String or Elastic Shapes
Lesson Plan
Years: 2 - 8 Time: 1 - 3 lessons
Summary:
Imagine 4 students in a group with a long brightly coloured loop of string. The group is asked to form the string into a square. Having made what they think is a square; the challenge is to devise a test to see if they have indeed made what they think they have. This physical or kinaesthetic involvement sets the scene for learning the properties and names of a series of geometric shapes in an atmosphere of co-operative, small group, problem solving. The lesson is suitable for several grade and ability levels.
Resources required:
· About 20m of brightly coloured wool, tape, elastic, string or twine for each group of 6. Choose the string so it contrasts with the background you will use. Bright yellow or red tends to contrast with most backgrounds.
· For each group, a set of polygon sheets. These may be used as reference cards as described in the lesson, or as a booklet the children take outside with them.
· A board or book and spring clip to secure each groups sheets outside.
Content Outcomes\Links To Curriculum Documents
· informal measurement
· classification of triangles
· properties of triangles
· classification of quadrilaterals
· properties of quadrilaterals, especially squares
· properties of other polygons
· symmetry
Lesson Stages
1. Quickly make some string triangles outside in groups.
2. Challenge the students to make an equilateral triangle and find a test for its 'equilateralness'.
3. Enlarge the challenge to make other shapes and develop further tests.
4. Follow up discussion.
5. Conclusion and extension possibilities.
Getting Started
Take one loop of string and ask three students to form it into a triangle.
Now make a different triangle ... and now another.
Now a long thin triangle and one where two sides are the same length.
This first part shows the efficiency of the activity - it takes just one or two minutes to demonstrate about 5 or 6 different types of triangles.
Lowering the shape to the ground while holding the corners 'tightly' gave everyone a nice 'birds eye view' of the shape.
Now can you make that special triangle where all sides are the same length?
Now comes the first problem solving challenge. Can the students invent a way of showing the lengths are all the same?
Provide a loop for each group of six and encourage students to explore.
When appropriate, gather under a tree for discussion of the tests. Hand out the Polygon Pages you have chosen and ask students to record the key points of the discussion.
ESL Comment: The words to go with the various triangles are introduced informally – but the chance of them being remembered and connected to the shape is much greater because the students are physically 'part' of the triangle.
The Challenge
Challenge the groups to make the other shapes in your particular Poly Plug pages booklet. Emphasise that the challenge is to devise for each case a test which demonstrates that the shape is what it purports to be.
Working the Data
At times, take the opportunity to return to the tree with some or all of the class to discuss their tests and encourage recording of key learning.
Conclusion & Extensions
1. Use 9 pin geoboards and challenge the students to see which of the shapes in their Polygon Pages booklet can be made on this board. This will soon bring forward discussion related to the angles which can and can't be made on this board. By so doing, the properties of the shapes are re-examined and learning extends.
2. Try using a 16 or 25 pin geoboard for the same purpose. Is there any size square geoboard on which you could make an equilateral triangle?
We regularly made some shapes every couple of lessons for a while. Revisiting the shapes was worthwhile because I noticed they became more accurate when making the shapes 'by eye' before testing them.
Polygon Pages
This page links to a collection of large polygon drawings. Select and print sufficient to make a booklet for the students to take outside with them. One booklet per group is sufficient.
You can construct the booklet to match your particular content objectives. For example, you may wish to:
· investigate triangles
· investigate quadrilaterals
· explore the angles of regular polygons
· introduce a language term like scalene or isosceles in context and include a counter example
The available polygons are:
Triangle (scalene) Triangle (right angle)
Triangle (isosceles) Triangle (equilateral)
Quadrilateral (scalene) Rectangle
Square Parallelogram
Rhombus Trapezium (isosceles)
Kite Pentagon (scalene)
Pentagon (regular) Hexagon (scalene)
Hexagon (regular)
Triangle (scalene)