Breaking News English

Scientists from MIT have [discover / discovered] why razor blades become blunt after repeated use. They [did / had] research into why razor blades lose their sharpness. Razor blades are 50 [times / cuts] harder than the hairs they [cutting / cut] . Even though human hair is 50 times softer than the metal of a razor blade, the hair damages the [edge / fringe] of the blade. Razor blades are made from stainless [steal / steel] . They are usually [coated / jacketed] with tougher materials like hardened carbon. The MIT scientists said that each time a blade cuts a hair, the hair causes [tinny / tiny] amounts of damage. A blade usually cuts thousands of hairs in [one / once] shaving session. This means the life of a razor blade is limited and will need to be replaced [regularly / regularity] .

The researchers used powerful [microphones / microscopes] to find out how hair damages a razor blade. They got a close-up [watch / view] of what happens [during / while] a shave when the blade cuts a hair. The blade gets damaged in a [variety / various] of ways. One way is that a [single / singled] hair creates a tiny chip on the edge of a blade. This chip becomes bigger [has / as] it cuts more hair. After more shaving, the blade loses its [able / ability] to cut cleanly and becomes blunt. A researcher said: "We are metallurgists and want to...make better [metals / meals] . In this case, it was intriguing that if you cut something very soft, like human hair, with something very hard, like steel, the hard material would [fall / fail] ." He said his team is "aiming to [solve / solution] an important engineering problem".