In this paper we describe a simple alternative to the telephone book friction experiment, a classic demonstration where a small force (generated for example by the bending of the outer pages) is amplified by the large number of surfaces in contact, resulting in a huge maximum static friction force that has to be counterbalanced in order to separate the books. The aim of our experiment is to illustrate the friction force in a dramatic way and to simplify the tedious job of interleaving a large number of book pages, by using the minimum number of sheets necessary to sustain the weight of a person using the normal force produced by their fingers.

1.
Elena
Popova
and
Valentin L.
Popov
, “
The research works of Coulomb and Amontons and generalized laws of friction
,”
Friction
3
(
2
),
183
190
(
2015
).
2.
Charles Augustin
Coulomb
,
Theorie des Machines Simples: En ayant egard au frottement de leurs parties et a la roideur des cordages
(
Bachelier
,
1821
), obtained from http://books.google.fr/books?id = zGYSAAAAIAAJ.
3.
Michio
Otsuki
and
Hiroshi
Matsukawa
, “
Systematic breakdown of Amontons’ law of friction for an elastic object locally obeying Amontons’ law
,”
Sci. Rep.
3
,
1586
(
2013
).
4.
Oded
Ben-David
and
Jay
Fineberg
, “
Static friction coefficient is not a material constant
,”
Phys. Rev. Lett.
106
,
254301
(
2011
).
5.
David
Van Domelen
, “
Showing area matters: A work of friction
,”
Phys. Teach.
48
,
28
(
Jan
.
2010
).
6.
Evan
Jones
, “
Amontons’ laws
,”
Phys. Teach.
48
,
564
(
Dec
.
2010
).
7.
Nuri
Balta
and
Ali
Çetin
, “
Inseparable phone books demonstration
,”
Phys. Educ.
52
,
035006
(
2017
).
9.
Kari
Dalnoki-Veress
,
Thomas
Salez
, and
Frédéric
Restagno
, “
Why can’t you separate interleaved books?
Phys. Today
69
(
6
),
74
(
2016
).
10.
Hector
Alarcon
 et al, “
Self-amplication of solid friction in interleaved assemblies
,”
Phys. Rev. Lett.
116
,
015502
(
2016
).
11.
Coefficients of Static and Kinetic Friction of Uncoated Writing and Printing Paper by Use of the Horizontal Plane Method
,” http://www.tappi.org/content/tag/sarg/t549.pdf.
12.
Ben
Finio
, “
Phone book friction
,”
Sci. Am.
(
Oct.
22,
2015
), https://www.scienticamerican.com/article/phone-book-friction/.
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.