This is a very nicely designed site, but I have to grumble a little: bivectors aren't a concept unique to geometric algebra! They've been used elsewhere in physics for ages: well before geometric algebra in its current form was developed. (I first encountered them in the Petrov classification of spacetime structures.) So it's a bit awkward to see "bivector.net" as a label for geometric algebra resources. (And they're not alone: the Wikipedia article on bivectors reads as if geometric algebra is the only context where bivectors are meaningful, too.)
In fact, I've recently written a paper[] about teaching rotational physics using the language of bivectors instead of cross products: deep down, bivectors are the right* language for rotations. (The cross product/pseudovector form is an accident of three dimensions, with awkward transformation properties under reflections or when extended to relativity.) There's absolutely no geometric algebra necessary, though more than one proponent of GA has told me they think this approach could be a nice first step toward teaching that formalism.
[*] I haven't had time to upload the accepted version of the paper yet (with improvements after peer review at AJP), but the original version is here: https://arxiv.org/abs/2207.03560
Thank you for sharing, I enjoyed reading the paper and gained some insights. To me, bivector makes rotation vastly more intuitive (the gyroscope precession example is case in point).
I've heard that geometric algebra is really useful, but I'd be curious to hear of concrete examples. For common computer graphics it feels like the standard vector + vector math (dot product, cross product, etc) and matricies are more or less sufficient. What does geometric algebra help you do?
I'm not an expert, but my understanding is: matrix rotations in 3d can lead to gimbal lock. That's why most 3d engines use quaternions instead. Geometric algebra offers a simpler alternative to quaternions.
In fact, I've recently written a paper[] about teaching rotational physics using the language of bivectors instead of cross products: deep down, bivectors are the right* language for rotations. (The cross product/pseudovector form is an accident of three dimensions, with awkward transformation properties under reflections or when extended to relativity.) There's absolutely no geometric algebra necessary, though more than one proponent of GA has told me they think this approach could be a nice first step toward teaching that formalism.
[*] I haven't had time to upload the accepted version of the paper yet (with improvements after peer review at AJP), but the original version is here: https://arxiv.org/abs/2207.03560