Today’s Wonder of the Day was inspired by Jonathan. Jonathan Wonders, “What is an implosion?” Thanks for WONDERing with us, Jonathan!

You might know a thing or two about how skyscrapers are built. You may have even learned about the people who work hard to make sure buildings stay standing. Today, though, we’re talking about how they come down.

The answer may seem obvious—a wrecking ball might be the fastest way to tear down a building. However, this can cause problems for the surrounding area. Using a wrecking ball on a crowded city block could cause more damage than intended. In situations like this, demolition crews often opt for implosion instead.

What is implosion? It’s when an object collapses in on itself. In the case of demolition, that means the building falls straight down. This helps avoid damage to surrounding buildings and cuts down on the spread of debris

How does implosion work? The trick is to take out the right supports to cause the building to fall in toward its center. This is done by setting off explosives in key spots inside a structure. Beforehand, members of the demolition crew learn everything they can about the building. They study blueprints and tour the space. This helps them learn where to place explosive devices.

Once the devices are in place, there’s only one thing left to do. You guessed it—detonation. After the explosives are set off, gravity takes over. Without support, the building falls to the ground.

Of course, buildings aren’t the only things that can implode. Under certain circumstances, even objects as strong as metal tanks can collapse in on themselves. How can this occur? It happens when the pressure outside of a tank is more powerful than the pressure inside.

In 2016, the show “MythBusters” looked into how this could happen. They steam-cleaned a metal tank car and sealed the hatch before the inside of the car was dry. As the steam cooled, its atoms moved closer together. This caused the total matter inside the tank to shrink, resulting in lower pressure. The air pressure outside soon overcame that inside. This caused the tank car to implode, crumpling in on itself.

The science behind implosion affects the design of many objects. One example is submarines. They need a level of air pressure that can withstand the force of the surrounding water. A change in pressure or damage to the submarine’s exterior can cause major issues. Implosion is certainly not a desired outcome for these vessels.

In other cases, though, implosions can be fun to watch. For instance, people often gather to see this process bring down tall buildings. Others enjoy trying it out on small metal containers, like aluminum cans. This can be an exciting way to learn about science.

Standards: NGSS.PS1.B, NGSS.PS2.A, CCRA.R.1, CCRA.R.2, CCRA.R.4, CCRA.R.10, CCRA.W.4, CCRA.W.7, CCRA.SL.1, CCRA.SL.2, CCRA.L.3, CCRA.L.6

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