Question

Many smartphones have an inbuilt accelerometer that can detect very small accelerations. Install an app, such as Phyphox (phyphox.org) and open ‘Accelerometer’ (without g). Note the readings when (i) the phone is on an outstretched palm, and (ii) the phone is kept on the floor. What differences do you observe? What does this tell you about motion and acceleration in real situations? (Such tiny, involuntary movements are also studied in medical research, for example, in movement disorders) This activity is recommended to be performed as a classroom group activity facilitated by teacher.

Answer 1

Observation:

1. Phone on an outstretched palm: The accelerometer readings fluctuate slightly because your hand is never perfectly still. Tiny involuntary muscle movements and slight body sway cause small changes in acceleration.
2. Phone kept on the floor: The readings remain almost constant with very little variation, as the phone is at rest on a stable surface.

This activity shows that in real life, it is difficult to keep an object completely motionless when it is held by hand. Even when we think we are still, our bodies make tiny involuntary movements that produce small accelerations. A sensitive accelerometer can detect these minute changes, whereas an object placed on a stable surface experiences almost no such acceleration.