How to Make a Cardboard Wind Vane That Spins Freely

Wind vanes come in a wide variety of shapes and designs.

Wind vanes have a long history of determining wind direction and wind shifting. Wind vanes accurately point in the direction of wind flow, since they use a flattened pointer head and tail that creates resistance to oncoming wind pressure. Simply following the opposite direction of the pointer in a straight line with the tail section, the source of the wind direction can be deduced. An ordinary craftsman with a few tools and supplies can produce a cardboard wind van that will serve as an accurate directional wind meter.

Things You'll Need

• Thin cardboard stock
• Pencil
• Ruler
• Straw
• Scissors
• Cellophane tape
• Hat pin
• Pencil
• Fan (optional)

Instructions

1. Lay out a thin piece of cardboard stock on the flat table surface. Use a pencil and ruler to draw the image of a pointer on the cardboard stock that resembles an equilateral triangle. Make note of the length and thickness of the pointer image. Draw the image of a tail fin on the cardboard stock that has the same width, but is twice as long as the pointer. Give the tail fin a triangular head and a concave triangular rear section. Use the ruler for straight lines.

2. Cut out the pointer and tail fin with scissors, being careful not to bend the cardboard. Obtain a long plastic straw, the thicker the better. Use scissors to cut a slit in the middle of each end of the straw, about 1 inch in length. Slip one end of the straw over the backside of the pointer, positioning it in the middle of the pointer, and tape it on both sides with cellophane tape.

3. Slip the other end of the straw over the tail fin, positioning it in the middle of the front (pointing) side. Tape the straw to the tail fin on both sides, making sure it sits horizontally straight. Balance the straw over your finger tip to find its center of gravity, then mark that position with the pencil.

4. Stab a hat pin into the straw, where you marked the gravity point with the pencil. Stick the hatpin into the top of a pencil eraser, and check the balance. If you need to, remove the hatpin and reposition it in the straw to achieve the correct balance. Make sure the straw does not rest on the eraser's surface and that it spins freely through 360 degrees of rotation.

5. Stick the pencil in the ground outside, or support it in a vertical position on top of a table. For an interior demonstration, turn on a fan and watch the vane align, showing the wind direction. Move the fan around the wind vane from different positions and note how the vane adjusts to the wind pressure and changes direction. For an outside demonstration, shove the pencil in the ground and simply note the direction of the wind vane and any turns it makes as a result of wind shifts.

References

• Problem Solver: Homemade Wind Vane