Introduction: How to Crush Cans...with Science!

Picture of How to Crush Cans...with Science!

I've been a long time fan of crushing things since the days when crushing up cans for recycling meant an afternoon with a croquet mallet and a pile of cans...good times.

What could be more fun than instantly crushing a can while demonstrating the amazing power of science!

In full disclosure, this is a trick I learned from my dad, Jetpack Prime, who long ago "went pro" with his Instructables in that he is a physics professor (a really good one).

This is also my first instructable with my nephew, Jetpack6, as cameraman.

Warning! This instructable involves hot things such as heated metal and boiling water. Be very careful!

Step 1: The Set-Up

Picture of The Set-Up

For this demo, you will need a can or plastic bottle. I find that metal cans work best and soda cans are well suited. A well-cleaned oil can can also be used to dramatic effect. I will start with the bottle.

You will also need a stove, fire, or hot plate and a container of room-temperature water. A healthy curiosity and adventureous personality is always helpful.

Fill the first half of an inch to an inch of your bottle with water.

For the platic bottle I suggest indirectly heating it. To do that, immerse the bottom of the bottle in a pot of boiling water until the water in the bottle boils. Do not leave on the cap!

Do not let all of your water boil off!

Step 2: Crushing Time!

Picture of Crushing Time!

With appropriate handling tools (such as tongs) remove the bottle from the water and quickly put the cap on tight. Quickly put the bottle into the water bath to cool it.

As the bottle cools, the steam will condense back into water. Since much of the air is displaced by the steam, all that will be left is a vacuum. That leaves aroung 14.7 pounds per square inch of crushing force to collapse the bottle.

I would be a very poor Insructabler at this point if I didn't tease you with a video:

Step 3: Cans for Faster Action

Picture of Cans for Faster Action

I don't know about you, but the bottle was not as thrilling as I had hoped. Although plastic bottles work fairly well, I find that metal cans work best and soda cans are well suited. A well-cleaned oil can can also be used to dramatic effect.

Again, fill the first half of an inch to an inch of your can with water. I suppose beer will work, but it will get messy.

Heat the can directly over your heat source until the water inside is at a healthy boil. You will hopefully see steam coming from the lip.

Do not let all of your water boil off!

Step 4: Metal and Steam

Picture of Metal and Steam
This step sounds like a bad Steampunk novel, but it is much more exiting.

I'll remind you of the hot searing metal and steam you are handling. Do not let kids do this step, let them watch from a safe distance and wish they were "grown up".

To crush the can, quickly remove the can from the heat and drop it, inverted, into the water tank. The inverted part is important as the cooling water will resist the sudden inrush better than the air would. The incomming water will also further cool the can.

Why do the cans crush so well? The metal construction tends to be set up better for sudden collapse as compared to the plastic bottle. The metal will also permanently deform for more drama. Because the can can handle direct heat, you will get the can to have more heat transfer for a faster boil. Also the can is a good heat conductor for a faster boil but also for very rapid cooling during the crush phase.

I know what you are saying, “Video or you are a liar!” Well, despite your rudeness, here is the video you want:


emilyvanleemput (author)2012-07-28

didn't jou mean with science?

Jetpack5 (author)emilyvanleemput2012-07-28

Er...yes. It's either that or with Séance...which would involve more concentration and less boiling.

Jetmaster360 (author)Jetpack52015-11-10

I see what you did there...

Jetpack5 (author)Jetmaster3602015-11-10

Indeed, sir.

About This Instructable




Bio: I'm a Mechancial/Aerospace Engineer that likes to tinker in my spare time. I make my own Christmas Cards.
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