Young's Experiment Activity Sheet (Adapted from www.physicsclassroom.com) Purpose: The purpose of this activity is to perform Young's experiment in a simulated environment in order to determine the wavelength of light. Background: In this activity, you will analyze a two-point source light interference pattern that is projected onto a screen. The interface is divided into three important sections. The top section represents the experimental set-up as it would be seen in the lab. The set-up consists of a laser beam of unknown wavelength, a double slit, a screen upon which the interference pattern is projected. Tap the Tap Me laser to change the wavelength; tap the double Drag Me slit to change the slit separation distance; drag the screen to move it towards and away from the double slit. The middle section represents the front view of the screen. This view allows you to see the actual interference pattern consisting of bright and dark bands. These bands are the result of the wave interference of the waves for the waves diffracting through the two slits. The cm-ruler can be used to measure the distance between bright bands on the interference pattern. Adjust the slit size and screen location so that you obtain nodal lines that are easy to read on This distance goes from 8 cm to 12 om and represents the ruler. Measure the overall distance for the central 5 bands and SAN values. 50, divide by 5 to obtain Ax. SAM = 4.0 cm Ax = 4.0 om/5 = 0.8cm 20 cm The bottom section allows you to check your answers for the wavelength of light for the three different lasers. Once you have measured values of Ax, d and D, you can calculate the wavelength of light in nanometers and select the answer using the slider. Once you have determined the wavelength of all three laser beams, a Check Answer button is available. If you want, you can click the button to check your answers. (Pro-tip from the Half Blood Prince - slight imprecisions in your measurements can cause answers that are close to the correct value, but outside what the computer simulation will accept as correct. You can drive yourself crazy trying to get all 3 answers correct..don't worry about trying to get answers as indicated "correct" by the software - it is more unforgiving than a Dementor)Go to the link provided in D2L and begin to familiarize yourself with the controls for the experiment. Notice that you can change the size of the simulation window to make it easier to read. Once you are ready, record your observations: Observations: Ensure all distances are recorded in meters. Use scientific notation Laser Distance for Distance for Slit Separation d Screen Distance 5Ax (m) Ax (m) (m) D (m) Red Green Blue Calculations: Show your work (clearly) for the calculation of the 3 wavelengths. Pay attention to units. Analysis Questions 1. Drag the screen closer and further from the card with the two slits. This changes the value of D. Observe the changes in the pattern that is projected onto the screen. Complete the following: a. As the screen is moved further from the slits, the distance between bright bands (increases, decreases, remains the same). . As the screen is moved closer to the slits, the distance between bright bands (increases, decreases, remains the same]. c. The band separation distance (Ax) and the slit-to-screen distance (D) are (directly, inversely) related. 2. Change the color of the light by tapping on the laser. Each color is characterized by a unique wavelength; red is longest and blue is shortest. Observe the changes in the pattern that is projected onto the screen. Complete the following: a. As the wavelength is increased, the distance between bright bands (increases, decreases, remains the same). b. As the wavelength is decreased, the distance between bright bands (increases, decreases, remains the same]. C. The band separation distance (Ax) and the wavelength (A) are (directly, inversely) related. 3. Use the pull-down menu for Slit Separation Distance to investigate the effect of changing the distance between slits. Observe the changes in the pattern which is projected onto the screen. Complete the following sentences: a. As the slit separation distance is increased, the distance between bright bands (increases, decreases, remains the same) b. As the slit separation distance is decreased, the distance between bright bands (increases, decreases, remains the same). c. The band separation distance (Ax) and the slit separation distance (d) are (directly, inversely) related. What to Submit: Purpose, Observations, Calculations, Answers to the Analysis Questions (full sentences)