This article presents numerous examples of an erroneous conception, stating that the “total force” by which a fluid acts on an immersed body is equal to the product of corresponding fluid pressure and the body’s surface area. This conception, which started its long life at the beginning of XVIII century, still appears in today’s physics textbooks published in different countries for different educational levels. It is formulated either as an “astonishing fact” or should be “discovered” through students’ calculations. In the last case, students’ knowledge may be unnecessary fragmented. Finally, a few differences between cultures of school and research physics are shortly discussed.