James Gross, a psychology professor at Stanford University, has a 13-year-old daughter who loves math and science. “It hasn't occurred to her yet that's unusual,” he says. “But I know in the next couple of years, it will.”

    She's already being pulled out of class to do advanced things with a couple of other kids, who are guys. And as someone who studies human emotion for a procession, Gross says, “I know as time goes on, she will feel increasingly lonely as a girl who's interested in math and science, and be at risk of narrowing her choices in life before finding out how far she could have gone.''

    Gross' concern clearly shows what has been a touchy subject in the world of science for a long time: Why are there still so few women in science, and how might that affect what we learn from research?

    Women now make up half the national workforce, earn more college and graduate degrees than men, and by some estimates represent the largest single economic force in the world. Yet the gender gap in science persists, to a greater degree than in other professions, particularly in high-end, math-intensive fields such as computer science and engineering.

    According to US Census Bureau statistics, women in fields commonly referred to as STEM (science, technology, engineering, mathematics) made up 7 percent of that workforce in 1970, a figure that had jumped to 23 percent by 1990. But the rise essentially stopped there. Two decades later, in 2011, women made up 26 percent of the science workforce.

    One May morning, 10-year-old Khadab played in the ruins of a school near his home in northern Iraq. He saw something that looked interesting. It was yellow and plastic and looked like a ball. He reached for his new toy and, BANG!

    The last thing he remembered was a big noise. When Khadab awoke, he was in hospital. His parents stood sadly by his side. They told him he had picked up an unexploded bomb. When it exploded, Khadab lost an arm.

    He was just one of hundreds of Iraqi children who have been injured or killed by stepping on and picking up explosives left over from the war.

    These landmines (地雷) and bombs have injured and killed at least 15 people a day since Saddam Hussein's government fell on April 9. And children are the most affected.

    Iraq is among the worst landmine-affected countries in the world. Many villages in the war-torn areas are surrounded by minefields (雷区). These landmines lie on the ground between rocks, up in trees and on riverbeds.

    Even though the war in Iraq is over, many children have not returned to school. They can be seen walking the streets with the natural curiosity of young kids. Their new playgrounds are places where the fighting took place. Many boys can be seen playing with unexploded bombs. A new game is to throw the bombs and run away. Some of them get away, but too many are killed. They do this for fun, and don't realize the dangers until it's too late.

    UNICEF (联合国教科文组织) has warned children, through the TV, of the dangers of landmines and unexploded bombs in Iraq. They hope to make children aware of the dangers they face.

    “I can't imagine there's going to be a classroom in the north without scared children in it. It's so widespread,” said Sean Sutton of the British-based Mines Advisory Group (MAG).

    MAG is an organization working to clear unexploded bombs and landmines in war-torn areas.

    It is difficult to report the exact number of deaths. Sutton said MAG found 320 injuries in northern Iraq in the first month after April 9. But he said the real figure was probably much higher.

    In the fall of 1985, I was a bright-eyed girl heading off to Howard University, aiming at a legal career and dreaming of sitting on a Supreme Court bench somewhere. Twenty-one years later I am still a bright-eyed dreamer and one with quite a different tale to tell.

    My grandma, an amazing woman, graduated from college at the age of 65. She was the first in our family to reach that goal. But one year after I started college, she developed cancer. I made the choice to withdraw from college to care for her. It meant that school and my personal dream would have to wait.

    Then I got married with another dream: building my family with a combination of adopted and biological children. In 1999, we adopted our first son. To lay eyes on him was fantastic－and very emotional. A year later came our second adopted boy. Then followed son No,3. In 2003, I gave birth to another boy.

    You can imagine how fully occupied I became, raising four boys under the age of 8! Our home was a complete zoo — a joyous zoo. Not surprising, I never did make it back to college fulltime. But I never gave up on the dream either. I had only one choice: to find a way. That meant taking as few as one class each semester.

    The hardest part was feeling guilty about the time I spent away from the boys. They often wanted me to stay home with them. There certainly were times I wanted to quit, but I knew I should set an example for them to follow through the rest of their lives.

    In 2007, I graduated from the University of North Carolina. It took me over 21 years to get my college degree!

    I am not special, just single-minded. It always struck me that when you're looking at a big challenge from the outside, it looks huge, but when you're in the midst of it, it just seems normal Everything you want won't arrive in your life on one day. It's a process. Remember: little steps add up to big dreams.

    British chemist David Evans has become an overnight celebrity on Chinese social media. His chemistry experiments have attracted over 2 million followers in just a few months. Evans is a chemistry professor at the Beijing University of Chemical Technology. The 60-year-old always wears a white lab coat, a pair of safety goggles (护目镜), and smiles often. Some web users say he looks just like the “grandpa of KFC”.

    Evans has posted videos of various experiments. His most popular experiments have attracted millions of hits on video-sharing apps. Excited children's cheers and shouts can be heard in his videos. “I hope my experiments can arouse people's interest in science,” he says.

    Evans has been interested in China since childhood. In the early 1970s, before the reform and opening-up, he viewed it as a “country full of mysteries”. He first visited the Chinese mainland in 1987 to attend a chemistry conference in Nanjing, Jiangsu Province. He quit his job in the United Kingdom and moved to Beijing in 1996. Many of his friends thought he was crazy. But Evans says they just saw China's challenges but not its potential.

    Since 2011, Evans has turned to the Internet to popularize science. He learned short-video apps are also popular in small cities and rural areas. And he realized this enables him to reach more students, who lack opportunities to perform fun experiments. But even a one-minute video requires a considerable amount of work. Still, he thinks it's worth it to fulfill his responsibility to popularize science.

    His experiments always fill schools' lecture halls with laughter. Some viewers call him “a Harry Potter-like magician”, but he disagrees. “A magician never tells the secrets behind his tricks, but a scientist always gives an explanation.” He sees himself as a teacher. He performs experiments to spread knowledge, inspire thinking, remove misunderstandings and show that science can create change. Evans says he looks forward to more “chemical reactions” with China.

    Scientists in Western Australia claim to have made a new discovery—they have found gold in the leaves and twigs of trees. The researchers believe that the trees suck up the gold from deep underground, over 30 metres down. The discovery has been described as the first of its kind in the world. Australian gold exploration companies are pleased because it will make finding gold cheaper. Rather than drilling deep holes to find gold, they have more ways to examine tree leaves and branches. There is only a tiny amount of gold in the leaves. It would take 500 trees to make one gold ring. The gold is found using a special X-ray machine owned by an Australian government agency. A pure X-ray and a powerful microscope scan the leaves and branches.

    The claim that this is the first time that gold particles (微粒) have been found in living material might not be true, though. Ancient Chinese wisdom understood the connection between plants and the precious stones and minerals underneath them. They used plant life to find minerals and that was thousands of years ago. In the Zhou Dynasty, it was written in a book that a certain plant grew only near deposits of gold. Over the next 2,000 years, Chinese people wrote about different plants and how they grew, showed where minerals and precious stones such as jade, copper, lead, silver and gold were.

    Even more importantly, in the 1, 000s, Su Song described how copper, gold, silver, lead and tin were observed and taken from certain plants. These were amazing scientific discoveries. Meanwhile, this knowledge was unknown in the rest of the world until about 1, 600. This was when a British man realised that oak trees grew larger and greener where there was alum (明矾) in the ground. Maybe ancient Chinese has more knowledge to teach modern scientists.