A rainforest is an area covered by tall trees with the total high rainfall spreading quite equally through the year and the temperature rarely dipping below 16℃. Rainforests have a great effect on the world environment because they can take in heat from the sun and adjust the climate. Without the forest cover，these areas would reflect more heat into the atmosphere, warming the rest of the world. Losing the rainforests may also influence wind and rainfall patterns，potentially causing certain natural disasters all over the world.

    In the past hundred years，humans have begun destroying rainforests in search of three major resources（资源）: land for crops，wood for paper and other products，land for raising farm animals. This action affects the environment as a whole. For example，a lot of carbon dioxide（二氧化碳）in the air comes from burning the rainforests. People obviously have a need for the resources we gain from cutting trees but we will suffer much more than we will benefit.

    There are two main reasons for this. Firstly，when people cut down trees，generally they can only use the land for a year or two. Secondly，cutting large sections of rainforests may provide a good supply of wood right now，but in the long run it actually reduces the world's wood supply.

    Rainforests are often called the world's drug store. More than 25％ of the medicines we use today come from plants in rainforests. However，fewer than 1％of rainforest plants have been examined for their medical value. It is extremely likely that our best chance to cure diseases lies somewhere in the world's shrinking (萎缩的) rainforests.

    Americans gave nearly $300 billion away last year. Do you know the reason? Beyond the noble goals of helping others, it is that giving will make them happier.

    It is a fact that givers are happier people than non-givers. According to the Social Capital Community Benchmark Survey, a survey of 30,000 American households, people who give money to charity are 43% more likely than non-givers to say they are "very happy" about their lives. Similarly, volunteers are 42% more likely to be very happy then non-volunteers.

    The happiness difference between givers and non-givers is not due to differences in their personal characteristics, such as income or religion. Imagine two people who are identical in terms of income and faith, as well as age, education, politics, sex, and family circumstances, but one donates money and volunteers, while the other does not. The giver will be, on average, over 40 percentage points more likely to be very happy than the non-givers.

    A number of studies have researched exactly why charity leads to happiness. The surprising conclusion is that giving affects our brain chemistry. For example, people who give often report feelings of euphoria, which psychologists have referred to as the "Helper's High". They believe that charitable activity produces a very mild version of the sensations people get from drugs like morphine and heroin.

    Of course, not only does giving increase our happiness, but also our happiness increases the possibility that we will give. Everyone prefers to give more when they are happy. Researchers have investigated this by conducting experiments in which people are asked about their happiness before and after they participate in a charitable activity, such as volunteering to help children or serving meals to the poor. The result is clear that giving has a strong, positive causal impact on our happiness, so does happiness on giving

    Being stuck at home doesn't mean that learning stops. In fact, it's just the opposite. Here are some activities and resources to foster kids' imagination and build their curiosity at home.

    Let's Get Down to the Science

The science lab at school may be closed, but you can still put on goggles and a white lab coat and learn at home. This Test Tube Experiment Kit will make you feel like a genius in no time. Kids will get the chance to learn about basic chemistry, physics, and more by creating pop-resistant bubbles, bouncy balls, and other objects.

    To Infinity (无穷) and Beyond

Earth is a part of the Milky Way galaxy, but did you know there are around 100 million galaxies in the universe? There are so many fun and fascinating things to learn about space that the possibilities truly go to infinity and beyond. A great way start your child's educational space adventure is with this Real Life Sticker and Activity Book.

    Take a Walk on the Wild Side

    Biology class is in session! Here's your chance to get up close and personal with a great white shark without putting on a wetsuit. This 4D Great White Shark Anatomy Kit allows you to get an inside look at what makes these predators of the deep so powerful. And then take an even deeper dive into a shark's world with I Am Shark.

    Take advantage of this time at home and find new ways to keep exploring the world around you.

A rainy day can be a chance to recharge. While you relax on the sofa with a movie, the raindrops falling on your windows might one day provide the power for your TV. This is the idea behind an invention that harvests energy from water. 

The technology is based on the triboelectric (摩擦电的) effect. An engineer at the University of Hawaii, David Ma knew that it was possible to generate electricity by rubbing two things together. So, he thought, "Why don't we use water?"

A drop of water sliding across a surface coated with two different materials would generate enough friction(摩擦) to create an electrical charge. By placing metal wires that the drop of water touched as it moved, it should be possible to harvest electricity, he reasoned. 

It worked. In fact, the researchers lit up 15 LED bulbs with a single moving water drop. 

This is not the first time that scientists have got electricity from water-generated friction. Earlier experiments, though, harvested the charge produced in a surface by a sliding drop of water. There, the surface had acted as an electrode(电极). This is different. The energy of friction is being harvested from the water itself. 

"The technology could someday power phones, sensors or other small electronics," says Christopher Oshman, an engineer at the Colorado School of Mines. "This work is a step towards harvesting the energy of moving objects all around us, including ourselves, to power the electronic devices we use every day," he says. 

"Ma has shown that the technology can work in a lab," Oshman says. Next, the Colorado researcher would like to see it tried on a larger scale, such as on an umbrella.