In this project we are gonna build a laser show using diffraction and lasers.
Step 1: Get the Materials
you are going to need a linear diffraction grating (can be bought online), a short PVC pipe or cardboard toilet paper roll, a powerful laser (not a cheap $1 one), a wire clothes hanger (or any other thing that can hold the tube while it spins), pliers, a programmable lego motor set or slow-turning motor, a cup, a fog machine and tape.
Step 2: Diffraction Grating
take the Diffraction grating and shine the laser through it, there should be two extra dots that show up on the other side of the grating. Test this out before you start.
Step 3: The Tube
Take the PVC pipe or empty toilet paper roll and refine it to use for the project.
Step 4: The Main Spinner
Now using tape or a glue gun, mount the diffraction grating on to the end of the tube.
Step 5: The Holder (material)
Now find the wire clothes hanger and prep it for the project.
Step 6: You Can Use Other Materials for the Holder
The purpose of the clothes hanger is to hold the tube as it spins, if you don't have a clothes hanger you can also make something out of wood or plastic that can hold the tube while it spins. You want something that cause the least amount of friction so it will spin with ease.
Step 7: The Holder
If you do not use any other item to make the holder, you can use the wire hanger. Using pliers unwind the hanger to a straight line and cut it into equal halves.Bend the wire using the pliers so that there are two equal stands with a U-shape in the center. The purpose of this is to hold the tube. You may want to keep the stands taped down so they want fall over.
Step 8: The Laser
Now take the laser pointer and mount it on a plastic cup with tape so it directly goes through the open end of the tube and hits the center of the diffraction grating.
Step 9: Motors
Now use the motors that are programmed from the Lego kit or a separate slow-turning motor and put it against the tube, so the tube slowly rotates. This will require some toying around. You can make wheels or turning treads from the legos that turn and spin the tube.
Step 10: Sit Back
Now that everything is aligned perfectly, start the motor and let the tube turn! If you can't get the motor to properly turn the tube, just manually turn it!
Step 11: And Enjoy!
As the tube turns you will see the three different dots spinning in a circle with relation to the main laser dot. To get the full effect, you must use this laser show in the complete dark so you can see the laser beam. If you do not want to do that you can use a fog machine so you can see the actual laser beam and there will be a cool laser show effect. You can also add another stationery diffracting lens right in front of the turning one for really cool effects. Now all you have to do is sit back, play some cool music and enjoy.