This simple spinning wheel takes about 20 minutes to make, and can be shared with anyone over 4 years old. It can be used to teach lessons in physics and optics. It costs a few cents to make.
You start by putting a twist in the loop of string by twirling the wheel between your hands. Then you pull apart to get it spinning and release the pull, while continuing to support the system between your hands. Each time you pull apart, the wheel turns in the opposite direction, storing the energy in the wound string until you pull on it again to release the energy.
Once this wheel turns at 25 Hz, the colors will blend to form a solid colour. If you use two colors, red and blue, you will see purple. If you use the full spectrum such as here, you will see white. There will be a point where you will see a separation of colours, red green blue. This speed of rotation will be your threshold of perception of frequency. For most people it will be 25 Hz.
The attraction is that it is easy to make, and fun to use. Enjoy the spinning wheel.
Step 1: Bill of Materials and Tools Needed
I made mine from bits and pieces of scrap that were lying about.
Step 2: Draw Circles With the Compass
Set compass to 3cm and go for it.
Step 3: Make the Segments to Color in Equal
With a bit of interesting trigonometry you don't need a protractor here. Even the maths can be fun.
Step 4: Color It In
Coloring in is fun. Don't need to be too neat either. Colors of the rainbow are
The full color spectrum will produce a blended white surface. If you use just red and blue you will get purple. If you create a spiral, you will see a solid color at around 25Hz. The speed where you see the color is your perception threshold.
Step 5: Cut It Out and Glue It Together
Careful with the sharp scissors
Step 6: Thread the Needle and Pull the String Through.
Pierce the wheel about 3mm either side of centre, threading the string through and back. I made my string by twisting some cotton threads from an old spool of white cotton together.
Step 7: Knot the String to Form the Loop and Start Spinning
Put a knot in the string ends to make a loop. Put the wheel in the middle of the loop while held between your hands. Twirl it a few times until you have a twist in the string. Gently pull your hands apart so as to NOT BREAK THE STRING. When it starts to spin release your pull. The string will twist the opposite way. Pull again adding a little more force each time. The wheel will spin faster and faster with each pull and release. It has been a year since I made mine, and I still carry it in my pocket to show kids. Its important that we pass on these simple skills.