A Cartesian diver can be held suspended in a liquid in which there is a density gradient decreasing from bottom to the top if the density of the diver is between those of the liquid at the top and the bottom. This article adds to a number of Cartesian diver activities published in TPT.1 In a tall beaker of water, a large amount of sugar is added to the bottom. As the sugar dissolves at the bottom, a density gradient, decreasing from bottom to the top, is set up.

1.
See, for example,
Hasan
Fakhruddin
, “
Cartesian diver and riser
,”
Phys. Teach
41
,
53
(Jan.
2003
);
R. M.
Graham
, “
An extremely sensitive Cartesian diver
,”
Phys. Teach.
32
,
182
183
(March
1994
);
T.
Ragsdale
, “
Cartesian diver
,”
Phys. Teach.
27
,
306
(April
1989
);
R. B.
Knollenberg
III
, “
An automated Cartesian diver apparatus
,”
Phys. Teach.
27
,
51
(Jan.
1989
);
E. V.
Lee
, “
Cartesian diver with pressure head
,”
Phys. Teach.
19
,
416
(Sept.
1981
);
H.
Kruglak
, “
The rising Cartesian diver
,”
Phys. Teach.
13
,
68
69
(Feb.
1975
); and
R. N.
Jones
, “
The Cartesian diver
,”
Phys. Teach.
11
,
345
(Sept.
1973
).
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