18) Lighting strikes all around the world at a constant rate yet we see that buildings are not constantly being set on fire. Draw a diagram and explain how tall buildings can handle year-round lighting strikes (3)

Tall buildings are designed to safely conduct the immense electrical current from a lightning strike to the ground, preventing fire and damage. This is achieved primarily through a system called a **lightning protection system (LPS)**, often referred to as a "lightning rod" system, although it's more complex than a single rod. Here's how it works:<br /><br />**Diagram:**<br /><br />```<br /> ☁️ Cloud (+)<br /> ⚡️<br /> ⮛ Air Terminals (Metal Rods)<br /> ⮛ Down Conductors (Metal Cables)<br /> ⮛ Grounding Electrode (Metal Grid/Rods)<br /> ⮛<br /> 🜨 Ground (-)<br />```<br /><br />**Explanation:**<br /><br />1. **Air Terminals (Lightning Rods):** These are strategically placed metal rods or conductors, typically made of copper or aluminum, that project above the roof of the building. They are the highest points and are designed to intercept the lightning strike.<br /><br />2. **Down Conductors:** These are thick, insulated copper or aluminum cables that run vertically along the exterior walls of the building, connecting the air terminals to the grounding electrode. Multiple down conductors provide redundant paths for the current.<br /><br />3. **Grounding Electrode:** This is a network of metal rods or a grid buried in the ground near the building's foundation. It provides a low-resistance path for the lightning current to dissipate harmlessly into the earth.<br /><br />**How it prevents fires:**<br /><br />* **Controlled Path:** The LPS provides a low-resistance path for the lightning's electrical current to follow, bypassing the building's flammable materials. Instead of arcing through the structure and igniting a fire, the current flows safely through the metal conductors to the ground.<br />* **Rapid Dissipation:** The grounding electrode ensures the current is quickly dispersed into the earth, minimizing the duration and intensity of the electrical surge within the building.<br />* **Surge Protection:** While the LPS handles the main current, additional surge protection devices are often installed within the building's electrical system to protect sensitive electronic equipment from any residual voltage spikes.<br /><br /><br />This system, combined with building codes and regulations regarding fire-resistant materials, ensures that even with frequent lightning strikes, the risk of fire is significantly reduced.<br />