popular science

26 POPULAR SCIENCE

Developed in the 18th century by English physicist George Atwood, the irst accel-

erometer—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 lips an electrode forward, it completes a circuit, indicating a

change in acceleration force or direction. These diminutive invigilators of movement

help ensure images on our phones and tablets stay upright, keep planes on course and

missiles on target, and, in a lifesaving incarnation, signal airbags to inlate when cars

crash. According to ANCAP and Monash, car airbags have saved 2700 lives and

prevented or reduced the severity of over 36,000 injuries since the early 1990s.

ITEM:

Accelerometer

INVENTED:

18th century

USE:

Sensing movement

We’re biased toward big. Big ideas, big data, big

science— the more mega an achievement, the more

attention we shine on it. But what about the smaller

innovations that make our lives easier, safer, and longer?

Scattered throughout the remainder of this issue, you’ll

find a celebration of the very small, and very important.

by Bryan Gardiner / photograph by The Voorhes FOR ANOTHER (ACTUAL-SIZE) SMALL WONDER, SEE PAGE 36