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Grade 12 AP physics: the Young's Double-slit experiment

October 25, 2016

Grade 12 AP physics: the Young's Double-slit experiment

Recently, two 12th Grade AP Physics classes conducted the Young's Double-slit experiment at the YiFu building. Through this experiment, the students were able to observe the wave nature of light, how light can have interference. The lab provided each group with a red laser source. As the laser is split by the double slits, bright and dark light patterns began to show up on the screen. Just as the students have learnt in class, the double-slit interference of light, mutually reinforcing and canceling each other out, creates light and dark stripes. Although most of students had sore eyes after staring at the plate for a period of time, they were not discouraged and were not willing to give up, knowing that hard work has to be put in for the experiment results. To avoid eye soreness, there was even a student who used an SLR camera to take a photo of the light patterns. During the experiment, the students tuned the disk and observed the diffraction gratings as light passed through the slits. They observed how light diverged into finer lines and understood how to measure the wavelength. Then, they moved the screen aside and turned on the computer. They slowly moved the photometric detector along a track to gather light intensity data. On the data chart, peaks and troughs were very clear. Although textbooks have vivid descriptions of the double slit experiment, they are presented in nearly all words, only having a few pictures. After the students completed their experiment, their understandings of the light interference theory have reached another level.

(Written by 12(7) Yuxuan Chen Picture by 12(8) Jiahua Lu Supervised by Ms. Sheng Li)