General Relativity part 1: What is curvature?

In six Level 1 videos we visualize General Relativity with a substratum (“fabric”) that uses the same math as GR, the math of curved surfaces.

Here in part 1 of 6: What is curvature? In 2-d, we show curvature as either a deformation of pixels within the 2-d surface, or as a buckling out into a 3rd, embedding dimension. We morph between a sphere and Feynman’s hot plate.