elysiatoolsDiscover 6 interactive science visualizations — from the Law of Cosines and Fourier Series to the Doppler Effect and Mandelbrot Set — that make math and physics intuitive and fun.
Ever tried to explain the Doppler effect to someone and watched their eyes glaze over? Or tried to describe why the Mandelbrot set is beautiful to someone who has never seen it? Words and equations only get you so far. Sometimes, you just need to let people play with the concepts.
ElysiaTools is a free, open-source collection of interactive science and math visualizations. In this article, I want to walk you through six visualizations that I think are absolutely essential — the kind of interactive tools you wish you had when you were learning this stuff in school.
The Pythagorean theorem is great for right triangles. But what happens when your triangle is obtuse, or when you only know two sides and the angle between them?
The Law of Cosines handles exactly this: c² = a² + b² - 2ab·cos(C). It's a generalization of Pythagoras that works for any triangle.
The interactive Law of Cosines visualization (https://elysiatools.com/en/visualizations/law-of-cosines) lets you:
What I love about this one is the verification panel — it shows you both sides of the equation calculated numerically, so you can see them converge to equality as you drag the triangle around. It makes the abstract relationship suddenly feel concrete.
This is, in my opinion, one of the most beautiful ideas in all of mathematics.
Any periodic function can be represented as a sum of sine waves. Square wave, sawtooth wave, even a hand-drawn squiggle — all of them can be broken down into a collection of rotating circles (called epicycles) whose radii and speeds correspond to the amplitude and frequency of each sine component.
The Fourier Series visualization (https://elysiatools.com/en/visualizations/fourier-series) lets you:
The epicycle animation is mesmerizing to watch. As you increase N, the jagged, imperfect reconstruction gradually smooths out into your original drawing. It's a visceral, hands-on demonstration of a concept that usually takes a full semester of university math to really internalize.
Applications span: Audio compression (MP3), image compression (JPEG), signal processing, 5G technology, quantum mechanics, and vibration analysis.
You've experienced this a thousand times. An ambulance drives toward you with its siren blaring — high pitch. It passes you and drives away — suddenly the pitch drops. That's the Doppler effect: the frequency of a wave changes depending on the relative motion between the source and the observer.
The Doppler Effect visualization (https://elysiatools.com/en/visualizations/doppler-effect) gives you:
Real-world applications: Radar and sonar speed measurement, medical ultrasound imaging (measuring blood flow velocity), astronomy (measuring stellar velocities via redshift/blueshift), weather radar, and even laser cooling in quantum physics experiments.
A double pendulum is just two pendulums attached end to end. Sounds simple. But throw it into motion and it becomes one of the most chaotic, beautiful, and educational systems in all of physics.
The Double Pendulum visualization (https://elysiatools.com/en/visualizations/double-pendulum) offers:
The butterfly effect demo is the real highlight here. You can literally watch a difference of 0.001 radians grow into completely different trajectories within seconds. It's the most intuitive demonstration of sensitive dependence on initial conditions you'll ever find.
Why it matters: The double pendulum is a canonical example of deterministic chaos — a system that follows exact physical laws but is nonetheless unpredictable over long time horizons. It's the same reason weather forecasts are unreliable beyond about 10 days.
The Mandelbrot set is defined by one of the simplest possible formulas in mathematics: z_{n+1} = z_n² + c. You iterate it starting from z₀ = 0 for each point c on the complex plane. If the result stays bounded (never escapes beyond magnitude 2), the point is in the set.
That's it. And yet — the boundary of this set is infinitely complex.
The Mandelbrot Set explorer (https://elysiatools.com/en/visualizations/mandelbrot-set) gives you:
What makes the Mandelbrot set a fractal is its self-similarity: no matter how deep you zoom, you always find smaller copies of the overall shape nested within the boundary.
Applications: Generative art, computer graphics, data compression research, and as a teaching tool for complex number arithmetic and iteration.
The logistic map models population growth with a brutally simple formula: x_{n+1} = r·x_n·(1 - x_n). Given a growth rate parameter r and an initial population fraction x₀ (between 0 and 1), you just iterate.
Here's what happens as you increase r:
The Logistic Map visualization (https://elysiatools.com/en/visualizations/logistic-map) gives you three complementary views:
Why the logistic map matters: It helped change how scientists thought about predictability in nonlinear systems. The ratio of successive bifurcation intervals converges to the Feigenbaum constant δ ≈ 4.669 — a universal constant that appears in many different chaotic systems, independent of the specific equation.
These six visualizations are just the beginning. ElysiaTools currently hosts dozens of interactive tools across math, physics, chemistry, economics, signal processing, and more — all completely free, all open-source.
Whether you're a student trying to build intuition, a teacher looking for interactive demos, or just someone who finds beauty in scientific concepts, there's something here for you.
Which visualization is your favorite? Have one I didn't cover that you think deserves more attention? Drop it in the comments!