Originally an empirical law, nowadays Malus’ law is seen as a key experiment to demonstrate the transverse nature of electromagnetic waves, as well as the intrinsic connection between optics and electromagnetism. In this work, a simple and inexpensive setup is proposed to quantitatively verify the nature of polarized light. A flat computer screen serves as a source of linear polarized light and a smartphone (possessing ambient light and orientation sensors) is used, thanks to its built-in sensors, to experiment with polarized light and verify Malus’ law.

1.
L. P.
Vieira
,
V. O. M.
Lara
, and
D. F.
Amaral
, “
Demonstração da lei do inverso do quadrado com o auxílo de um tablet/smartphone
,”
Revista Brasileira de Ensino de Física
36
(
3
),
3505
(
2014
).
2.
J. A.
Sans
,
F. J.
Manjón
,
A. L. J.
Pereira
,
J. A.
Gómez-Tejedor
, and
J. A.
Monsoriu
, “
Oscillations studied with the smartphone ambient light sensor
,”
Eur. J. Phys.
34
(
6
),
1349
(
2013
).
3.
Sanford C.
Gladden
, “
An experiment on Malus’ law for the elementary laboratory
,”
Am. J. Phys.
18
,
395
(
June
1950
).
4.
Thomas M.
Ciferno
,
Renate J.
Ondris-Crawford
, and
Gregory P.
Crawford
, “
Inexpensive electrooptic experiments on liquid crystal displays
,”
Phys. Teach.
33
,
104
110
(
Feb.
1995
).
5.
H.
Fakhruddin
, “
Some activities with polarized light from a laptop LCD screen
,”
Phys. Teach.
46
,
229
231
(
April
2008
).
6.
Larissa
Vertchenko
and
Lev
Vertchenko
, “
Verification of Malus’s law using a LCD monitor and digital photography
,”
Revista Brasileira de Ensino de Física
38
(
3
),
e3311
(
2016
).
7.
H.
Gottlieb
, “
The law of Malus using polaroid polarizers
,”
Phys. Teach.
18
,
612
614
(
Nov.
1980
).
8.
M. A.
Dias Tavares
 Jr.
,
L. P.
Sosman
,
R. J. M.
da Fonseca
,
L. A. C. P.
da Mota
, and
M.
Muramatsu
Using a photo-resistor to verify irradiance inverse square and Malus’ laws
,”
AIP Conf. Proc.
992
,
193
198
(
2008
).
9.
M.
Kutzner
,
R.
Wright
, and
E.
Kutzner
, “
An inexpensive LED light sensor
,”
Phys. Teach.
48
,
341
(
May
2010
).
10.
M.
Monteiro
,
C.
Cabeza
,
A. C.
Martí
,
P.
Vogt
, and
J.
Kuhn
, “
Angular velocity and centripetal acceleration relationship
,”
Phys. Teach.
52
,
312
313
(
May
2014
).
11.
M.
Monteiro
,
C.
Cabeza
, and
A. C.
Martí
, “
Exploring phase space using smartphone acceleration and rotation sensors simultaneously
,”
Eur. J. Phys.
35
(
4
),
045013
(
2014
).
12.
M.
Monteiro
,
C.
Cabeza
, and
A. C.
Martí
, “
Acceleration measurements using smartphone sensors: Dealing with the equivalence principle
,”
Revista Brasileira Ensino de Física
37
(
1
),
1303
(
2015
).
13.
M.
Monteiro
,
P.
Vogt
,
C.
Stari
,
C.
Cabeza
, and
A. C.
Martí
, “
Exploring the atmosphere using smartphones
,”
Phys. Teach.
54
,
308
(
May
2016
).
14.
E.
Hecht
,
Optics
(
Addison-Wesley
,
1998
).
15.
It is called a pseudo-sensor because it does not measure directly the inclination but obtains it based on algorithms using the information from the built-in accelerometer, magnetometer, and, eventually, the gyroscope.
16.
17.
P.
Velasquez
,
M.
del Mar Sánchez-López
,
I.
Moreno
,
D.
Puerto
, and
F.
Mateos
, “
Interference birefringent filters fabricated with low cost commercial polymers
,”
Am. J. Phys.
73
,
357
(
April
2005
).
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.