Salt-Powered Electricity in Your Cells

You are literally a walking battery powered by salt. Your cells hold an electrical charge

called membrane potential, sitting at negative seventy millivolts because potassium

constantly leaks out while sodium waits outside. But the second you need to move or

think, those floodgates open. Sodium rushes in, flipping the switch

from negative to positive in milliseconds. This explosion of electricity is called an action potential.

It is the exact signal that tells your muscles to contract and your nerves to fire,

proving you are just as much physics as you are biology.