thermodynamics.gif (19136 bytes)

FOCUSING LIGHT TO BURN WOOD
(No longer done.)








EQUIPMENT
    redball.gif (326 bytes) 2, Large Parabolic Mirrors
    redball.gif (326 bytes) Carbon Arc Lamp
    redball.gif (326 bytes) Resistor Box
    redball.gif (326 bytes) Switch
    redball.gif (326 bytes) 130 VDC Power Supply
    redball.gif (326 bytes) Treated Wood Splints



NARRATIVE
            Light energy can be focused and converted into heat energy. Place the two large parabolic mirrors on the ends of the two moveable lecture tables. Place the carbon arc lamp at the focal point of one of the mirrors (about 42 cm). Connect the lamp through a switch and the large load resistor with ALL switches closed to 130 VDC from the large generator. Bring the lower carbon rod up to the horizontal rod until an arc is struck. Move the rod back down until the light is at maximum intensity. Check to see that the beam from this mirror is parallel (that is, the beam just fills the other mirror) and that the lamp is at the focal point. Place a piece of thin wood which has been treated to burn easily at the focus of the second mirror. Make small adjustments to the lamp and wood splint so that the smallest sized spot is obtained.