Before students can understand the diffraction patterns associated with a helical object, they will need a basic grounding in single-slit and multiple-source diffraction. This mobile-friendly simulation lets users explore wave patterns generated by a water wave, sound wave, and a light generator. You can choose a simple wave, interference of two waves, single and double-slit diffraction, and diffraction patterns caused by shining colored lights through different geometric shapes. PhET has embedded robust tools in this new HTML5 version, including auto-generated graphs of E-Field vs. Position, Pressure vs. Position, slit width and separation, frequency, and amplitude.

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Here you'll find an exemplary collection on DNA and RNA structure including interactives, animated videos, virtual labs, and turn-key lessons for the high school classroom. Topics include DNA sequencing/coding, transcription and translation, CRISPR technology, RNA folding, role of genes in disease, the biology of COVID-19, human chromosome structure, and more. All resources are free and device-compatible. Highly recommended by the editors.

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How did Rosalind Franklin discover the helical structure of DNA? The X-Ray Diffraction JavaScript Model computes diffraction patterns from first principles for simple apertures including a sinusoidal wave corresponding to a 2D projection of a helix. The model is ready to run on tablets and mobile devices, requiring only JavaScript support. Students can select 2D X-ray diffraction or a companion model with 3D configurations.

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This tech lab was developed by Paul Hewitt and Dean Baird, the authors of Conceptual Physics, specifically to accompany the PhET simulation "Wave Interference". It provides explicit instructions for using the sim to explore interference pattern geometry. Note: Access to this resource is available to registered users of PHET. Registration is free.

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