The Physics Teacher's “iPhysicsLabs” column has been dedicated to the implementation of smartphones in instructional physics labs as data collection devices. In order to understand any data set, however, one should first understand how it is obtained. This concern regarding the inclusion of smartphones in lab activities has arisen in response to the creation of this column1 as well as to a paper in a recent issue of Physics Today.2 The majority of the labs featured in the “iPhysicsLabs” column to date make use of the internal accelerometer, common to nearly all smartphones on the market today. In order to glean meaningful conclusions from their data, students should first understand how the sensor works, as was pointed out in the first article to be featured in that column.3 We attempt to elucidate this “iBlackBox” using a simple ball-and-spring model.

1.
J.
Hall
, “
iBlackBox?
Phys. Teach.
50
(
5
),
260
(
May 2012
).
2.
L.
Kowalski
, “
Passive learning in the electronic age
,”
Phys. Today
66
(
10
),
8
(
2013
).
3.
P.
Vogt
and
J.
Kuhn
, “
Analyzing free fall with a smartphone acceleration sensor
,”
Phys. Teach.
50
(
3
),
182
(
March 2012
).
4.
B.
Thomas
,
SensorLog
,
2011
. Retrieved from https://itunes.apple.com/us/app/sensorlog/id388014573?mt=8.
5.
6.
PASCO
,
SPARKvue
,
2012
. Retrieved from https://itunes.apple.com/us/app/sparkvue/id361907181?mt=8.
7.
Proof masses are often composed of silicon. A similar accelerometer's plates were driven by 1-MHz square waves.
M.
Andrejasic
and
I.
Poberaj
, “
MEMS Accelerometers
” (
2008
), pp.
1
17
. Retrieved from http://mafija.fmf.uni-lj.si/seminar/files/2007_2008/MEMS_accelerometers-koncna.pdf.
8.
B.
Hammack
,
P.
Ryan
, and
N.
Ziech
,
Eight Amazing Engineering Stories: Using the Elements to Create Extraordinary Technologies
(
Articulate Noise Books
,
2012
), pp.
23
38
.
10.
T. M.
Kalotas
and
B. G.
Wybourne
, “
An application of the equivalence principle in classical mechanics
,”
Eur. J. Phys.
2
(
1
),
52
54
(
1981
).
11.
P.
Vogt
and
J.
Kuhn
, “
Analyzing simple pendulum phenomena with a smartphone acceleration sensor
,”
Phys. Teach.
50
(
7
),
439
(
Oct. 2012
).
AAPT members receive access to The Physics Teacher and the American Journal of Physics as a member benefit. To learn more about this member benefit and becoming an AAPT member, visit the Joining AAPT page.