Get a willow tree to draw you a picture

The Basic Idea

On a windy day, find a willow tree that reaches the ground and carefully attach pens to the branches with twine, being careful not to take off any of the leaves or damage the branches. Place a large piece of plain paper underneath. After 30 mins, the wind will have blown the branches & pens around, drawing a picture. Did you think the branches would move around more or less than they did? How many different directions did the branches move in?