Task
In the classroom, you will need paper, adhesive putty such as Blu Tack, some string and two pencils. If you can use a beach or sandpit you could do the exercise with two sticks and some string.
- You are going to use a pencil as a column to wind string around.
- Tack your sheet of paper to a table or board.
- Tie a piece of string to the blunt end of the first pencil with some tack to stop it slipping.
- Stand this pencil in the middle of your paper as a column, point upwards. Tack it in place at the bottom and ask someone to hold the point and keep it vertical.
- Tie the other end of the string to the point of the second pencil near the edge of your paper.
- Keeping the string taut, move the pencil around the column so that it begins to draw the spiral.
- Every time the string winds around the column your line will get closer to the centre. When you get to the middle you will have a complete spiral.
- You could try again with a thicker column (for example a marker pen or a piece of dowel) to see how the spiral changes.