COLOR AND SPECTRA

11/13/2012

 1.THE SPECTRUM OF WHITE LIGHT
FIRST WE SET UP THE EQUIPMENT. USE A STRAIGHT FILAMENT LIGHT BULB AS A WHITE LIGHT SOURCE. HOLD A DIFFRACTION GRATING 2 TO 5 CM IN FRONT OF ONE EYE.

 WE CAN LOOK FOR A RAINBOW OF COLORS ON EITHER SIDE OF THE BULB.
THE FOLLOWING PICTURE IS SHOWING THE SPECTRUM OF WHITE LIGHT.

THEN WE MEASURE THE DISTANCE OF EVERY COLORS AND COLLECT THE DATA.

 THEN WE USE THE EQUATION TO SOLVE FOR WAVELENGTH OF RED, BLUE, GREEN LIGHT. NOTICE THAT WE NEED TO USE LINEAR TRANSFORMATION TO CALCULATE THE FINAL WAVE LENGTH OF LIGHT.THE FOLLOWING PICTURE IS THE ANSWER WHAT WE GET.

 2. SPECTRA OF A HYDROGEN GAS
REPLACE THE SOURCE WITH A HYDROGEN GAS TUBE. BE CAREFUL, THERE IS ABOUT 5000 VOLTS ACROSS THE EXPOSED TERMINALS OF THE POWER SUPPLY.

 THE FOLLOWING PICTURES ARE THE SPECTRA WE SEE IN A HYDROGEN GAS.AND REPEAT MEASURING THE DISTANCE AND COLLECT DATA.

 USE THE SAME EQUATION ABOVE TO SOLVE FOR THE BRIGHTER LIGHT. ANYWAY, WE ONLY SEE THREE LINES IN SPECTRA.THEN WE ALSO CALCULATE THE THEORETICAL DATA BY USING THE DEFINITION EQUATION AND WE ALSO CALCULATE THE ERRORS BETWEEN THOSE DATA. SINCE WE GOT A BIG ERRORS IN THE PREVIOUS PART,IN THE PART WE GET A BIG ERRORS TOO.

 3.CHALLENGE
WE REPLACE AN UNKNOWN TUBE AND REPEAT THE STEPS ABOVE.

 HERE ARE WHAT WE SEE IN SPECTRA.

HERE'S THE THING, BECAUSE WE DON'T KNOW WHAT GAS IT IS, WE COMPARE TO THE SOURCE ONLINE WHICH IS A SPECTRAL LINES CHART. 

 AFTER CALCULATING THE WAVELENGTH AND COMPARE TO THE SPECTRAL LINES CHART, WE DETERMINE THE GAS IS HELIUM.

FINALLY, OUR PROFESSOR TELLS US OUR GUESS IS CORRECT!!!!!!!!!!!