Presentation slides

Detailed research report

Diffraction is the bending of light around barriers or through narrow openings. Diffraction helps understand the atomic structure of different materials and measure the thickness of very small objects that can’t be measured with a ruler. Light energy travels in oscillating waves. The length of each oscillating wave, called wavelength, varies for different types of light. The objective of this experiment is to understand how the wavelength of light affects the amount of bending due to diffraction. The hypothesis is that the angle of diffraction increases when the wavelength of light increases.

Two light sources, a red laser with 635nm wavelength and a green laser with 532nm wavelength, a diffraction grating with 0.1mm slit width, and a screen to capture diffraction patterns are used for this experiment. Light is passed through the slit, and the angle of diffraction is calculated from the width of the central light blob recorded on a screen placed at a distance from the slit. The widths are recorded with both lasers for 3 different distances from the slit to the screen with 3 trials.

The hypothesis is proven by the results. The mean angles of diffraction are 0.36 degrees for the 635nm wavelength source and 0.29 degrees for the 532nm wavelength source. This shows that the angle of diffraction increases as wavelength increases.

Further research with different wavelength sources can help determine the pattern of relationship between diffraction and wavelength. The effect of different slit widths on the angle of diffraction can also be explored.