Science tells us that lightening is the reaction of positive and negative atoms coming into contact.
Thunder is the sound produced as the lightning disturbs the air.
Any sound is a disturbance in the air. My feelings are that thunder and lightning are God's reminders of His presence. As if just waking up each day was not enough of a reminder for us. He causes the clouds to rise over the earth. He sends the lightning with the rain and releases the wind from His storehouses.