How does lightning arise and what are the consequences?
Lightning is a natural phenomenon in which strong forces play a role. There are several theories about the origin of this. The best-known theory is Wilson’s induction theory. According to this theory, positive and negative charged particles are increasingly split from each other. This happens because of the strong wind that is in the storm. Ultimately, the electric fields have become so strong that the particles flow back together at a rapid pace. Lightning often has major consequences for the environment because of its power.
The origin of lightning & various theories
Lightning usually occurs when a severe storm is present. There are mainly three different lightning types, namely intra-cloud (also known as intra-cloud), cloud-cloud (or cloud-to-cloud) and cloud-ground (cloud-to-ground). These names indicate the location of the lightning. For example, intrawolk is lightning within one cloud while cloud-cloud is lightning moving between two clouds. Before lightning can occur, the storm must meet certain requirements. The different theories describe these unique conditions. However, scientists agree that lightning consists of multiple discharges because one electrical discharge is not enough to bridge the distances.
The different theories
According to one of the theories, for example, ice must be present in the clouds before lightning can occur (the thermoelectric effect). This theory was coined by Mason and Latham. The other theories are Findeisen’s theory and Simpson’s waterfall theory (fragmentation theory). The best known and most likely theory is Wilson’s theory of induction. The current science of lightning and atmospheric research is based on this. According to this theory, there must be a split of positive and negative charged particles.
The Thermoelectric Effect (Mason and Latham Theory)
According to Mason and Latham’s theory, lightning is created when pressure differences arise. Because of these pressure differences (‘convection’) different charges would move in the air. However, like most theories of lightning origin, this theory is a setup that is less popular and likely than Wilson’s theory.
According to Simpson, a charged distribution of water droplets is created within a storm. According to this theory, the water droplets are arranged in a polarizing manner until the electric field is strong enough to create lightning. According to this theory, the water droplets move in a certain way within the clouds according to the wind, droplet size and gravity.
Findeisen’s theory is based on the idea that hail colliding in clouds can generate an electrical charge. The origin of this theory comes from experiments that have been done with ice surfaces. It turns out that growing ice surfaces can become positively charged and melting ice surfaces can become negatively charged.
Before lightning occurs, all kinds of electric fields are built up. These electric fields arise when the fast winds increasingly split the positive and negative charged particles. Larger water droplets that are in the storm become more negatively charged than positive and bring these negative charges down. These small charged particles that are moved are called ‘ions’ and attract each other. The process of separating the particles is also known as polarization. Only when the electric fields are strong enough, a bridge from the clouds to the earth is possible.
The opposite direction
The negatively charged particles start to flow towards the earth at a high speed. This is also called the stepped leader (in English this is called the so-called ‘stepped leader’). Positively charged particles then flow from the highest points of the Earth’s surface towards the clouds. This is a reaction to the negative particles that descend from the cloud cover at a rapid pace and is also called the main stroke or ‘return stroke’. The positive and negative charges usually meet at a height of about 30 to 100 meters. Then the negative charge flows to the ground. The stronger positive charge flows towards the cloud cover. However, this is when a bright light can be seen. So the effect of lightning actually goes in the opposite direction; from the earth towards the cloud cover.
The difference between positive and negative lightning bolts
Most lightning bolts are negative (about 95 percent). These are lightnings that travel from the clouds towards the earth from a negative charge. The earth is positively charged here. When one speaks of a positive lightning bolt, the lightning comes from the top of the cloud cover which is positively charged. This rare phenomenon can cause more damage and is usually the reason that a forest fire starts naturally.
The effects of lightning
Danger to persons
The chance that you will be hit by lightning is minimal, but lightning is very deadly. Due to the high tension, your body is heated enormously within a short time. Because of this there is a considerable risk of heart failure and burns.
Avoiding the highest point
During a thunderstorm it is recommended to look for protection near buildings or vegetation that are not high. It is important to avoid tall objects. In addition, it is important not to be the highest point yourself.
Objects with a metal frame can serve as a Faraday cage. A car or boat (with metal parts) that can be locked can provide effective protection.
Dry areas can catch fire from lightning. As a result, forests and dry plains can disappear at a rapid pace. In the longer term, however, this is good for nature because it makes the soil fertile again. However, this usually takes one or more years.