There is audio interference. We talk about how to read the braid index of certain families of alternating knots from a minimal knot diagram. In addition we talk about a class of knots where the braid index equals the bridge index. These knots seem to have particular physical properties as demonstrated by several experiments. They undergo a periodic motion when sedimenting in a viscous fluid as knotted deformable closed chains, they also seem to achieve a circular minimum as elastic knots when their bending energy (curvature) is minimized.