What causes lightning?
http://www.planet-science.com/categories/over-11s/natural-world/2012/06/what-causes-lightning.aspx
can i tell you what i think how it causes lighting
When air rises and falls within a thunderstorm, positive and negative charges form in the cloud. The bottom of the thundercloud has a negative charge, and the top has a positive charge. A flash of lightning happens when a charge becomes so strong that the air can’t stop it from jumping from the cloud to the ground, which has a positive charge. Lightning can also form inside the cloud, moving between the positively and negatively charged areas. The average flash of lightning could turn on a 100-watt light bulb for more than three months. The air near a lightning strike is hotter than the surface of the Sun.
Lightning is a natural phenomenon that is caused by the buildup of electrical energy in the atmosphere. It typically occurs during thunderstorms, but can also be seen during volcanic eruptions or intense forest fires. The main cause of lightning is the separation of electric charges within a storm cloud. Here's a step-by-step explanation of how lightning is formed:
1. Water Droplets and Ice: Thunderstorms contain large numbers of water droplets and ice particles that are constantly moving within the cloud.
2. Collisions and Charging: As these water droplets and ice particles move around, they collide with each other, creating friction. This friction can cause electrons to be transferred between the particles, leading to a separation of electric charges. This separation can result in a positive charge building up at the top of the cloud and a negative charge accumulating at the bottom.
3. Electrical Field: The separation of charges creates an electrical field within the cloud. This field continues to intensify as more charges are separated.
4. Stepped Leader: At some point, the intense electric field from the cloud reaches out towards the ground in a series of steps known as "stepped leaders." These steps are not visible, but they serve as a path for the electrical charge to follow.
5. Streamer: When the stepped leader gets close to the ground, it induces a positive charge on the objects on the Earth's surface. This positive charge attracts a stream of electrons, called a "streamer," to reach up from the object towards the stepped leader.
6. Return Stroke: Once the streamer and the stepped leader meet, a completed electrical path is formed. This allows a massive flow of electrons, known as the "return stroke," to travel back up to the cloud. It is this return stroke that we see as a bright flash of lightning.
It's worth noting that there are variations of lightning, such as cloud-to-cloud or intra-cloud discharges, but the general process remains the same.