Owing to the presence of the Coriolis effect, the rotation of Earth has a multitude of surprising consequences that make the mechanics of the atmosphere or the oceans different from that of a fluid in a container. Since the Coriolis effect also captures the imagination of screenwriters, contributing to the continual exposure of students to bogus science, it is important to address these ideas in the physics classroom. This paper assumes that students are familiar with the Coriolis force acting on moving bodies in a rotating reference frame, and suggests a possible algebra-based approach. The information encoded in pressure maps is used to obtain wind velocity, and the result is applied in various contexts to learn about tilting sea surfaces, northern lights, and fluids flowing around phantom obstacles.

1.
J.
Higbie
, “
Simplified approach to Coriolis effects
,”
Phys. Teach.
18
,
459
460
(
Sept.
1980
).
2.
Alpha E.
Wilson
, “
Jogging on a carousel
,”
Phys. Teach.
49
,
570
571
(
Dec.
2011
).
3.
Ned
Mayo
, “
A hurricane for physics students
,”
Phys. Teach.
32
,
148
154
(
March
1994
).
4.
Amit
Tandon
and
John
Marshall
, “
Einstein’s tea leaves and pressure systems in the atmosphere
,”
Phys. Teach.
48
,
96
99
(
Feb.
2010
).
5.
Richard M.
Heavers
and
Rachel M.
Dapp
, “
The Ekman layer and why tea leaves go to the center of the cup
,”
Phys. Teach.
48
,
292
295
(
May
2010
).
7.
The scale devised by Admiral Sir Francis Beaufort of the British Navy in 1806 is still used in marine forecasts. The scale is based on the visible effects of wind. For example at a level 6 on the Beaufort scale, larger branches of trees are moving and umbrellas become unwieldy.
8.
The equilibrium consideration is only valid if the moving air is not making sharp turns. The meaning of a “sharp turn,” however, is not obvious at all. For example, in order to refute the myth of the plughole, we need to show that the draining water is, indeed, making a sharp turn, which involves an inward net force several orders of magnitude greater than the Coriolis force. The use of algebra alone will not reveal that: it is necessary to compare acceleration components numerically.
9.
Strictly speaking, the friction (viscous) force influencing the motion of the lowermost layers of the atmospere of the rotating Earth is only approximately antiparallel to the velocity. It actually points at right angles to the difference of the wind velocity vectors corresponding to the two panels of Fig. 2. For a rigorous explanation involving vector calculus, see, for example, Pijush K. Kundu, Ira M. Cohen, and David R. Dowling, Geophysical Fluid Dynamics (Elsevier, 2012), p. 641.
11.
See weatheronline.co.uk, height 500 hPa ECMWF (gpdm) Sun 29/07/18 00UTC (Fri 00+48).
12.
If we wish to stick with isobars instead of considering the topography of pressure surfaces, we can say that in an isobar chart of a little higher altitude, the very same curves are drawn on the map, but each curve will bear a pressure label reduced by the exact same amount. Thus the pressure change per unit horizontal distance will remain the same as at a lower level, and therefore —since density is uniform—the horizontal velocity will also be the same.
13.
Aurora Borealis Explained
,” YouTube, www.youtube.com/watch?v=1DXHE4kt3Fw.
14.
I.
Janosi
and
T.
Tel
,
Introduction into Environmental Flows
(
Typotex
,
Budapest
,
2012
, in Hungarian), p.
109
.
16.
Google Earth.
17.
Seelye
Martin
and
Robert
Drucker
, “
The effect of possible Taylor columns on the summer ice retreat in the Chukchi Sea
,”
J. Geophys. Res.
102
(
C5
), 10,
473
10
, 482 (
May
1997
).
18.
Jin-Ping
Zhao
,
Jiu-Xin
Shu
,
M.
Jin
,
Chaolun
Li
,
Yu-Tian
Jiao
, and
Yong
Lu
, “
Water mass structure of the Chukchi Sea during ice melting period in the Summer of 1999
,”
Adv. Earth Sci.
25
,
154
162
(
Feb.
2010
).
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.