What is the definition of symmetry


This swallowtail butterfly can lay its wings exactly on top of one another because they are axially symmetrical.

Whoever stands in front of a mirror sees his own body in it. The original and the mirror image are called mirror-inverted or symmetrical. Every object forms a symmetrical image in a mirror.

Man in himself is already a symmetrical figure. The left side is a mirror image of the right side. Of course, this is not entirely true in every detail. A face is usually a little one-sided. Roughly speaking, one speaks of symmetry in this case.

In some animals the symmetry is quite obvious, for example in the butterfly. In one photo you could find a line that divides the butterfly into two equal halves. You could fold the paper along this line so that both halves of the figure fit together exactly. They are therefore called congruent. The fold line is called the axis of symmetry.

Many technical things, for example airplanes, are almost perfectly axially symmetrical. If an airplane were not axially symmetrical, it would not be able to fly properly. There are also houses or castles that are built exactly axially symmetrical.

Are there other types of symmetries?

Some figures can be turned, and in certain positions they always look the same. The best example is the wind turbine. You can turn it one wing without noticing a difference. So the pictures are congruent. This is called rotational symmetry.

There are also point-symmetrical figures, for example the rhombus. You can mirror it at its center. So it looks exactly the same again.

Playing cards are particularly interesting. Some are axially symmetrical. Others are rotationally symmetrical and at the same time point symmetrical. It's best to try it out yourself.

  • This wind chime is rotationally symmetrical and point symmetrical.

  • This wind chime is rotationally symmetrical, but not point symmetrical.

  • The king on this playing card is also rotationally symmetrical.

  • This rhombus can be reflected not only at its diagonals, but also at its center. That is a point symmetry.

There are also other search results for "Symmetry" from Blinde Kuh and Ask Finn.

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