Identifying the Gold & Titanium Balls

[Sakha]

You have 2 balls. Both are identical in size and mass, but one is made of gold and is hollow,the other is not hollow and made from titanium. Find out which is which ball, and let's say both are covered with a black paint that is anti reflective, heat/electricity insulator. You can't use any measurement device, nor hitting, damaging or breaking the ball..

P.S: There's a really simple way.

 

[DaveC426913]

Knock them? One will sound hollow?

 

[Sakha]

Mmm.. let's say the paint is anti-acoustics.

 

[lisab]

Spoiler

Roll the balls side-by-side down a ramp. The solid ball will roll faster.

 

[Sakha]

wheew.. you're fast..

 

[DaveC426913]

wheew.. you're fast..

Around here, we like our women that way.

 

[regor60]

drop them in water. the hollow one will bob higher.

oh..same mass, never mind

 

[Sakha]

drop them in water. the hollow one will bob higher.

oh..same mass, never mind

Nice try.

 

[arildno]

Remove the paint?
(This as an alternative to lisab's suggestion)

 

[some_one]

oohh rigid bodies that's really good

 

[some_one]

put them in a bucket of water
they vary in density
the gold will pull out more water
am i correct?

 

[Sakha]

Remove the paint?
(This as an alternative to lisab's suggestion)

As I said, you can't damage nor break the ball, and removing the paint would be considered damaging. But yeah, lisab's answer is right.

put them in a bucket of water
they vary in density
the gold will pull out more water
am i correct?

Both would pull same amount of water because both are same size and mass, so they have same volume and density.

 

[arildno]

I think black is a damaging colour, I'm merely prettifying the balls..

 

[some_one]

aaahhh disregard it
you sayed that the gold ball is hollow

 

[Sakha]

No, imagine a gold sphere as an "o" the black line is gold and the white is hollow... The titanium sphere is all solid.

 

[some_one]

if you shoot them out of a cannon
the gold ball will not fly in a steady trajectory
because its hollow

in order to fly in a steady way you need to have a full ball

because from my knowledge
the AK bullets have a shifted center of mass
which make them highly unstable
and when they hit a person
instead of going forward
they are starting to swirl inside the victim

am i correct?

 

[arildno]

The middle of the gold ball is empty, some one, it is hollow.

The hollowed gold ball can perfectly well have the same size and mass as the compact titanium ball

 

[Sakha]

if you shoot them out of a cannon
the gold ball will not fly in a steady trajectory
because its hollow

in order to fly in a steady way you need to have a full ball

Actually I don't know. I didn't went that far.

 

[LowlyPion]

Titanium is paramagnetic.

 

[some_one]

i am not a physicist but i had some small experience with fire arms

and i know for a fact that bullets with a shifted center of mass
are swirling inside the victim instead of going threw him

the question is whether the hollow ball considered to have a shifted center of mass

 

[Sakha]

No, the center of gravity is the center of the ball (geometric). For both balls.

 

[some_one]

these materials have different electric resistance

so plug it threw an electric circuit
and mesure the resistance using ohms law
i know that the gold in a pretty good conductor so it should have less ressistanse

 

[Sakha]

You have 2 balls. Both are identical in size and mass, but one is made of gold and is hollow,the other is not hollow and made from titanium. Find out which is which ball, and let's say both are covered with a black paint that is anti reflective, heat/electricity insulator. You can't use any measurement device, nor hitting, damaging or breaking the ball..

P.S: There's a really simple way.

anti reflective, heat/electricity insulator.

 

[some_one]

there are particles called miuons which go threw any thing
and they will go faster threw the hollow ball

 

[DaveC426913]

The OP has stated that no measurement device can be used.

To which I will make 2 qualifiers for you picky types:
1] He means no man-made measurement device, i.e. eyes and such are allowed.
2] He is indicating that this can be solved without resorting to any man-made measurement. The test is easy, the results are obvious.

 

[some_one]

the only solution is this rigid body property
i can't think of any better answer

 

[DaveC426913]

if you shoot them out of a cannon
the gold ball will not fly in a steady trajectory
because its hollow

in order to fly in a steady way you need to have a full ball

because from my knowledge
the AK bullets have a shifted center of mass
which make them highly unstable
and when they hit a person
instead of going forward
they are starting to swirl inside the victim

am i correct?

The balls do not have a shifted centre of mass though. Thery are symmetrical.

Good try though. You're getting warmer.

 

[LowlyPion]

Titanium is paramagnetic.

... and gold is diamagnetic.

Enough clues yet?

 

[DaveC426913]

... and gold is diamagnetic.

How will you know without an instrument to measure it?

 

[LowlyPion]

How will you know without an instrument to measure it?

You will know by utilizing the paramagnetic quality of the titanium. You place the ball in a magnetic field and then use another magnet to detect which one exhibits an attractive force. No measurement involved.

 

[DaveC426913]

use another magnet to detect which one exhibits an attractive force.

That would be a measurement device, albeit a simple one, making a measurement, albeit a simple one.

 

[LowlyPion]

Alternatively you can use a penny or a copper stylus and try to scratch it.

The copper is harder than gold but not as hard as titanium.

 

[LowlyPion]

That would be a measurement device, albeit a simple one, making a measurement, albeit a simple one.

I would claim that it is detection, not measurement. And if detection is not allowed ... then what is?

 

[DaveC426913]

Alternatively you can use a penny or a copper stylus and try to scratch it.

The copper is harder than gold but not as hard as titanium.

PLEASE READ THE CRITERIA BEFORE CONTINUALLY OFFERING INVALID RESPONSES.
- both are covered with a black paint that is anti reflective, heat/electricity insulator.
- You can't use any measurement device,
- nor hitting, damaging or breaking the ball

 

[DaveC426913]

I would claim that it is detection, not measurement. And if detection is not allowed ... then what is?

It is detection with a device. There is a naked eye obvious way of telling the difference, (if you know what do with the ball )...