Để đạt thành tích cao trong kì thi sắp tới, các bạn học sinh có thể sử dụng tài liệu IELTS Academic Reading Sample 64 - Sticking power sau đây làm tư liệu tham khảo giúp rèn luyện và nâng cao kĩ năng giải đề thi, nâng cao kiến thức cho bản thân để tự tin hơn khi bước vào kì thi chính thức. Mời các bạn cùng tham khảo đề thi. | Want to walk on the ceiling All it takes is a bit of fancy footwork A If Keilar Autumn an expert in Biomechanik at Clark College in Portland Oregon has his way the first footprints on Mars won t be human. They ll belong to a gecko. Gecko toes have legendary sticking power - and the Clark College scientist would like to see the next generation of Martian robots walking about on gecko-style feet. A gecko can whiz up the smoothest wall and hang from the ceiling by one foot with no fear of falling. B Autumn is one of a long line of researchers who have puzzled over the gecko s gravity- defying footwork. Earlier this year he and his colleagues discovered that the gecko s toes don t just stick they bond to the surface beneath them. Engineers are already trying to copy the gecko s technique - but reptilian feet are not the only ones they are interested in. C Some of the most persistent hanging creatures are insects. They can defy not just gravity but gusts of wind raindrops and a predator s attempt to prize them loose. Recent discoveries about how they achieve this could lead to the development of quick-release adhesives and miniature grippers ideal for manipulating microscopic components or holding tiny bits of tissue together during surgery. There are lots of ways to make two surfaces stick together but there are very few which provide precise and reversible attachment says Stas Gorb a biologist in Tübingen Germany working on the problem. D Geckos and insects have both perfected ways of doing this and engineers and scientists would dearly love to know how. Friction certainly plays a part in assisting horizontal movement but when the animal is running up a slope climbing vertically or travelling upside down it needs a more powerful adhesive. Just what that adhesive is has been hotly debated for years. Some people suggested that insects had micro-suckers. Some reckoned they relied on electrostatic forces. Others thought that intermolecular forces between pad and leaf .
