Small Wonders
ITEM: Accelerometer
INVENTED: 18th Century
USE: Sensing Movement
Developed in the 18th century by English physicist George Atwood, the first accelerometer— a device to measure acceleration— was taller than a full—grown man. Today's micro electromechanical sensors are as small as 3 mm square by 0.9 mm thick. When movement flips an electrode forward, it completes a circuit, indicating a change in acceleration force or direction. These tiny measurers of movement help ensure images on our phones and tablets stay upright, keep planes on course and missiles on target, and, in a lifesaving moment, signal airbags to inflate when cars crash. According to federal highway safety figures, this function had saved, when last counted, an estimated 44, 866 lives in the U.S. alone between 1980 and 2015.
ITEM: Eyeglasses Screw (螺丝)
INVENTED: 20th Century
USE: Joining Hinges
London optician Edward Scarlett was among the first to advertise temple arms for eyeglasses around 1730. Later appendages featured a door—like hinge that lets users fold their specs for travel. The first models used metal posts to attach frames to arms. But, as the refinement of industrial threading machines like lathes continued into the 20th century, tiny stainless—steel screws took that job. Over time, the fit has become standardized: Most frames now require fasteners with a shaft diameter of 1.4 mm, while some thin wire frames use ones as small as 1.2 mm. Consider that two-thirds of American adults—about 159 million people— wear prescription glasses. That's a lot of screws that could go loose. Fortunately, you can find a repair kit at nearly any drugstore.
ITEM: Mesh
INVENTED: 25,000 B.C.
USE: Stopping bugs
Weaving dates back to some 27,000 years ago, preceding the domestication of plants and animals and farming. Hungry humans may have used nets to get their preys. Since then, mesh has played an essential part in our comfort and survival. One of its most prominent current tools is the mosquito net, a protective covering in some countries. Thanks to machines that churn out cotton, polyester, polypropylene, and nylon weaves as fine as 0.6 mm, the air—permeable shields are a key tool in preventing the spread of malaria and other bug—borne illnesses. Insecticide— treated skeeter—stoppers helped prevent more than 600 million cases of malaria and saved 6.8 million lives between 2000 and 2015.
