A laser (light amplification by stimulated emission of radiation) is a coherent beam of man-made light that does not occur naturally. You can make a laser that will function identically to a laser pointer purchased at a store. A common battery powered flashlight and a CD player are all that is needed, along with some hardware tools and a laser module from an electronics supply shop. Adult supervision is required if the person making the laser is underage, since a soldering iron must also be used.
Put newspaper down on a table. Unscrew the reflector from the flashlight. Discard the plastic lens that is inside of the reflector. Remove the retaining ring from around the front end of the flashlight.
Pull the incandescent bulb module out of the front end of the flashlight with the tweezers.
Remove the battery cap from the back end of the flashlight. Remove the batteries.
Unplug the CD player. Put the CD player on the newspaper. Remove the screws from the left and right side of the CD player with the Phillips screwdriver.
Lift up on both sides of the outer case of the CD player with your hands. Pull the outer case up.
Pull the CD tray out of the front of the CD player. Remove the outer case from off of the CD player.
Locate the black, circular spindle hub inside of the CD player. Insert the tip of the Phillips screwdriver beneath one side of the laser module that is directly over the spindle hub.
Wiggle the tip of the Phillips screwdriver to dislodge the side of the laser module from the rail it is riding on. Repeat this process on the other side of the laser module.
Pull the laser module off of the two rails with your fingers. Put the laser module down on the newspaper.
Remove the screw from the bracket on the top of the laser module with the Phillips jeweller's screwdriver. Remove the bracket with your fingers.
Pull the laser diode that was underneath the bracket out of the laser module with the tweezers. Put the laser diode down on the newspaper.
Unscrew the laser module with your hands. Discard the empty front half of the laser module.
Pull the laser housing from out of the back half of the laser module with the tweezers. Discard the back half of the laser module.
Insert the two pins of the laser diode into the positive-labelled and negative-labelled holes in the laser housing.
Solder the two conductive pins to the back of the laser housing, corresponding to the positive-labelled and negative-labelled holes. Let the solder cool for a minute.
Insert the laser housing, conductive pins first, into the front end of the flashlight.
Put the retaining ring back onto the front end of the flashlight. Screw the reflector back onto the front end of the flashlight.
Put the batteries back into the back end of the flashlight. Replace the battery cap.
Aim the flashlight at a far wall. Depress the "On" button on the flashlight to see a beam of laser light projected onto the far wall.
You can make a more powerful laser by using a green laser diode or a blue-violet laser diode, instead of the one that was in the CD player.
Never aim the beam of a laser at a person's face -- the laser beam can hurt the retina of the eyes.