Make Your Own Tanker Implosion With a Soda Can
It might be one of the most challenging myths, but the MythBusters did it—they made a train tanker implode. And here’s the good news—you can do something similar at home.
What Causes the Implosion?
The tanker implodes because of pressure. In this case, it is air pressure from the surrounding atmosphere. Normally, the pressure inside and outside the tank are approximately the same—about 105 Newtons per square meter. But what would happen if you removed all the air from the inside of the tank? You would have atmospheric pressure pushing in on the tank, but nothing pushing out. It would be up to the structural integrity of the tank walls to prevent it from collapsing. But think about that atmospheric pressure—105 Newtons for every square meter. That’s the same as 14.7 pounds every square inch. Serious stuff.
The tank might be made of metal, but the total force from the air pressure is just going to be too much to prevent a collapse. You would need something much thicker to hold a vacuum on the inside—something more like a submarine with thicker and stronger walls.
But how do you get all the air out of a train tanker? Of course you could just hook up a pump to get the air out, but what fun is that? The most common method of accidental vacuums inside of tanks is caused by steam (water vapor). If you fill the tank with water vapor, this pushes most of the air out of the tank. As the water vapor cools it condenses to liquid water. Now you have a little bit of liquid inside the tank instead of a large volume of water vapor. This decreases the internal pressure enough to cause a catastrophic collapse.
Would you ever fill a tank with steam? Absolutely. Just imagine cleaning the inside out with some type of steam wash—that would do it. Now seal the tank and wait for the vapor to condense and BOOM.
Crushing a Soda Can
Here is the part where you get to do something similar at home. It’s no more dangerous than boiling water to make tea. First gather your supplies. You just need an empty soda can as well as ice and some method to heat up water. An electric stove top will work just fine.
We need to fill this can with water vapor. That’s fairly easy to accomplish. Just pour a small amount of water into the bottom of the empty can and then place it on the burner. Turn the burner on until the water starts to boil. Wait until you can hear the water boiling and see the steam coming out of the can.
Here you can see I use a typical hotplate as you would find in a lab. While the water is coming to a boil, you need to get some ice water. You just need enough water and ice so that you can dunk the top of the can into it. A bowl or pot would work just fine—I used a small plastic container.
Once the water in the can is boiling, use some tongs and turn the can over into the ice water. That’s it. You should get a nice can crunch like this.
Why use ice water? The ice cools the can off so that the water vapor condenses quickly. The water covers the opening of the can and prevents air from going into it. You need this to happen fast or the water will get sucked up into the can, preventing the pressure difference that would cause your can crush.
OK, you can do this at home—but remember the can is hot. Just use common sense. If you don’t have an electric stove burner, you can put the can with water in a pot of boiling water. You should get the same effect. If it doesn’t work the first time, just try it again.