You will need: scissors, a ruler, construction paper, a drinking straw, a straight pin, and a pencil.
Cut a triangle with 2″ (5 cm) sides from the construction paper.
Cut a 1/2″ (15 mm) slit in the end of a drinking straw, and insert the middle of one side of the triangle into it to make a pointer arrow (see illustration).
Push a straight pin through the center of the side of the straw, down into the pencil eraser (see illustration).
Hold the weathervane in the air or stick the pencil into the ground. The weathervane will show you which way the wind is blowing.