The Young's Experiment Interactive is an adjustable-size file that displays nicely on smart phones, on tablets such as the iPad, on Chromebooks, and on laptops and desktops. The size of the Interactive can be scaled to fit the device that it is displayed on. The compatibility with smart phones, iPads, other tablets, and Chromebooks make it a perfect tool for use in a 1:1 classroom. 


Teaching Ideas and Suggestions:

This Interactive simulates a modern day version of Thomas Young's famous double slit experiment. This classic experiment involves passing sunlight through two closely-spaced slits in a card and projecting the resulting interference pattern onto a distant wall. Three different length measurements allowed Thomas Young to calculate the wavelength of the light. In this modern-day, simulated version, lasers are used as the source of monochromatic light. A front-view of the interference pattern that is projected onto the distance screen can be used to determine the spacing between adjacent bright bands on the screen. It is recommended that learners make this measurement from the most visible band on the left side of the pattern to the most visible band on the right side of the pattern. This provides a value of y in the wavelength = y•d/(m•L). Values of d and L are reported on the Interactive. These can be easily changed by tapping on the slits or by dragging the screen forward or backward. Learners must compute the wavelength of all three lasers and select the answers using the sliders near the bottom of the Interactive. Once the three values have been determined, the answers can be checked. Feedback is immediate. If there is one or more incorrect answers, learners must carefully analyze their measurements and calculations and try again. Three attempts are provided.

The nature of the activity and the feedback that is provided makes this Interactive an excellent summative assessment of student understanding of Young's Experiment. Instructors can simply ask students to show them their screen once they have successfully finished the activities. Those who are not successful after three tries will have to reload the page and try again wwith a fresh set of three tries.

The Physics Classroom has provided a ready-to-use classroom exercise for use with this Interactive. The exercise guides students through both the conceptual and the mathematical analysis of Young's experiment. View Exercise.


Related Resources

There are numerous resources at The Physics Classroom website that serve as very complementary supports for the Young's Experiment Interactive. These include:
  • Reading:
    Lesson  3 of the Light and Color Chapter of the Tutorial are perfect accompaniments to this Interactive. The following pages will be particularly useful in the early stages of the learning cycle on light and color:

    Anatomy of aTwo-Point Source Interference Pattern

    The Path Difference

    Young's Equation

    Young's Experiment

    Other Applications of Two-Point Source Interference

  • Curriculum/Practice: There are several Concept Development worksheets at the Curriculum Corner on the topic of light and color. None of them specifically address the topic of two-point source interference. However, you will find serveral useful think sheets that pertain to electromagnetic waves and the wave behavior of light.

    Visit the Curriculum Corner.

  • Labwork: 
    Simulations should always support (never supplant) hands-on learning. The Laboratory section of The Physics Classroom website includes several hands-on ideas that complement this Interactive. Three notable lab ideas include ...

    Ripple Tank Lab
    Two-Point Source Analysis Lab
    Young's Experiment Lab

    Visit The Laboratory.

Additional resources and ideas for incorporating the Young's Experiment Interactive into an instructional unit on Light and Color can be found at the Teacher Toolkits section of The Physics Classroom website.  Visit Teacher Toolkits.


The Physics Classroom would like to extend a special thanks to Nerd Island Studios for the creation of this HTML5 Interactive. Visit to see more great stuff by Nerd Island Studios.

Visit: Interactive | Exercise


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