This experiment uses the sound of each bounce to retrieve its timing and calculates the values by assuming that the ball loses the same portion of energy on each bounce.

Note, that there is a possibly confusing distinction between “Acceleration with g” and “Acceleration (without g)”. The sensor in your phone actually measures a force on a sample mass, which includes the contribution from gravitational acceleration. Therefore, this sensor will report the earth’s acceleration of 9.81 m/s² while the phone is resting (which is what we call “Acceleration with g”). In contrast, the physical acceleration is zero when the phone is resting (or moving at a constant speed), so most phones offer a virtual sensor which subtracts the constant acceleration (usually by taking into account the data from other sensors as well). This is what we call “Acceleration (without g)” and it will actually report an acceleration of zero while the phone is not accelerated.

Note, that there is a possibly confusing distinction between “Acceleration with g” and “Acceleration (without g)”. The sensor in your phone actually measures a force on a sample mass, which includes the contribution from gravitational acceleration. Therefore, this sensor will report the earth’s acceleration of 9.81 m/s² while the phone is resting (which is what we call “Acceleration with g”). In contrast, the physical acceleration is zero when the phone is resting (or moving at a constant speed), so most phones offer a virtual sensor which subtracts the constant acceleration (usually by taking into account the data from other sensors as well). This is what we call “Acceleration (without g)” and it will actually report an acceleration of zero while the phone is not accelerated.

An usage example is measuring the speed of sound or the duration of a free fall.