The comparison between pliny's and today's thinking of thunder and lightning.
...d these bolts of lightning come out usually when there is a storm. He then describes Thunder and its connection with Lightning in another passage. He says that when a bolt of lightning is sent it makes a crackling sound, but that is not the thunder. The thunder is a noise that the lightning bolt makes when it comes crashing down into the cloud. If the bolt breaks through the cloud then you see a bolt hit the earth, but he said that if the bolt cannot break free from the cloud, it stays trapped inside and that is when you see the sky light up without seeing the bolt. And when it gets trapped inside it bounces around inside the cloud making more noise. Lightning is the result of the separation of charges within a cloud. The separation of charges within a cloud, is caused by cosmic particles bombarding with particles in the atmosphere. This causes electrons from the particles to be knocked free, and turn into negative and positive charges. Since these charges repel each other, they separate to opposite sides of the cloud. What happens at this point is that the negative charges in the cloud start extending towards the ground, and at the same time positive charges extend from the ground to the cloud. The negative charges do this because the air becomes ionized surrounding it, which allows the charge to continue extending towards the ground. Now at the ground level, just about anything sends electrically positive charges to meet the negative ones descending. Now the reason we hear thunder is because a strike of lightning is incredibly hot. A typical bolt of lightning can immediately heat the air to between 15,000 to 60,000 degrees Fahrenheit. A lightning strike can heat the air in a fraction of a second. When air is heated ...