How does lightning strike?
Scientists have learned that #lightning begins with negative charges (-) within a thunderstorm. When those (-) charges become great enough, the charge begins to make a path, a path of least resistance to positively charged earth. Since lightning is an electrical phenomenon, the charges or current seeks out conductors of electricity. This could be anything from trees, grass blades, a rock, or even a wave in the ocean.
A step-leader, which is a “feeler” for the (-) negative charge starts down the path seeking wherever it can to find a (+) positive charge. Nearing the ground, the step-leader begins to have a reaction to the (+) positive charges on the surface. The result is a “streamer” reaching up to meet the step-leader to complete the giant electrical circuit.
When the (+) positive streamer and (-) negative step-leader meet, a “channel” is made. This is when the visible lightning that we see happens as the return stroke violently explodes from the surface into the clouds.
What is thunder then?
Thunder is nothing more than extremely hot air expanding so fast that it creates a shock wave. Basically, the bolt of lightning is so hot that the air the bolt travels through explodes away from the bolt faster than the speed of sound. Our ears perceive this noise as thunder and since a lightning bolt travels from the tops of the storms down to the ground, there are “shock waves” from different altitudes. The resulting effect is the rumble you hear that accompanies #thunder.