How to Build Your Own Laser Science Fair Project

By Marshal M. Rosenthal

Scientists call it “Light Amplification by the Stimulated Emission of Radiation,” but we know a beam of light not known to nature by the acronym “laser.” This powerful beam of light can produce intense heat at close range and is used in creating medicine and for microsurgery among other applications. Building your own laser for a science project enables you to display the properties of a laser light close up using a few electronics parts and the laser diode and power supply from a green laser pointer. The laser that you will build will be powerful enough to burn a piece of cardboard at close range.

Things You'll Need

  • Green laser pointer
  • Soldering iron
  • Microswitch
  • Conductive pins
  • Tweezers
  • Needle nosed pliers
  • Cardboard
  • Utility knife
  • Duct tape
  • White glue
  • Electric wire
  • Wire strippers
  • Wire cutter
  • Black magic marker
  • Colored crayons
  • Spray bottle

Step 1

Put the newspaper down on a table. Put the cardboard down on the newspaper. Cut a rectangle out of the cardboard using the utility knife. Cut a smaller rectangle out of the cardboard with the utility knife. Attach the smaller rectangle to the back of the larger rectangle of cardboard with duct tape. Use the black magic marker to draw a space satellite on the side of the large rectangle of cardboard that does not have the small rectangle of cardboard duct taped to it. Color in the picture of the satellite with the crayons.

Step 2

Put the newspaper down on the work surface. Remove the battery cap and the batteries from the laser pointer and put them aside. Grip the green laser pointer at each end and twist till the center seam cracks. Grip the front half of the laser pointer with the needle nosed pliers and twist it off of the back half.

Step 3

Use the needle nosed pliers to pull the laser assembly out of the back half. Put the laser assembly down on the newspaper. Heat up the soldering iron. Apply the tip of the soldering iron to the small circuit board that is above the silver screw on the laser assembly. Remove the soldering iron after 10 seconds. Insert the flat-edged jeweler's screwdriver into the screw on the laser assembly and turn it one-quarter of a turn counter-clockwise.

Step 4

Solder one conductive pin each to the two battery contacts at the back of the laser assembly. Let the solder cool. Cut two strips of 6-inch long electric wire using the wire cutters. Strip the insulation off of both ends of the two wires with the wire strippers. Solder the end of one wire to one of the conductive pins. Solder the other end of the wire to one of the two contacts on the microswitch. Solder the end of another wire to the other contact on the microswitch. Solder another wire to the other conductive pin on the laser assembly.

Step 5

Solder the free end of the wire attached to one of the conductive pins to the battery contact inside of the back half of the green laser pointer. Solder the free end of the wire connected to the microswitch to the other battery contact inside of the back half of the green laser pointer.

Step 6

Use the white glue to glue the laser assembly to the ruler. with the laser diode slightly overlapping the end of the ruler. Glue the microswitch to the center of the ruler. Glue the back half of the green laser pointer to the other end of the ruler.

Step 7

Put the batteries back into the back half and close the battery compartment. Fill the spray bottle with tap water and place it nearby.

Step 8

Pick up the ruler and aim the powerful, burning laser you have made at the cardboard standup from about a foot away. Flip the microswitch on and aim the beam of green laser light on the cardboard standup. Move the ruler closer to the cardboard standup until the beam of laser light starts to burn a hole in the cardboard standup. Flip the microswitch to turn off the laser as soon as the beam of green laser light starts to burn a hole in the cardboard standup. Spray water on the cardboard standup with the spray bottle to extinguish the fire.

Tips & Warnings

  • Take digital photos as you build the laser and assemble them into a slide presentation that can run on a portable DVD player alongside of the laser. This will provide details on how the laser was made as well as allowing you to add diagrams on how a laser works.
  • Do not ever aim a laser at a person under any circumstances whatsoever.
  • Wear protective eyeglasses when demonstrating the burning power of the green laser you have made.