• Thin cardboard or heavy card stock
• One plastic or paper straw (to use as a handle)
• One brass fastener (brad)
• Scissors
• A ruler or measuring tape
• A marker or pen

1. Cut out the wheel: Draw a perfect circle on your cardboard and cut it out with scissors. (Tip: A circle with a diameter of about 7 inches or 19 cm works great for a manageable wheel).
2. Find and punch the center: Locate the exact center of your cardboard circle. Poke a small hole through it using the tip of your scissors or a pencil.
3. Prep the handle: Take your straw and punch a hole through one end, about half an inch from the tip.
4. Assemble the wheel: Push the brass fastener through the center hole of your cardboard wheel first, and then through the hole in your straw.
5. Secure the fastener: Open up the legs of the brass fastener on the back side of the straw. Keep it loose enough so that the cardboard wheel can spin freely when you roll it.
6. Mark your starting point: Use a marker to draw a straight line from the center of the wheel to the outer edge. This is what you will use to count your rotations.

• Line up your starting mark with the beginning of the distance you want to measure.
• Roll the wheel along the floor in a straight line.
• Count how many times the mark makes a full rotation and hits the ground again.

The distance measured will be how many times your wheel turned multiplied by the circumference of your circle (the measure around it).

(source)