Hurricanes(飓风) are storms. They can cause terrible waves, wind and rain. They happen in the Atlantic Ocean and the Pacific Ocean most of the time.

Category(类别)

·Scientists divide(划分) them into five categories according to the wind speed.

·A Category 5 hurricane can destroy(摧毁) all the buildings.

Characteristic(特征)

·Hurricane Season usually comes on June 1^st and ends on November 30^th in the Atlantic Ocean, from May 15^th to November 30^th in the Pacific Ocean.

Danger

·It can cause flood when a hurricane comes with heavy rain.

·A hurricane has an eye. The eye means the center of a hurricane. After the eye passes, the wind and rain comes again.

Safety advice

·Stay inside during the Hurricane, or you'll be injured.

    Can plants learn and remember? Monica from Australia thinks so.

    Monica and her team members did some tests on mimosas(含羞草). The plants close their leaves quickly when people touch them. They put some mimosas in 56 pots. Every time they dropped the pots from 30cm high, the plants closed their leaves. Monica and her team members did this for a whole day. To their surprise，at the end of the day, the plants didn't close their leaves at all. It seemed that the plants learned that this action wouldn't hurt them.

    Another amazing thing was that the plants might remember things for a long time. Monica dropped the same pots of mimosas four weeks later. The plants still didn't close their leaves.

    Monica wasn't sure how plants learned and remembered. "The plants don't have brains, after all. Maybe they learn and remember with the help of their cells(细胞)," she said.

    Sheridan is a town in Indiana, USA. There are lots of trees near the public schools in the town. Their leaves turn sunlight into energy.

    In Sheridan, the Sun not just provides energy for plants. It keeps schools running, too. The schools use solar panels(太阳能电池板) to turn sunlight into energy.

    The science behind solar energy is not new. But Sheridan Community Schools is the first school district (学区) in Indiana to be completely solar-powered. The district finished putting in solar panels for all three of its schools in 2016. Some of the panels can turn to follow the Sun across the sky.

    In 2008, fewer than 1,000 schools used solar power. By 2014, there were 3,727 schools with solar panels in the USA. These numbers come from a report by The Solar Foundation. Roxie Brown, a programme director there, said that the number of schools with solar panels has continued to go up since 2014.

    Solar energy has some advantages over other energy sources (来源). Sunlight is a renewable source, which means it won't run out. Solar panels don't harm the environment. Also, sunlight is free. So by using solar power, schools can save money on energy costs. Brown thinks more schools should run on solar energy. "The Sun is Earth's energy source," she says. "We're trying to make it the energy source for our houses, cars and schools, too."

    But using solar energy isn't always easy. Solar panels can be expensive to put in. The panels also take up space. But for many schools, going solar is worth it.