Why Do Spark Plugs Break Windows?

Dustin Hawley | Jan 05, 2023

Car windows are made to be reliable and withstand damage during an accident. However, if you ever get stuck inside the car and your doors are jammed, you can use a spark plug to break the windows in an emergency. You would ask why a spark plug works better at breaking a window than a hammer or any other object.

Why Do Spark Plugs Break Windows

Spark plugs instantly break windows when thrown at the glass with sufficient force because they are generally made of aluminum oxide ceramic or porcelain, which concentrates a tremendous amount of energy at a single focal point on the glass. 

What Are Spark Plugs?

Most things might fail at efficiently breaking window glass, but not spark plugs! As the name suggests, Spark plugs are small components that create a spark to ignite the gasoline in the internal combustion engine. The spark plug is connected to the ignition system and a central electrode through a threaded metal shell that protrudes into the cylinder. The spark plug must be made of a hard material that can withstand high temperatures and pressure to work efficiently. Incidentally, this also makes them a perfect tool for shattering windows.

Types Of Spark Plugs

There are three different kinds of spark plugs. Let’s take a closer look at each one of them. 

Copper Spark Plug

Copper spark plugs are the market’s most common spark plug—a spark plug with a nickel alloy shell and a copper core. Copper is ideal for spark plugs due to its electrical and thermal conductivity. The only drawback is that copper is a soft metal, making the spark plugs wear out much faster. 

Platinum Spark Plug

Platinum spark plugs have a platinum-coated electrode. Platinum is more rigid than copper, which makes it last longer. It has two varieties:

  • Single platinum spark plug - It has a platinum-coated electrode on the center electrode. The side electrode is made of copper. This ensures good electrical conductivity while still providing the benefits of platinum.
  • Double platinum spark plug - It has a platinum-coated electrode on both the center and side electrodes, which helps improve the spark plug’s lifespan.

Iridium Spark Plug

The iridium spark plugs are ideal for high-performance engines. It features a thin wire center electrode that fires more sparks. The electrode is coated with iridium in an Iridium spark plug which is harder than platinum making it sturdier and long-lasting.

Factors That Make A Spark Plug Shatter Windows Easily

Let’s take a look at the physics behind why spark plugs are so effective at shattering your car’s glass windows:

The Ceramic Insulator

Spark plugs are made of aluminum oxide ceramic or porcelain that focuses a lot of energy at a singular point when thrown at the glass, causing the glass to shatter. 

The Weight

The ceramic material is very dense, making it heavier than most other objects of the same size. This means it also puts more pressure per square inch on the glass when you’re trying to break it.

Steps To Use A Spark Plug To Break Your Car Window

If you ever find someone stuck in a car and need to break the windows or the windshield to get them out, here is what to do:

  • Find the spark plug in the car. The spark plugs are located at the top of the cylinder head. The piston moves down the cylinder, where it takes in a combination of air and fuel. Next, the piston travels back up to the spark plug, compressing the mixture. If there is a spare spark plug, that will work best. Don’t use a new spark plug. 
  • Break the plug and remove the AC/DC converter. After tapping the spark plugs open, you can break the insulation into small chunks. 
  • Throw a piece at the window. Throw the broken insulation piece at the window, and if you apply enough force and have luck on your side, the window will shatter. 

Summary

The components that make up a spark plug make it the perfect tool to shatter a car’s glass in an emergency situation. Spark plugs are denser and more rigid than most objects you might have in and around your car, making them an excellent pick to break your windows.

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