Draw dots on the spiraled seam of the tube using the marker. Place each dot about a half inch apart.
Insert a nail into each dot.
Wrap your packing tape around the tube so that you're securing the nails to the tube.
Cut circles out of the paper large enough to cover each end of the tube. Place one of the circular pieces of paper over one end of the tube and use the packing tape to keep it in place.
Grab a handful of the uncooked rice and place it inside the open end of the tube.
Add the other circular piece of paper to the open end of the tube and use the packing tape to keep it in place.
Flip the rain stick over repeatedly. The rice crashing against the nails inside the tube will create a rain sound effect.