Unit 1 学霸新视野外刊阅读-【拔尖特训】2023-2024学年九年级上册英语 人教版

外刊阅读 ▶ “答案与解析”见P4 重而圆的石块在水面上弹跳得更高 Have you ever spent ages searching the beach for flat(扁平的) stones to skim(掠过) across the water? Wel, you might have been wasting your time because a new study has found that heavy and rounded stones wil make bigger leaps out of the water. When you throw a thin, flat stone across the water, you wil often see it skim along the surface several times. With a round stone, the efect is diferent but no less satisfying. It might only skip once, but, if thrown right, it wil bounce (弹跳) much higher, according to researchers. Doctor Ryan Palmer and Professor Frank Smith used math to work out how the shape and weight of an object affect how it hits the water. They discovered that although some heavy stones wil sink, stones that have a special kind of curve(曲面) wil bounce. This is because the curve changes how the stone interacts(相互作 用) with the water. A stone that is rounded and heavy presses into the water more deeply and for longer. This pressure is what causes the water to make the stone upwards, ▲ . Palmer says round rocks are a game changer. “If you get a heavier rock, you can get a super- elastic(超弹性的) response, where you get a single big bounce rather than lots of litle bounces. It􀆳s very satisfying if you can achieve it,” he says. Palmer and Smith􀆳s research is al about how objects interact with surfaces, so it won􀆳t just be used to help people skim stones. The main aim of the research is to study how ice builds up on a plane w