Triangle webs: energy before impact
Follow a triangle weaver's loading and release sequence, then test how preload changes the lab's starting extension.
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Original WebTug explanation with animated teaching diagrams and credited still photographs. On-screen text carries the lesson; there is no audio narration.
Diagrams simplify the science. Animation timing and diagram dimensions are illustrative, not measurements of live spiders.
Compare triangle preload →Read the full transcript
- Meet the triangle weaver
Hyptiotes cavatus builds a triangular web. This still photograph introduces the spider; the following diagrams explain its moving trap.
- Load the silk before the strike
The spider repeatedly tightens a separate anchor line with its legs. Muscular work builds elastic energy in the stretched web.
- Release the held line
When prey contacts the web, the spider releases its grip. Stored energy accelerates both spider and web toward the insect.
- Motion brings more silk into contact
The spider's sudden halt makes the web jerk and wrap additional capture threads around prey. Loading, release, and stopping work together.
- A spring is a simplification
Our lab uses one damped spring. A living triangle web has multiple lines and staged releases; its preload is not calibrated here.
- What changes with more preload?
Keep stiffness and energy loss fixed. Increase preload energy, then compare the loaded extension and motion after release.
Scientific sources and media credits
Hyptiotes cavatus — Triangle-web Spider - Hyptiotes cavatus, Julie Metz Wetlands, Woodbridge, Virginia.jpg by Judy Gallagher, CC BY 2.0. Photograph fitted within the video without changing its composition; labels and animated diagrams added around it.
Script, diagrams, animation, and editing: WebTug, September 27, 2026. This video adaptation is available under CC BY-SA 4.0; individual photographs retain their credited licenses.
What the game helps you notice
Triangle weavers preload a web through an anchor line, then release stored energy. Here, charge sets extension; spring energy grows with extension squared, and launch speed follows the stored energy.
Does twice the stretch mean twice the energy?
Not in the ideal spring model: E = ½kx², so doubling extension stores four times the energy at the same stiffness.
The upward target course and single launch are arcade abstractions. Real Hyptiotes moves with its web toward intercepted prey and can release in repeated stages.
Try this experiment: What changes when the web starts with more energy?
Keep web stiffness and energy loss unchanged. Compare low and high preload energy, starting each replay at the same phase.
Open this experiment and compare A / B →Meet Hyptiotes cavatus and explore its research, then use the return link to play again. The challenge scores are game feedback, not measurements of your scientific understanding.
Primary research: Han et al., Proceedings of the National Academy of Sciences (2019)