The lightning rod's lightning protection function is to divert lightning from the protected object towards itself and safely conduct it into the ground. Therefore, its lightning attraction and discharge capabilities are crucial. The lightning rod's lightning attraction properties have been experimentally and theoretically analyzed as follows:
A lightning rod standing on flat ground, with its simplified envelope being a parabola, which line represents the 50% average boundary of the rod's strike points hitting the ground under both positive and negative thunderclouds. The small circles denote experimental discharge statistics at various points in the air, indicating the tip positions of the leading discharge in simulated experiments. The black circle represents the strike point, the white circle the point of impact on the ground, with an equal balance of black and white indicating 50% strike points and impacts.

The principle of lightning rods
During thunderstorms, when charged cloud layers appear overhead in tall buildings, both the lightning rod and the top of the building are induced with a large amount of charge. Since the head is pointed, conductors accumulate more charge during static induction. As a result, the lightning rod accumulates most of the charge. The lightning rod also forms a capacitor with these charged cloud layers. Due to its sharpness, the opposing area of the capacitor plates is small, which means the capacitance is low, and thus it can hold a minimal amount of charge.
It also accumulates most of the charge, so when there is a lot of charge in the cloud layers, the air between the lightning rod and the cloud layer can easily be ionized, becoming a conductor. Thus, a path is formed between the charged cloud and the lightning rod, which is grounded. The lightning rod can then conduct the charge from the cloud to the ground, ensuring it doesn't pose a danger to high-rise buildings and guaranteeing their safety.

The function of a lightning rod
Installing a lightning rod is an effective method to prevent lightning strikes. A metal rod is erected at the house, with its lower end connected to a thick copper wire, which in turn is connected to a metal plate buried deeply in a moist underground area. The top of the metal rod must be a pointed tip or forked into several pointed tips. With this setup, when there are charged clouds in the sky, the lightning rod concentrates opposite charges due to electrostatic induction, causing a discharge that neutralizes the electricity within the clouds, thus preventing intense lightning. This is one aspect of how lightning rods can prevent lightning strikes.
But this effect is rather slow; if electricity accumulates quickly in the clouds, or if a cloud with a large amount of charge suddenly approaches, there may not be enough time to neutralize it in the aforementioned manner, resulting in a strong discharge and lightning may still occur. However, at this point, due to the lightning rod being taller than the surrounding objects and having concentrated charges of the opposite sign to those in the clouds, if lightning occurs between the clouds and ground objects, the discharge current primarily flows through the lightning rod into the earth, thus preventing it from striking the house or nearby individuals; it will only strike the lightning rod.
Thus, the lightning rod's discharge function reduces the likelihood of lightning strikes between the ground and clouds; when it's unavoidable, it bears the brunt of the lightning strike, ensuring safety for the house and people.
Due to the construction and function of lightning rods, we must pay special attention to maintaining their good conductivity. If there's a poor connection or a break, the section above the break becomes an isolated conductive system. When there's an electric charge in the clouds, the upper part of this section induces a charge of the opposite sign to that in the clouds, while the lower part induces a charge of the same sign. If the upper part and the charge in the clouds discharge, the powerful discharge current can only be released through the building, releasing a large amount of heat and causing lightning strike. This not only fails to prevent lightning but actually invites lightning灾害.

Lightning Rod Basics
Lightning rods do not attract lightning.
2. Lightning rods do not guarantee the prevention of lightning strikes.
3. Lightning rods do not release an electric field in the clouds.
4. Lightning rods are directly grounded, and when installed correctly, they help protect the structures of buildings and other objects. Essentially, lightning rods increase the probability of contact with lightning, giving them more opportunities to channel the massive current to the ground.
5. There are many different styles of lightning rods, including hollow, solid, pointed, round, and flat, some even resembling a brush. All lightning rods are made of conductive materials such as copper and aluminum. Among them, stainless steel and galvanized steel are commonly used as lightning protection materials.