A laser beam is made visible by the mist from a fog machine
Laser beams are coherent light that is nearly monochromatic. They do spread out with distance (contrary to popular perception) but the spreading angle is very small.
NCEA & Science Curriculum
JNR SCI, SCI 1.3, SCI 2.9, PHYS 1.4, PHYS 2.3
Access to a laser beam and a fog machine.
Lasers have been in the news quite a lot lately. One can purchase really quite dangerous lasers on the internet. Be sure your laser is low power and safe, and be very careful with it.
Individual teachers are responsible for safety in their own classes. Even familiar demonstrations should be practised and safety-checked by individual teachers before they are used in a classroom.
LASER is an acronym that stands for Light Amplification by Stimulated Emission of Radiation. Stimulated emission, in which a suitable photon interacts with an atom in an excited state, results in the production of a pair of essentially identical photons. To make a laser beam, you have to get the majority of atoms that produce the laser beam in the same excited state. This is called a population inversion and it is not easy to achieve.
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