introduction to types of symmetry
DESCRIPTION
Introduction to Types of Symmetry. Symmetry. Symmetry - part of a design that is repeated to make a balanced pattern. Artists use symmetry to make designs that are pleasing to the eye. Architects use symmetry to produce a sense of balance in their buildings. - PowerPoint PPT PresentationTRANSCRIPT
INTRODUCTIO
N TO TY
PES
OF SYM
METRY
SYMMETRYSymmetry - part of a design that is
repeated to make a balanced pattern.Artists use symmetry to make designs that are
pleasing to the eye.Architects use symmetry to produce a sense of
balance in their buildings.Symmetry is a feature of animals, plants, and
mechanical objects.
1. How might these three pictures earn the label that they have symmetry?
2. What kinds of symmetry are represented in each picture?
REFLECTION SYMMETRYHave you ever made a simple
heart shape by folding and cutting paper?
The heart is made by using reflection symmetry.
Reflection symmetry is the SAME thing as line symmetry.
If you place a mirror on the line of symmetry you will see half of the figure reflected in the mirror.
DO YOU NOTICE LINE SYMMETRY IN NATURE?
DETERMINE IF THE OBJECT HAS LINE SYMMETRY. IF SO, DRAW ALL OF THE
LINES OF SYMMETRY.
3 Lines of Symmetry
DETERMINE IF THE OBJECT HAS LINE SYMMETRY. IF SO, DRAW ALL OF THE
LINES OF SYMMETRY.
4 lines of symmetry
DETERMINE IF THE OBJECT HAS LINE SYMMETRY. IF SO, DRAW ALL OF THE
LINES OF SYMMETRY.
No lines of symmetry.
Does this picture have line symmetry?What kind of symmetry does it have?
Rotational Symmetry: A figure has rotational symmetry when it can be turned less than a full turn around its center point in which it looks the same as it does in its original position.
The Center of Rotation is a fixed point about which you rotate the figure.
The Angle of Rotation is the smallest angle through which you can turn the figure so that it looks the same as it does in the original position.
HOW DO YOU FIND THE ANGLE OF ROTATION?
1.Determine if the figure has rotational symmetry.
2.Count how many partial turns you can do to the figure where the figure lines up on itself.
3.Divide 360˚ by that number.
1
2
3
4
For this shape divide 360˚ by 4.The answer is 90˚.The first rotation is 90˚, the second is 180˚, the third is 270˚ and the fourth is 360˚.
Does this figure have Rotational Symmetry?
What is the first angle of rotation?
180˚
Does this figure have Rotational Symmetry?
What the first angle of rotation?
30˚
Does this figure have Rotational Symmetry?
No rotational symmetry
Does this figure have Rotational Symmetry?
What the first angle of rotation?
120˚