How to Make a Wind Measurer

Select four paper or plastic cups of the same size and model. Use scissors to cut off the expanded rims of the cups to reduce their weight. Use a marker to color one of the cups differently than the others.

Cut two equally sized rectangular pieces of corrugated cardboard -- 3-inch x 12-inch strips are sufficiently long without being too heavy. Place them into a perpendicular "X" shape and use a ruler to verify that each arm is the same length from the center. Staple the two pieces together.

Staple a cup to the end of each arm -- make sure the openings of the cups all face the same direction (all clockwise or all counterclockwise).

Use a straightedge and a pencil to draw diagonal lines between the corners of where the cardboard strips come together -- this will determine the center of the cardboard construct. Insert a push pin through the cardboard where the two lines intersect.

Secure the anemometer by inserting the end of the pin into the eraser end of the pencil. Check the anemometer's freedom of movement by rotating the cups by hand or by blowing into them -- if the rotation is sluggish, then wiggle the pin around in the cardboard to slightly enlarge the hole.

Find a location that is exposed to the wind on all sides -- avoid low-lying areas and areas near walls or other objects that could obstruct the wind. Place a lump of modeling clay on a hard and secure surface (such as a rock or a block of wood) and insert the pencil point-first into the clay. Make sure that the anemometer is standing up straight and then wrap the clay tightly around the pencil to keep it secure.

Keep an eye on the colored cup and count the number of complete rotations that occur in one minute. Multiply the number of rotations by 0.2142 to obtain a rough estimate of the wind speed in miles per hour.