The paper is easy to break. After that, I put another piece of white paper at the end of the tube and filled 3/4 of the tube with sand. Now I’m holding the paper tube in one hand, inserting (插) the stick into the tube with the other hand and pressing the stick down. With sand in the tube, it’s very hard to break the paper. Do you know why?

It turns out that the force we use on the stick is not fully applied to the paper. Because there are many tiny spaces between the sand in the paper tube, when the stick is pressed down, the sand knocks and presses against each other, spreading the force everywhere inside the paper tube. As a result, only a small part of the force on the white paper is left, and it is not enough to break the white paper. That’s why a sandbag can stop a bullet.

Science Experimental Report

Invitations always make us think of something important or special. Sometimes we receive invitations to go to a meeting, a wedding (婚礼), a party or a picnic. We usually accept the invitations from our friends. However, sometimes we have to refuse the invitations for many reasons. To know more about who often makes invitations and why people may refuse the invitations, about 1,500 people were asked the relevant (相关的) questions.