1 story
·
0 followers

Bouncy Balls

9 Comments and 28 Shares

Bouncy Balls

What if one were to drop 3,000 bouncy balls from a seven story parking structure onto a person walking on the sidewalk below? Should the person survive, what would be the number of bouncy balls needed to kill them? What injuries would occur and what would the associated crimes be?

—Ginger Bread

After falling from seven stories, the mass of bouncy balls would be moving at about 20 meters per second.

20 meters per second is about how fast an average person with a good arm could throw a bouncy ball. Therefore, to determine the result of an impact, we can make use of what Einstein called a gedankenexperiment, or "thought experiment":

In science, it's important that results be repeatable, so let's try that again:

The tricky thing about this scenario is that 3,000 one-inch bouncy balls is not as many as you probably think—it'd be enough to fill a large bucket.

This bucket would weigh about as much as a small child, which leads us to another gedankenexperiment:

Of course, in reality, the average person can't throw a small child as fast as they can throw a bouncy ball.[citation needed] Furthermore, they won't all fall in one clump. If you poured the balls from a container, they would bounce around and spread out as they fell, and most of them would probably miss the target.

This effect was demonstrated in an experiment by Utah State University students, who poured 20,000 bouncy balls from a helicopter as part of their Geek Week. The balls fell as a cloud, rather than a single mass.

If you wanted to be sure of killing someone, you'd need a lot more balls. 3,000,000 of them—enough to fill a large room—would be be enough to guarantee that the target would either be crushed to death by the impact or buried too deep to dig themselves out.

To your last question, if someone just happened to walk underneath when you dropped the bouncy balls, and they were killed by the impact, you'd most likely be guilty of some form of manslaughter.

However, by asking this question, you've shown your intent to cause harm to the victim, demonstrating clear malice aforethought. By writing in to this blog, you've probably upgraded your charge to murder.

All in all, you should probably stick to gedankenexperiments.

Read the whole story
euge521
3943 days ago
reply
it is for adults ...
popular
3943 days ago
reply
Share this story
Delete
8 public comments
internetionals
3922 days ago
reply
Look out solar system, here we come...
Netherlands
marten
3943 days ago
reply
Shared because of the second illustration. But disappointed at the lack of a reference to the Sony Bravia commercial from 2005.
Groningen
knicpfost
3943 days ago
that is the only commercial i have ever saved to my hard drive to watch repeatedly.
fredw
3935 days ago
link?
knicpfost
3935 days ago
http://vimeo.com/14504562 ... turn on HD!
fredw
3935 days ago
Thank you!
richard4339
3943 days ago
reply
This might be my favorite what if.
Sycamore, IL
knowtheory
3943 days ago
reply
I'm beginning to suspect that WhatIf is just an excuse to search youtube for unusual videos.
tedder
3943 days ago
reply
had me at "the average person can't throw a small child as fast as they can throw a bouncy ball.".
Uranus
JimRPh
3943 days ago
Actually, it leads to the "how many small children" question.
mkalus
3944 days ago
reply
:)
iPhone: 49.287476,-123.142136
stavrosg
3944 days ago
reply
This.
Rodos, Greece
rclatterbuck
3944 days ago
reply
.
ksteimle
3944 days ago
Point of fact: the link for "citation needed" points to http://en.wikipedia.org/wiki/Cetacean Randall Munroe is awesome.
jheald1
3944 days ago
Point of fact: the link to Wikipedia's "citation needed" page includes an xkcd comic. :http://en.wikipedia.org/wiki/Wikipedia:Citation_needed
ksteimle
3944 days ago
Ha! how awesome!
rgsunico
3944 days ago
Crazy!