Home Show Overview Demonstrations Topics Covered Scheduling Info Feedback


The information below is intended to provide introductory material for elementary students and further material for high school students.

Please keep in mind that not all demonstrations are presented at each show, and each topic may not be covered.


LASERS

Introduction

  • Unlike normal light, which spreads in all directions, lasers are constructed so that a laser beam travels only in a straight line. A laser beam travels in a straight line until it collides with an object, then spreading in all directions like normal light.

    The invention of lasers was very important because it allowed scientists to concentrate light in a single beam. This provided scientists with many applications. Its properties also produce exciting effects. Since a laser beam travels in a straight line until a collision, a laser can not be seen until it collides with an object. The actual physics behind lasers is much too difficult for discussion here.


  • More Specifically

  • Unlike normal light, which spreads in all directions, lasers are constructed so that a laser beam travels only in a straight line. A laser beam travels in a straight line until it collides with a molecule which is large enough to interact with the light. Once the laser beam has collided with a large enough particle, it will reflect and spread in all directions like normal light.

    The invention of lasers was very important because it allowed scientists to concentrate light in a single beam. This provided scientists with many applications. Its properties also produce exciting effects. Until a laser beam collides with a large molecule, it travels in a straight line. The molecules in the air are much too small for a laser to reflect. Due to this, a laser beam is not visible in the air until it collides with a large enough particle. The actual physics behind lasers, as well as what constitutes a large enough particle, is much too difficult for further discussion here.


  • Related Demos

    The following demonstrations illustrate this physics topic:

    Sponsored by the Physics Department and the Center for Science, Mathematics, and Engineering Education -- University of Virginia