The socks also contain a man-made fibre (probably) and the friction between the sock material when you move it leads to an accumulation of static charge on the socks. When this charge dissipates (discharges) through the sock material it excites molecules in the sock material; this manifests as flashes of light.
It's the same phenomenon
The socks also contain a man-made fibre (probably) and the friction between the sock material when you move it leads to an accumulation of static charge on the socks. When this charge dissipates (discharges) through the sock material it excites molecules in the sock material; this manifests as flashes of light.