Hello, we are Swathi and Gayatri, we are from Kagallipura Project DEFY nook.
Step 1: Make a Hole on the Cap
Make a hole exactly at the center of water bottle cap with the help of push drill which is as shown in the image.
Step 2: Insert Balloon to Sketch Pen
Make hole on sketch pen cap with help of push drill now insert a balloon on another end of sketch pen with the help of rubber band which is as shown in the image.
Step 3: Assembling
Now put some glue at the center of CD and stick water bottle cap on that.
Now insert sketch pen cap inside the hole of water bottle cap, and put some glue now let it to set up for some time. Now blow the balloon and insert it to water bottle cap then put it on the smooth surface now you can observe that the moving CD.